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to issue 131 of Linux User & Developer Mihalis Tsoukalos has over 15 years of

UNIX system administration and programming experience and has been using Linux since 1993. He is also proficient in Oracle database administration, Cisco IOS and Cocoa. In this issue Mihalis shows us how to sync files with Unison, a useful open source CLI tool (42-45).

Himanshu Arora is a software programmer,

open source enthusiast and Linux researcher. His articles have been featured on IBM developerWorks and Computerworld among others. He also blogs at mylinuxbook.com. This month he shows us how to make the most of Vim with his expert guide starting on page 62.

Michael Reed is a technology writer, and he’s

been hacking away at Linux for over 15 years. He specialises in desktop Linux solutions among other things. In issue 131 Michael shows us how to get started with databases using LibreOffice – it’s easier than you might think. See his work on pages 34-37.

Jon Masters is a Linux kernel hacker who has

been working on Linux for some 18 years, since he first attended university at the age of 13. Jon lives in Cambridge, Massachusetts, and works for a large enterprise Linux vendor. You can find his indispensable Kernel Column on pages 22-23 this month.

Gareth Halfacree is our new resident news

reporter and brings us the latest from all over the open source ecosystem, starting on page 14. Also this issue, Gareth speaks to Intel about its new dev platform MinnowBoard on page 6. You can also find his review of this potential RasPi-beater on pages 12-13.

Rob Zwetsloot studied aerospace engineering

at university, using Python to model complex simulations in class. Along with tutorials, reviews and more this issue, Rob tells us which IDE we should be using (pages 72-77) and walks us through the build process of an Onion Pi (pages 46-49).

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Welcome to the latest edition of Linux User & Developer, the UK and America’s favourite open source and Linux magazine. When you’re trying to make the best Linux and open source read in the world, there’s nothing more useful than feedback from readers. There’s little point us being here if we don’t aim to give you a healthy dose of what you want, so we pay close attention to what you have to say. But what have you been saying? After collecting, formatting, graphing and a lot of stubble scratching, it’s clear many of you want more tutorials, bigger reviews and more introductory and intermediate developer content. As you’ll see this issue, we’ve dedicated more pages to tutorials and guides than ever before and we’ve even reformatted our distro reviews to make them more useful. We still need your help, though. If you’re keen to learn more about development in the open source field, we want to know what languages and frameworks you care about. We’ve been focusing very heavily on Python in recent months and intend to continue with this, but would you like to see Qt, Vala and C++ here too, or something else entirely? Let us know on Facebook and Twitter or simply drop me an email directly at [email protected]. Russell Barnes, Editor

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Exclusive

Intel’s big fish in a little pond

n Scott Garman is a Yocto Project engineer at Intel, and the company’s evangelist for the MinnowBoard


We chat to Scott Garman about Intel’s first foray into the world of Linux-powered open hardware development systems Scott Garman, the man Intel has appointed as the ‘evangelist’ for its first steps into open hardware development, has a history of embedded development. “I’m not a hardcore kernel hacker,” he tells us during an interview to commemorate the launch of the MinnowBoard single-board computer, “but a generalist who enjoys working with the big picture in mind.” A software engineer for the Yocto Project, a collaborative effort to make the development of Linux distributions for embedded platforms as simple as possible, working under Intel’s

6 www.linuxuser.co.uk

Open Source Technology Center, Garman has already given plenty back to the community. He’s responsible for Yocto-related training materials, including one of the most popular screencast introductions to the project, and is now leading the effort to introduce the first open hardware platform designed with Yocto firmly in mind: the Intel MinnowBoard. The MinnowBoard, reviewed on page 12, owes a clear debt of gratitude to devices like the Raspberry Pi and the BeagleBoard. Designed around Intel’s ‘Queens Bay’ platform, which has

at its heart a low-power 32-bit Atom processor, the board is designed as a development platform to bring the flexibility and familiarity of the x86 instruction set architecture to embedded systems – and to do so at a low cost. Most surprisingly of all, the device is open hardware: all specifications, schematics, board layouts and firmware packages are available for download and reuse under a permissive licence – a first for an Intel hardware product. Clearly, this is a departure from the norm, and one of which Garman is understandably proud.


How the MinnowBoard came about

InTervIew

The open hardware movement

n The MinnowBoard itself

is compact yet powerful, and boasts impressive I/O capabilities

“To my knowledge, MinnowBoard is the first hardware platform designed with the Yocto Project in mind” n Along with the power and reset buttons on the right, the MinnowBoard boasts four programmable buttons

How did the MinnowBoard come about? “I’d say development in earnest started happening at the end of 2012. MinnowBoard was an unusual project because of the way Intel and CircuitCo [the company behind the BeagleBoard and BeagleBone development platforms] collaborated on it. The Intel Yocto Project team provided input to help design the requirements for MinnowBoard around performance, openness, flexibility and standards. CircuitCo then used an Intel reference design – the ‘Queens Bay’ platform – and adapted it as needed. They also manufacture and sell the MinnowBoard, so it’s primarily their product, not Intel’s. The result is a win-win situation where our team got a great development platform and more, and CircuitCo has a compelling product platform to sell. “We’ve been really happy to work with CircuitCo on this, because they understand the open hardware/open community model so well, but we both had plenty of things to learn from each other during the process of bringing

n Open hardware – an offshoot of open source, where the schematics, component lists, and even the individual Gerber files for having printed circuit boards made are released under a permissive licence – is growing increasingly popular. Although the Raspberry Pi, one of the most popular low-cost embedded development platforms, is proprietary, many of its competitors are more open: as well as the MinnowBoard, the Gizmo, the BeagleBoard and its smaller BeagleBone offshoot, the Olimex OLinuXino family, and the microcontroller-based Arduino range are all open hardware. Open hardware can lead to rapid advances in features and technologies for the projects that adopt it, but as with open source software there are risks: the Arduino’s open nature has led to it being one of the most copied projects around, with Far Eastern factories churning out illegitimate clones by the dozen and misappropriating the project’s trademark in direct contravention of its otherwise extremely permissive licence.

up this first board. It’s turned out to be a great collaboration and we’re really pleased with the results. “In one sense, the Intel team working on this is extremely small. At the same time, I wouldn’t want to discount the contributions that many people have done to help make this happen, even if they weren’t involved with the project fulltime on a daily basis.” What led to the decision to choose the Queens Bay platform, with its ‘Tunnel Creek’ Atom processor, in the MinnowBoard? “Two main issues led us to use Tunnel Creek CPU for MinnowBoard. One, we were looking for longevity of the platform. Going with an open hardware model means that this is going to be an attractive board for embedded product companies to use and adapt for commercial products. I can tell you from experience, there is nothing more frustrating

n The MinnowBoard sits on four stilts to help aid the passive cooling of its 1GHz Intel Atom processor


Exclusive


■ Larger and pricier than the Pi, the MinnowBoard offers full x86 compatibility

than developing a successful embedded product and then finding out that your components are about to enter end-of-life. Queens Bay is a platform used in IVI [In-VehicleInfotainment] devices, and was designed with a long lifespan – since people tend to own cars for a long time. It still has four to five years left in the product’s life cycle. “Two, the time to execute was now, so we weren’t about to wait for upcoming Intel platforms to roll out. Tunnel Creek met our main requirements and was available immediately, so we ran with it.” What advantages does the x86 architecture used in the Atom processor offer in the embedded space, compared to ARM or other RISC platforms? “Compatibility is likely the biggest advantage. Linux originated on the Intel 386, and whether you’re working on embedded or desktop applications, the toolchain, libraries etc were designed on and are pretty much guaranteed to work on x86. “Performance is another significant one. Countless person-years have been put into optimising compilers such as GCC to take full advantage of x86 platforms, so you can leverage that to its greatest benefit.” ■ The MinnowBoard includes eight GPIO pins and a dedicated expansion port for ‘Lures’


Do you agree that the success of the ARMbased Raspberry Pi has demonstrated a clear demand for low-cost development boards from hobbyists? “Yes, absolutely. One of the things I appreciate and respect about the Raspberry Pi project is that it’s introducing so many new people to embedded Linux development. It used to be that embedded was a niche thing that software engineers specialised in, and now the embedded Linux community is becoming much more diverse, especially with younger people. I love that.” What does the MinnowBoard offer that other, more established development boards lack? “MinnowBoard stands out in its combination of performance, flexibility, openness and

standards. The Intel Atom CPU provides plenty of performance for high computational workloads. It also has strong I/O performance due to PCI Express powering its Gigabit Ethernet and SATA disk features. We also make PCI Express available through MinnowBoard’s expansion connector to enable high-speed I/O to custom hardware projects, for example interfacing with FPGAs or other hardware. “The MinnowBoard can be used for fun hobby projects, yet scales up to higher workloads. It’s expandable via several PC and embedded bus standards, and offers an environment for custom firmware development.

■ With Gigabit Ethernet and a real-time clock, it pulls ahead of the Raspberry Pi


How the MinnowBoard came about

INTERVIEW

“The open hardware model is very attractive in empowering your customers” MinnowBoard includes PC architecture standards including PCIe, USB and SATA, as well as embedded standards such as SPI, I2C, GPIO and even [a CAN bus] for automotive applications. It was designed with the Yocto Project in mind, which is an industry-wide standard for embedded Linux.” The MinnowBoard is open hardware – how important do you think that will be to its success in the market? “The open hardware model is very attractive in empowering your customers and allowing them to innovate in ways you can’t anticipate. Since people are free to reproduce and customise the MinnowBoard, the sky is the limit with this board’s potential. I think this will be fundamental to [its] success. “Keep in mind that open hardware is meaningful not only if the design files are available, but when all the parts are available through accessible distribution channels and the board’s price is not subsidised. If someone wants to rebuild it, or rebuild something similar, they can at about the cost it’s being sold for now. Not many boards can offer that potential.” What made Intel get involved in hobbyist-level embedded computing development? “We wanted MinnowBoard to become a useful platform for Yocto Project development that encouraged experimentation and the pursuit of fun projects in addition to more serious embedded applications, as a board we would use in Yocto Project training courses. And we needed it to be flexible enough so you could do interesting things in a classroom-style setting, which lines up with what hobbyists want, too.” With the board now in the hands of early adopters, have you seen any particularly innovative or exciting applications for the MinnowBoard emerge from the community?

“It’s still a bit early for me to have good visibility into this, as the board has only been available for about three weeks [at the time of the interview]. As I hear about community projects, I do intend to highlight them on our social media channels. “I am aware of someone who plans to use a MinnowBoard as part of a quality control system for 3D printers by making use of computer vision capabilities. I’ve also heard that folks in the FGPA design community are quite interested in the MinnowBoard due to its high-speed expansion capabilities. There’s also a group of students interested in building out learning exercises on the MinnowBoard, as a way to advance their embedded design skills.” Intel has something of a mixed history with the open source community - in particular in failing to release graphics drivers for selected Atom processor models. With the MinnowBoard being truly open, does this signal a shift in attitude towards the open source and open hardware communities at Intel? “The Open Source Technology Center at Intel is full of incredibly talented, well-known and passionate people who care deeply about openness. In recent years this group has grown dramatically in both size and influence, and it reflects the reality of the increased influence open source plays in the global software ecosystem. “Intel’s Core graphics have open source drivers that work with hardware acceleration, and the upcoming Bay Trail Atom platform makes use of it. This will address the issue you mentioned with graphics drivers on Atom. I’m looking forward to this, and I think Intel is definitely moving in the right direction in this regard.” Intel and CircuitCo have published a list of current and proposed add-on boards, dubbed Lures, for the MinnowBoard. Is there a particular add-on you would like to highlight? “One of the Lures that I’m sure will be quite popular is the Trainer Lure – the one based on an Arduino [microcontroller]. Combining the computational power of MinnowBoard with

Queens Bay

The code name for the combination of an Intel Atom E6xx-series processor with the EG20T controller hub (code-named Tunnel Creek and Topcliff respectively), Intel launched the Queens Bay platform in 2010 with the embedded market firmly in mind. Initially, the company targeted in-car computer systems for navigation and entertainment – so-called ‘infotainment’ devices – but claimed the platform would be equally at home in gaming, communications, point-of-sale, industrial and digital signage applications. The Tunnel Creek family of processors are not true system-on-chip designs, offloading much of the circuitry to the EG20T chip, but do include the CPU, a graphics processor supporting up to two simultaneous displays, an audio controller and a hardware video codec on a die some 46 per cent smaller than its predecessors. Until the launch of the MinnowBoard, however, using Queens Bay in hobbyist applications was almost impossible: Intel’s official development board was provided only to registered hardware partners, and came with the expectation that you would be placing an order for a few thousand processors once you had finished your design.

the embedded input/output capabilities and community of Arduino will open up a lot of interesting possibilities.” How critical is Linux and the Yocto Project to the MinnowBoard’s success? “We designed the board to be a Yocto Project development platform, and Yocto produces embedded Linux distros. So it’s pretty core to our purpose. It was the primary motivation behind the project itself – to my knowledge, MinnowBoard is the first hardware platform designed with the Yocto Project in mind. But most people using the MinnowBoard may have no knowledge of or interest in the Yocto Project – that’s okay, too.” Is the MinnowBoard likely to be the first in a family of open development boards from Intel, or is it merely an experiment for the company? “There are a lot of people within Intel who are excited about open hardware. I can’t speak [about] any specific future product plans, but I think the future is very, very bright.”


Specifications

MinnowBoard vs Raspberry Pi

MinnowBoard Intel’s Atom-powered development board is the first to be Yocto Projectcompatible and runs Angström Linux. While considerably more expensive than the Raspberry Pi, it utilises the x86 architecture so offers computational power more akin to desktop and mobile computers. It’s also a very complete package, offering both Angström Linux on a microSD card and a properly rated power supply in the box. However, without decent driver support for the Intel GMA 600 GPU and a DVI-over-HDMI video interface (no HD audio or HDCP encryption), it lacks the same multimedia appeal as the Raspberry Pi.

■ SATA support brings mass storage within easy reach of MinnowBoard

■ The MinnowBoard supports tinkerers with two on-board LEDs and six buttons

■ Analogue audio input is a definite step up from the Raspberry Pi

■ Four stilts and bigger dimensions mean it towers over the RasPi

■ The stilts increase airflow to help keep the 1GHz Intel processor (under heat sink) cool

MinnowBoard Specs Price Dimensions Weight Operating system Processor Video Max resolution Memory

Output Input

Networking Real-time clock Extras

■ It has fewer GPIO pins, ■ Gigabit Ethernet means but includes two LEDs and faster networking – great four buttons to control if you’re planning a server


■ MinnowBoard needs a staggering 2.5A to keep its lights flashing

Power

£162 106 x 115mm 119g Angström Linux (Yocto certified) supplied on microSD 32-bit Intel Atom E640T single-core at 1GHz Embedded Intel GMA 600 1366 x 768 (no HDCP encryption) 1GB DDR2 (shared), 4MB SPI flash (firmware storage) DVI-over-HDMI (no audio), analogue audio out Analog audio in, 2x USB, 1x SATA-2, 1x micro-USB, 1x mini-USB, 1x serial console, SD card slot, 1x micro-SDIO, 8xGPIO pins 10/100/1000 Ethernet Yes (no battery installed) Lure connector with CAN bus, HD audio, LVDS, IC, 3x PCI Express, SATA-2, SDIO, SPI bus, UART, 2x USB 5V at 2.5A (adaptor included)

VS

MinnowBoard vs Raspberry Pi

COMPARED

Raspberry Pi The Raspberry Pi has inspired thousands to try Linux for the first time and reinvigorated interest in bare-metal computing. It opens the door to the creation of fascinating Internet Of Things projects and drastically lowers the barrier of entry for both programming and physical computing. It’s not all plain sailing, though. Its low-price means the out of the box experience isn’t stellar. One still needs to acquire a microSD card, an HDMI cable and power supply, meaning ‘starter packs’ can retail upwards of £60. While its raw processing power is left in the shade by Intel’s x86 CPU, the Raspberry Pi continues to amaze users with its remarkable multimedia prowess.

■ Standard SD card support is good, but highspeed SD cards are worth the extra expense

Raspberry Pi Specs Price Dimensions Weight Operating system Processor Video Max resolution Memory Output Input Networking Real-time clock Extras

Power

£28 86 x 54mm 40g None included (Raspbian & others supported) ARM1176JZF-S (armv6k) single-core at 700 MHz VideoCore IV Full HD with HDCP encryption 512MB DDR2 (shared) DMI (with HDCP encryption), composite RCA, analogue audio out 2x USB, 1x micro-USB, SD card slot, 26x GPIO pins 10/100 Ethernet No (can be added via GPIO) DSI display connector, JTAG headers, CSI (camera module) connector, SPI bus, I2C, UART 5V at 700mA (not included)

■ A microSD card slot would have been preferable here

(Model B, Rev. 2)

■ The Pi’s small size makes it ideal for hiding behind a monitor or stashing in a project box

■ The RasPi could really do with a Lure port - even just two more USB ports would be great

■ The multimedia support is frankly stellar

■ 26 GPIO pins means there’s massive scope for tinkering. No analogue support, though, sadly

■ The Broadcom SoC is brilliant, even if it chugs occasionally

■ The audio on the RasPi is probably its weakest aspect. No mic support either


Review

Intel MinnowBoard

■ The Lure connector, for addon boards, carries everything from CAN bus signals to three PCI Express lanes

■ An HDMI port offers DVI video connectivity, but does not carry digital audio

■ Two USB ports provide connectivity for external peripherals ■ Gigabit Ethernet gives the MinnowBoard powerful networking capabilities

DEV PLATFORM

Intel MinnowBoard

£162.83 ($200)

Intel’s answer to the Raspberry Pi is here – but at nearly six times the price, can it tempt buyers back to x86?

Pros

Powerful, flexible, open; a familiar x86 environment for newcomers to embedded development

Cons

Compared to ARM equivalents it’s expensive, and its performance lags behind AMD’s rival Gizmo device

Clearly, the MinnowBoard is no Raspberry Pi. Measuring 102mm on its shortest side, it’s significantly larger, requires a whopping 2.5A from a 5V power supply to run and costs almost six times as much as the credit-card-sized Pi. The MinnowBoard does offer something the Pi lacks, however: full x86 compatibility. At the heart of the MinnowBoard is one of Intel’s less powerful processors: the Atom E640T. Running at 1GHz, the single-core chip offers a 32-bit x86 implementation – already putting it on the back foot compared to the dual-core 64-bit APU found on rival AMD’s Gizmo, the closest device for comparison – while generating a surprisingly small


amount of heat, allowing for passive cooling through a compact heat sink. With 1GB of RAM, the MinnowBoard offers a surprisingly powerful yet lightweight platform for embedded computing. Peaking, during testing, at 7W from the socket, it scored a respectable 95th percentile time of 11.49ms – almost five times faster than the Raspberry Pi at 51.45ms, but still some way behind the Gizmo’s impressive 9.87ms score. Add in the fact that the Gizmo can run two threads simultaneously and it’s clear Intel isn’t going to win on outright performance – although it has included Hyper-Threading support in the MinnowBoard for pseudo dual-core operation.

Intel MinnowBoard

x86-based embedded development board

REVIEW

■ A micro-SDIO slot plays host to a bundled SD card containing the Angström operating system ■ A small heat sink passively cools the Intel Atom E650T processor

■ Bundled risers lift the board up in order to allow the processor room to cool

Technical specs

Operating system Processor Video Memory Dimensions Weight Input/Output

Angström Linux (Yocto Certified) 32-bit Intel Atom E640T single-core at 1GHz Embedded Intel GMA 600 1GB DDR2, 4MB SPI Flash (Firmware Storage) 106 x 115mm 119g (excluding PSU) DVI-over-HDMI, Analogue audio in & out, 2x USB, 1x SATA-2, 1x USB device, 1x Serial console, Gigabit Ethernet, 1x micro-SDIO Extras Lure connector with CAN bus, HD audio, LVDS, I²C, 3x PCI Express, SATA-2, SDIO, SPI bus, 2x UART, 2x USB Power 5V at 2.5A

Treating the MinnowBoard as a standard computer, however, misses the point entirely. The device is designed for embedded development, and to help Intel regain a foothold in a market that has become almost completely dominated by ARM-based systems. Accordingly, it includes eight buffered general-purpose input-output pins, along with two user-controllable LEDs and a set of four switches. Together, these turn the MinnowBoard into a ready-to-run system for developing embedded applications – and unlike with ARM-based devices, those used to an x86 toolchain don’t have to learn anything new. The board also includes an expansion connector for addin daughterboards dubbed ‘Lures.’ Designed to be analogous to the ‘shields’ of the Arduino microcontroller, the port gives each Lure access to considerable potential: as well as three PCI Express lanes, an SDIO channel, two USB channels and more, the port carries everything from CAN to I²C buses. Although there are no Lures available on the open market at the time of writing, several are in development – including one which will offer compatibility with Arduino shields. That doesn’t mean the main board is bereft of connectivity: a micro-SDIO slot for the boot device, two USB ports, analogue audio connections, Gigabit Ethernet, and mini- and micro-USB ports for acting as a USB device or as a debug serial console are included. The board also features a SATA-2 port, offering up to 3Gbps of throughput to a mass storage device – with a second port available through the Lure expansion port if required.

Also consider

■ Four switches combine with two usercontrollable LEDs to get users started with the board’s capabilities

At present, the MinnowBoard ships with a bare-bones installation of Angstrom Linux – no friendly out-of-box experience here. With full Yocto Project certification, however, rolling your own OS isn’t a challenge and Intel is in talks with distributions including Ubuntu to add support for the board’s somewhat unique 32-bit UEFI firmware. Using documentation – still in progress – from the project’s founders, the MinnowBoard is quick to offer up its GPIO capabilities. The only real disappointment comes from the HDMI socket, which only carries a DVI signal and not the audio required of a full HDMI implementation. There’s also no support for HDCP encryption, although anyone considering using the MinnowBoard as a media playback system has probably missed the point of its design and features. Gareth Halfacree

Sage Gizmo

$199 (£154.29)

Based on an embedded AMD APU, it’s far more powerful than the MinnowBoard. Embedded graphics aid computer performance and a bundled expansion board makes getting started easy. It does, however, require more power under load. gizmosphere.org

Raspberry Pi

Summary

£28.07

The MinnowBoard is a welcome foray from Intel into the world of open hardware and offers considerable potential. While its performance may lag behind the rival Gizmo board, the Lure connector holds promise for some impressive add-ons to come – but its high price means the Raspberry Pi has little to fear from this upstart.

The Pi’s ARMv6 processor is considerably less capable than the MinnowBoard’s Atom – but at almost a sixth the price, it’s easy to overlook this in favour of having spare cash for add-on hardware and tinkering components. raspberrypi.org

More information minnowboard.org


OpenSource

Your source of Linux news and views www.linuxuser.co.uk For the latest news and views

Email us directly… [email protected]

OpEn SciEncE

Linux Foundation leads open science initiative Partnership with OpenBEL will make sharing scientific data easier A collaboration between the Linux Foundation and Selventa’s freshly opened OpenBEL project could help push the ideals of open source development further into the realms of scientific research, the groups have announced. Previously a closed-source proprietary platform, OpenBEL – the Open Biological Expression Language – was designed to help users to capture, store, share and use life sciences content through what its creators describe as a “knowledge engineering platform.” Addressing the difficulties with sharing and using data, the team behind OpenBEL has been using it for ten years – but the platform was only opened up in June last year, a move that the Linux Foundation is claiming will be the making of the project. “All of us are smarter collectively than any one of us is by ourselves, and Linux is one of the greatest examples of that principle,” claimed Jim Zemlin, executive director at The Linux Foundation. “We are able to take what we know about Linux and collaborative development and transfer that to new industries. OpenBEL represents an amazing opportunity for openness and collaboration to

nOpenBEL’s Ted Slater extols the virtues of Linux and collaborative development

advance science, and we’re happy to impart our knowledge of collaborative software development to leaders in the life sciences industry. Successful open source projects don’t just host code; they make use of a full suite of open source best practices to quickly gain adoption and collaboration. We aim to help OpenBEL achieve even more success.” “The Linux Foundation hosts the largest collaborative project in the history of computing: Linux,” stated Ted Slater, project

nOpenBEL provides a platform for the capture and collaborative analysis of life sciences data


lead for OpenBEL. “It is the standard by which all open development projects measure themselves. We know our industry can learn a lot from this neutral steward of open development and governance… Also, by hosting OpenBEL at The Linux Foundation, we have access to a variety of important services to help facilitate collaborative development, allowing our teams to focus on our subject matter: life science.” Hosting the OpenBEL platform with the Linux Foundation, its creators hope, will boost its adoption. Since going open source in June 2012, the project has already been adopted by organisations as diverse as the Harvard Medical School, the University of California at San Diego, the Fraunhofer Institute, and pharmaceutical giants Novartis and Pfizer. The groups hope that wider adoption of OpenBEL will lead to a pooling of information on life sciences, with the platform allowing for easy dissemination and analysis using a standardised set of computable networks and application programming interfaces (APIs). The deal with OpenBEL is the latest of the Linux Foundation’s Collaborative Projects, which include partnerships with the Yocto Project, Xen Project, FOSS Bazaar, and mobile platforms MeeGo and Tizen. Details on the project, and links to the source code, are available on the official OpenBEL website at openbel.org.

“All of us are smarter collectively than any one of us is by ourselves” Ted Slater

News

ThelatestintheLinuxcommunity

OPEn SOURCE

nThe DevShare programme introduced by SourceForge owner Dice Holdings has drawn strong criticism

efforts; its critics claim it’s nothing more thanmalware. “SourceForge, once a mighty force for the good of open source, has fallen far from its previous lofty heights,” opined Red Hat developer Justin Cliff in a post to the Gluster Project blog. “I’m not against monetisation at all, we all have lives and need to pay our bills. Butnotthroughabusingusertrust.Notthrough preyingontheunskilledorunwary.Tomisquote MargeSimpson:‘Theynotonlycrossedtheline, theythrewuponit.’” SourceForge, now owned by Dice Holdings, has defended the initiative. “SourceForge will always respect the rights of our users and we will never infringe on them. DevShare offers a transparentinstallationflowthatgivesusersall the necessary information to make educated choicesaboutwhatsoftwaretoinstall.” The decision to launch the programme, currentlyinbeta,hasledtocallsforhigh-profile projects to move to alternative hosts; others – including FTP client FileZilla – have, however, alreadysigneduptoDevShare.

OPEn SOURCE

X.Org loses non-profit status The Foundation behind X.Org has lost its status as a 501(c)(3) non-profit group in the US, following a failure to file taxes with the US Internal Revenue Service for three consecutive years. “I was taken by surprise that the IRS hit ussorudely,”FoundationaccountantStuart Kreitmansaidatthecompany’smostrecent board of directors’ meeting. “I’ve had little issueswithmyownreturnsandhavealways foundthemtobereasonableandfriendly.” Kreitman has, however, admitted that the tax returns have not been filed, but argued that the organisation has “never filedreturns.”

nThe X.Org Foundation is considering letting others take care of its paperwork in future

TheFoundationisnowconsideringjoining an umbrella organisation in order to reduce thepaperworkrequired of its members and prevent this sort of embarrassing situation fromrecurring.

3 - 5 October 2013

Open source hosting outfit SourceForge has been criticised for bundling selected binary releases in advertising-laden packages. LaunchedinJulythisyear,DevSharebundles software with add-ons such as AnchorFree’s HotSpotShield. SourceForge claims it provides an easy way for developers to monetise their

Le Beffroi, Paris » » France » openworldforum.org The first European summit designed to bring together technical experts and political representatives, Open World Forum includes speakers ranging from Microsoft’s Frederic Aatz to the CIO of the French Culture and Communication Ministry.

19 - 20 October 2013

“They not only crossed the line, they threw up on it”

Open World Forum ’13

OggCamp

21 - 23 October 2013

SourceForge DevShare branded ‘malware’

Linux calendar

LinuxCon Europe

21 - 23 October 2013

OPEn SOURCE

CloudOpen Europe

» LJMU Art & Design Academy, Liverpool » England » oggcamp.org The largest open source and free culture event in the UK enters its fifth year. Based around the ‘unconference’ format, there will be three fluid tracks along with a series of scheduled speakers throughout the weekend.

» Edinburgh International Conference Centre » Scotland » events.linuxfoundation.org The largest event covering Linux in general – rather than specific distributions – comes to Scotland, with over a hundred planned sessions. Followed by the Linux Kernel Summit, Automotive Linux Summit and Embedded Linux ConferenceEurope,allinEdinburgh.

» Edinburgh International Conference Centre » Scotland » events.linuxfoundation.org The second annual CloudOpen conference looks to build on the success of the first, helping push forward the use of open source technologiesincloudcomputing.


OpenSource

Your source of Linux news and views www.linuxuser.co.uk For the latest news and views


GOVERNMENT

Valencia completes LibreOffice switch Local government coffers already €1.3 million richer

The Valencian regional government in Spain has completed its planned switch from proprietary software to LibreOffice. The project to migrate to an open source alternative began in 2012, and has already been credited with saving the government €1.3 million in software licensing fees. “Apart from economic benefits, the commitment to free and open source software brings other advantages, including having the solutions available in the Valencian language as well as in Spanish, and IT vendor independence, which encourages competition,” said Sofia Bellés, director general of the Valencian government ICT department. “We also have the freedom to modify and adapt the software to our every need.”

■ Moving to LibreOffice has saved the Valencian government a small fortune

Valencia has long been at the forefront of open source adoption, having pushed a programme of Linux adoption in schools back in 2005. Covering 110,000 PCs installed across all regional schools, the move to Lliurex Linux is claimed to have saved over €30 million so far. “Installation of the free office suite is part of the regional government’s strategic commitment to its use of free software. It will not only help save costs for licences,” Bellés

added, “but also boosts the development of the local ICT sector, promotes the use of Valencian in the digital world and improves interoperability and security of the administration’s IT systems.” The move has been lauded by the European Commission’s JoinUp programme, which looks to improve interoperability between public administrations through standardisation, suggesting other governments may follow suit.

HARDWARE

ARM begins Internet of Things push Aims for a trillion devices sold by 2025 Cambridge-based low-power processing giant ARM is throwing its weight behind the Internet of Things, forming a new IoT business unit with the aim of selling a trillion devices by 2025, and purchasing IoT specialist Sensinode Oy. Claimed by its proponents to be the next logical evolution of the internet, the Internet of Things looks to equip everything possible with internetconnected sensors and interactivity as the means to making people’s lives easier. ARM plans to integrate Sensinode’s 6LoWPAN and CoAP standards with its own Cortex-based mbed microcomputing platform, which it sells both for embedded hardware development and in breadboard-friendly format for hobbyist use. “Sensinode is a pioneer in software for lowcost low-power internet connected devices and


has been a key contributor to open standards for IoT,” claimed ARM’s John Cornish of the deal. “By making Sensinode expertise and technology accessible to the ARM partnership and through the ARM mbed project, we will enable rapid deployment of thousands of new and innovative IoT applications.” The move comes as industry analysts predict a pending explosion in the number of connected devices, with Bill Morelli of IHS offering an estimate of 30 billion connected devices by 2020 – a figure that ARM is going to do its best to exceed. Small-scale IoT projects, including printers that act as Twitter gateways and environmental monitoring systems, often make use of ARMbased microcomputing systems – most

■ ARM is pushing its technologies, including the mbed prototyping platform, as the future of IoT

frequently, these days, the low-cost and highperformance Raspberry Pi or its more flexible alternative the BeagleBone Black – while others use lower-cost microcontroller devices from Atmel, Texas Instruments and others.

News

The latest in the Linux community

open source

linux

Torvalds celebrates linux 3.11 Following his decision to name Linux 3.11 ‘Linux for Workgroups,’ Linus Torvalds has posted a nostalgic message celebrating its final release candidate. “Hello everybody out there using Linux – I’m doing a (free) operating system (just a hobby, even if it’s big and professional) for 486+ AT clones and just about anything else out there under the sun,” Torvalds wrote. “This has been brewing since April 1991, and is still not ready.” The message is an amusing echo of his 1991 initial Linux release notice, which called for Minix users to try Linux and claimed it “won’t be big and professional like GNU.”

viDeoGames

metro: last light heads to linux

Linux gaming no longer being ignored by triple-A developers. Developer 4a Games has confirmed that firstperson shooter metro: last light is heading to linux following its debut on windows earlier this year. Due to arrive on Steam for Linux later this year, Metro: Last Light is one of the first big-name titles to be released on Linux in the same year as its Windows counterpart – and marks a growing trend for development houses to consider Linux as a valid target market for their software. Development of the Linux release was performed in-house at 4A Games, with the company crediting its custom game engine for making it easy to port to alternative platforms. The game will also be launching on OS X around the same time.

n4A Games has ported Metro: Last Light to Linux, for launch later this year

“We are very happy with the results,” said 4A’s CTO Oles Shishkovstov. “We hope that Mac and Linux gamers will appreciate our efforts to create the best possible version for their machines.”

malware

Hand of Thief Trojan targets linux

Experts warn users to beware as malware spreads a Trojan horse, dubbed the Hand of Thief, has been discovered targeting linux users and attempting to grab banking credentials and other sensitive data. The Trojan, discovered by RSA researchers, includes sophisticated anti-monitoring and anti-virtualisation techniques which make it hard to analyse. Sold for around $2,000 on underground sites, the Trojan is claimed to be effective against all common Linux desktop distributions. Anti-virus experts are positioning the Trojan as proof that such protective software is a requirement on Linux. “It’s yet another reason why Linux users shouldn’t be complacent about their computer security, and run an anti-virus program,” claimed former Sophos consultant Graham Cluley. “The statement that the Linux platform is absolutely secure now seems even more illusive,” added Avast!’s Peter Kálnai. However, the Trojan can only install when provided with root access – something the majority of modern desktop distributions shut off behind a password. By being careful about what is installed and not providing a password to an unexpected pop-up dialog, Linux users should largely be protected from its ravages. Those who frequently install software from outside their distribution’s official repositories, however, should take heed: as the popularity of Linux grows, sadly so too does its attractiveness to criminals.

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Opinion

The free software column

open source

open source robotics

Linux is the platform for robotics

Linux is increasingly being used for cutting-edge robotics – opening up the field to anyone interested in learning more

Alan broun is currently studying

for a PhD at the Bristol Robotics Laboratory. He is also the managing director of Dawn Robotics Ltd – www.dawnrobotics.co.uk

robotics is a fascinating subject. It links computers to the physical world, allowing them to move around, sense their environment, and to interact with it. Building your own robot, however, has traditionally required that you spend a huge amount of time and energy to get even the most basic of robotic systems up and running. You need mechanical engineering skills to build the chassis or body, electronic engineering skills to wire up the motors and the sensors, and programming skills to animate the robot, to control its body to get it to do what you want. These barriers to entry mean that people entering into the field of robotics – either in search of a stimulating pastime, or perhaps as part of more formal research – can quickly be overwhelmed by the sheer amount of work required. The initial dreams of building a robot to fetch your beer or to walk your dog get pushed further and further back, as more and more time is sucked up just getting the basics working. Things are changing, however, and the barriers to entry are falling. The relentless march of progress in consumer goods means that a lot


of commonly used robotics hardware – such as cameras, accelerometers and communication devices – are now both much cheaper and much smaller than they were ten years ago. Actually making use of electronic sensors, and motors, is also a lot easier now, as platforms like the Arduino make connecting electronic components to your computer, and controlling them, both quick and simple. On top of all this, small, powerful computers such as the Raspberry Pi and the BeagleBoard, to name but two, mean that you can now cram much more processing power into your robots at an affordable price. In order to put this hardware to good use, however, you need software, and as luck would have it, Linux is the platform where the most exciting developments in robotic software are taking place. Writing the software for modern robots can be one of the most involved and complicated parts of the process. Software is needed for controlling motors, reading values from sensors and, possibly most importantly, to provide high-level control and AI. A number of distributed software environments have been produced to try to ease the development of robotic software. But the Robot Operating System (ROS) produced by a company called Willow Garage in Silicon Valley is arguably one of the most successful. ROS is not actually an operating system, but rather a BSD-licensed open source software framework which runs on Linux. It allows interfaces to be defined for common bits of robotic software, such as the drivers for cameras and motors, and it allows this software to be run as a large number of separate processes called ‘nodes’ – either all on one machine, or transparently distributed over a network of machines.

Over the last five years, ROS has dramatically eased the process of writing robotic software. Now you can download a large number of precompiled packages to quickly allow you to hook up common sensors such as cameras or Microsoft’s Kinect. High-level services such as inverse kinematics, map building and speech recognition are easy to plug in, and ROS also provides a great selection of visualisation tools so that you can see what’s going on from your robot’s point of view. When you need to write your own software, you can do it in the language you choose. Low-level motor drivers can be written in C and then communicate over ROS’s network layer with high-level control processes, written in a language such as Python or Java. Not having access to robotic hardware is no bar to entry, as ROS also provides support for simulators such as Gazebo. ROS has been embraced by the robotics research community and so lots of simulations of cuttingedge robots are now provided by the teams who built them. So, for absolutely no cost at all, you can get access to Willow Garage’s PR2 robot, NASA’s Robonaut and Boston Dynamics’ Atlas robot. This last robot is currently being used in the DARPA Robotics Challenge, which seeks to get a humanoid robot to drive a car and move around a disaster area, so it’s ambitious stuff. Now is an exciting time in robotics, and Linux is the platform on which some of the coolest stuff is happening. If you haven’t tried it yet, then I would urge you to download and have a play with ROS, start building yourself a robot and join in all the fun!

“Not having access to robotic hardware is no bar to entry”

Can you volunteer for Code Club? Code Club is a nationwide network of volunteer-led after school coding clubs for children aged 9-11. We need people who know how to program computers to volunteer to run a club at their local primary school, library or community centre for an hour a week. We create the projects for our volunteers to teach, the projects we make teach children how to program by showing them how to make computer games, animations and websites. Get involved, let’s teach the next generation to code!

Visit www.codeclub.org.uk to find out more

OpenSource

Your source of Linux news and views

the Open SOurce cOLumn

Fair game

Simon fears the future of gaming is the future of technology

Simon Brew is a technology writer and editor, working across the Linux, Windows and Mac OS X platforms

I play games. I’ve always liked playing games, and suspect I’ll continually sneak one or two in for the rest of my days. If you talk to my editor, he’ll obviously tell you that I’m the most reliable hitter of a deadline that he’s ever met and that my words arrive perfectly formed, requiring the barest of edits before they’re laid before your

eyes. Scratch that: thanks to computer games, I’ve slipped under the proverbial door seconds before it slams shut more times than I’d care to admit. But games are changing. For someone who was brought up with the spirit of 8-bit computing, where anyone could spend a day or two locked up in their bedroom coding a game, the current climate is all a little disconcerting. Take Watch Dogs: this is a big game that a big publisher is making, that before it’s even been released has been put on the fast track for a bigscreen movie. Or the evil of Candy Crush Saga, the mobile game revolution that doesn’t want any money off you up front, but is happy to take as much off you as it can once it’s got you cosy and sitting on the sofa. Games are interesting, and always have been, because they’re at the forefront of control. I think back to sticking dongles in the back of my Commodore Amiga to stop people pirating a game (naturally, the only people inconvenienced turned out to be the people who legitimately coughed up), or lining up pictures on wheels. Then, as technology evolved, so did the methodologies of control. PC gaming, through

n King’s Candy Crush Saga – a ruthless money-making machine


Windows, has taken things to scary levels. At one stage, the publisher Ubisoft implemented a system whereby you had to go online and prove you were legitimate once a day, else you weren’t allowed to play the title that you’d legally bought. Naturally, one day its servers weren’t working properly and people weren’t allowed to play their game. Those running pirates copies could. Microsoft has tried to implement a similar system with its upcoming Xbox One games console, although it’s had to perform a significant U-turn when the volcano of public opinion erupted. Still, those buying a game for an Xbox One machine will need to ‘activate’ it. A friendly word that, isn’t it? It sounds so reasonable and happy. Just do one thing and everything will be active and working. What could be easier? The truth, of course, is that it’s a further eradication of users’ rights in the proprietary software sector. The problem is that what happens in videogaming increasingly becomes a dry-run for what we get in the broader technology ecosystem. Publishers know that people will endure a degree of hassle to play a game, and they take advantage of it ruthlessly. Now, we’re at a point where Adobe’s Creative Suite of tools won’t even be sold in a box any more – it’s the cloud version or bust, and a subscription. Someone’s been looking at the World Of Warcraft model. Even in the app sphere, where the spirit of the bedroom programmer should still be alive and well, there’s a corporate sheen that’s taking the fun off things. That Candy Crush Saga model has proven to be the proverbial grail for many, in that the appearance of a free, open approach is just a disguise for one of the most ruthless gaming money-making machines I’ve seen in recent times. It’s why the good ones need supporting, of course. But for all the marches of progress, the loss of an ethos has become real collateral damage.

Opinion

The free software column

open source

the Free soFtware column

a Gpl breakthrough

Samsung is releasing the code for its exFAT file system driver for Linux under the terms of the GPL. This is an important breakthrough because of the participation of both Samsung and the GPL Compliance Project for Linux Developers

richard hillesley writes about

art, music, digital rights, Linux and free software for a variety of publications

non-profit Foss organisation the software Freedom conservancy has reached an amicable agreement with samsung to release the code for samsung’s exFat file system driver for linux under the terms of the Gpl. The exFAT driver code came to light through its inadvertent release via GitHub (lwn.net/Articles/560424/) and the use of a binary version in a Samsung Linux-based tablet. The Software Freedom Conservancy, led by Bradley Kuhn, works with developers and manufacturers to ensure compliance with the GPL. The greater part of the job is to point out the legal obligation to manufacturers and to help them achieve compliance, and most will happily comply.

As we all know, the GPL makes a simple pact between the coder and the user. Anyone can take, modify, copy, share and redistribute the software and the code, but must pass on the same rights to subsequent users of the software, including any modifications to the code. The coder, who is usually (but not always) the copyright holder, gains because enhancements to the code are fed back through the development process. The manufacturer gains because thirdparty developers become involved who may bring new dimensions to the code. The user gains because the code remains free and the obligation is mutual, meaning that every other user has the same obligation to feed their changes back. The only requirement of the GPL is that the source code be made accessible to end users, but this requirement is often ignored, especially when the code is reused in firmware and embedded devices. GPL code is used in thousands of devices, but many don’t comply with the terms of the licence. The role of Software Freedom Conservancy is to alert manufacturers to failures in compliance and to help them to reach an amicable resolution. Most violations are resolved without court proceedings. In very rare cases this may involve litigation but as Jeremy Allison, a board member of Conservancy, observes: “The point is not to punish people for making mistakes, but to bring them into compliance. When people get into trouble it’s usually down to laziness and inconvenience. It’s usually a case of ‘I can’t be arsed, and it’s too much effort to do it right, so I’ll just use it’.”

“Sharing the code is useful to everyone, but the terms of the GPL haven’t always been enforced”

The great majority of infringements are not deliberate, and can be attributed to misunderstandings and lack of attention to detail. Manufacturers of mobile devices operate in a rapidly changing environment with short product cycles and shorter time-to-market. The market for firmware and mobile devices is highly competitive, and every new product comes to market with a new range of features. Failure to comply with the GPL is usually inadvertent, but releasing the source code is a small price to pay when set aside the considerable advantages of cost-effectiveness, speed to market, and the accessibility of pre-written and tested code that free software offers, especially when it is remembered that it is only the GPL’d code that has to be made available to others. Sharing the code is useful to everyone, but the terms of the GPL haven’t always been enforced because the coders have other things to do, or the copyright has been assigned to corporate entities who don’t care about the licence beyond their immediate needs. For this reason it is an important development that significant contributors to the Linux kernel, in the shape of Conservancy’s GPL Compliance Project for Linux Developers, have become involved in helping to ensure compliance with the terms of the licence, and that Samsung, a major manufacturer, was not only a willing and amicable partner in releasing the code, but was happy ‘to talk publicly about the matter’, which may make it easier to achieve compliance from other manufacturers in the future. The drawback, in this instance, is that exFAT is owned by Microsoft, is a proprietary file format and has patent issues. The exFAT driver code can only be deployed by manufacturers or distributions that have obtained a licence from Microsoft.


OpenSource

Your source of Linux news and views

JOn MaSterS

the kernel column The latest developments in the kernel community, including changes to Linux 3.11

Jon Masters is a Linux kernel hacker who hasbeen working on Linux for some 18 years, since he first attended university at the age of 13. Jon lives in Cambridge, Massachusetts, and works for a large enterprise Linux vendor. He publishes a daily Linux kernel mailing list summary at kernelpodcast.org

Linus torvalds announced the latest release candidate of the 3.11 ‘Linux for Workgroups’ kernel on the 22nd anniversary of his original ‘Hello everybody’ email first introducing Linux back in 1991. The last few weeks have been largely quiet in terms of changes merged into the mainline kernel, typical both of late summer and of the late stages in a kernel release cycle. It would seem that temporary fixes for the ongoing Windows 8 ACPI compatibility issues – which cause display backlights (now managed directly by certain Windows graphics drivers, rather than in the ACPI firmware) to misbehave on some laptops – will suffice for this release, but will be


raised again in the next cycle. If all goes according to plan, the final release should be out very shortly, in time for a summary in next month’s issue of Linux User & Developer. Every Linux release has a (code) name, typically something very silly, and usually whatever Linus dreams up at the time he opens the merge window (the period of time during which disruptive kernel changes are allowed) for a new kernel release. But from time to time, a release name has a deeper meaning. The 3.11 release came close to happening on the 20th anniversary of the original Windows 3.11 ‘Windows for Workgroups’ release, but it was not to be. Still, Linus had some fun with the celebration of the 22nd anniversary of his original Linux announcement, posting a Google+ post in which he parodied himself, saying: “I’m doing a (free) operating system (just a hobby, even if it’s big and professional) for 486+ AT clones and just about anything else out there under the sun. This has been brewing since 1991, and is still not ready.”

nUMa development

Linux Weekly News recently noted that there can often seem to be themes to given periods of kernel development, and that this past month has had somewhat of a memory management theme. This certainly seems to be the case. But even more specifically, this month’s theme would seem to actually be that of NUMA (NonUniform Memory Access) development. NUMA is all about dealing with the reality that as SMP (symmetric multiprocessing, the kind used in

your computer to provide many CPU cores for the operating system) scales, it does not necessarily do so in a linear fashion. The truth is that certain memory DIMM banks are ‘closer’ to certain CPU cores. In an SMP system, every CPU can access every memory location in the system, which is typically ‘coherent’, meaning that the underlying hardware takes care of ensuring that memory locations cached internally by other CPUs are updated when a different CPU updates that same memory. But accessing a given memory location can be more expensive in terms of latency if it is not ‘local’ to a given processor – ie if the underlying hardware must take more steps to reach a given location by routing access to that location through an inter-processor local bus. To an application (and a user) this manifests in terms of slower performance than could be achieved if the memory for an application were strictly local to a given processor. Linux handles NUMA in various ways. To a certain extent it can provide a level of transparent support, by ‘migrating’ memory for applications to be closer to the processors that are using it (copying the underlying memory locations to other locations more local to a given processor and updating the virtual memory translation tables accordingly), but special tools have been written to allow administrators to be more specific about how a given application should manage its memory. Mel Gorman, famous for writing the definitive book on Linux memory management, has been working on NUMA scalability problems recently, and both he and

Opinion

The kernel column – Jon Masters

open source

“This month’s theme would seem to actually be that of NUMA” Johannes Weiner have posted patches that aim to better handle NUMA hinting and automatic reconciliation of memory closer to where it is used. Beyond NUMA, other memory-scalabilityrelated topics were discussed at length over the past month. Dave Chinner posted patches that convert the kernel inode cache (an internal kernel data structure responsible for caching metadata about mounted file systems) to use Paul McKenney’s famous (and IBM patented) RCU (read-copy-update) memory access optimisation. This allows the inode cache to scale more easily when Linux is run on very large NUMA or non-NUMA systems without using a previously global lock. Also scale related, Andy Lutomirski (of a large banking corporation) began a discussion concerning a new MADV_WILLWRITE flag that can be used when setting up memory mappings to inform the kernel that a given range of virtual memory will definitely be written to later. This allows the kernel to forgo its usual ‘copy on write’ (deferred allocation of new virtual memory regions until the first use) and instead take the (slightly more expensive) up-front hit of directly allocating the memory in order to save a latency hit later when that memory is touched by a running application. Memory management contributions this month also included a virtualisation optimisation from Martin Schwidefsky (of the IBM s390 team), who provided patches that allow guest instances to inform a host hypervisor that they are not using pages (the fundamental unit of memory chunks that the system uses to manage memory used by applications, virtual machines, the kernel itself and so on), which are automatically discarded whenever they would be swapped out to disk, and reinitialised when required later. Still further in the realm of memory management, Michal Hocko provided a patch that prevents the OOM (out of

memory) killer from being triggered on kernel allocation faults – the kernel should itself be able to handle memory allocations failures, or use dedicated reserve memory pools.

power capping framework

Beyond memory management, Srinvas Pandruvada (Intel) posted an initial RFC (Request for Comments) patch – the first stage in developing a new idea into code – series that implemented an in-kernel power capping framework. The basic idea is to allow a given system (platform) to specify how much power is available and for a precise cap to be enforced across a variety of CPU and non-CPU devices installed within the system. Using this mechanism, it is hoped to provide certain limits (such as the amount of power that can be delivered by a battery, or power utility, or the amount of power available if a battery is intended to last for a certain time period, and so on) and for devices to provide various performance tradeoffs within those constraints. But by providing an overall framework, it is possible for the kernel to make whole-system decisions that are not isolated to a given subsystem or to a given device in isolation. Initial comments on the power capping framework were favourable, although Greg Kroah-Hartman (now of the Linux Foundation) suggested that he wanted to see actual users of the framework before it is merged – by which he meant that he really wanted to see Intel post code for its own CPUs and platforms to make use of this framework. This seems to be in progress, since comments on the mailing list implied that such patches exist and have been reviewed by at least a subset of developers to this point. It will be interesting to see where this development leads, especially in the mobile space, and also when applied to other architectures.

ongoing development

Beyond NUMA and virtual memory, development has included an initial implementation of UEFI boot stub support for 32-bit ARM systems (which previously used a less standard embedded bootloader called U-Boot), a patch to allow perprocess control of transparent huge pages, a fix for PCIe reinitialisation when performing a kernel crash dump (and kexec into a kernel that must not have outstanding DMA operations pending on boot), and optimisations from Andi Kleen for the kernel build system known as kbuild. Andi’s patches convert the ‘kallsyms’ stage of kernel compilation into a single-pass, rather than being the multi-stage process that has been the case. This is the point during kernel compilation at which all of the symbols (function names provided by the kernel for internal and modular use) are resolved during the final linking of the kernel image. Andi has a series of cute hacks proposed for dramatically speeding up the process. In this month’s kernel announcements, Ted Ts’o reminded everyone that the 2013 Linux Kernel Summit is coming up in Edinburgh next month, and that there will be places reserved for those who are strictly hobbyist developers. This seems to have been a late decision since the deadline for submissions came and went quickly, but it will be worth keeping an eye on this next year, in case such an invitation is repeated. Beyond the Kernel Summit, there will be a number of kernel and nonkernel developers present at the Linux Plumbers Conference in New Orleans, at which several other mini-conferences will run concurrently. These include an ACPI/Power Management gathering, a PCI mini-conference and this year’s Linux Security Summit, among many others.


Feature

Android Studio

Get started with

Android Studio Get your head around the early access preview of the next stage in Android development

A

nnounced earlier this year at Google I/O, Android Studio will be the replacement for the current Android development solution in Eclipse. This Eclipse setup is part of the Android Developer Tools, and takes advantage of the IDE’s Java-based development environment and plug-in support to currently create the development portion of Android apps. With the rest of the SDK, virtual devices can be created and used to test code before deployment onto real devices. The Android Studio aims to be an all-in-one solution for development and testing. Coming with the entire SDK, and not even requiring traditional compiling or installation on Linux, Android Studio is an incredible easy and quick way to get straight into coding your apps – whether you’re an experienced Android/Java dev working directly in code, or a novice looking to use the graphical, drag-and-drop approach to app creation. Android Studio is still currently in beta as a free early preview – we’ll cover some of the current quirks with the software. However, it’s a definitely a great way to get used to using the software before the final switchover occurs. We’ll also cover how you can export from Eclipse if you’ve already been using that, and how to then distribute your app once it’s finally complete.


Android Studio

Get to grips with the new IDE for Android development

Feature


Feature

Android Studio

Introducing Android Studio The new Android Studio is based on IntelliJ IDEA, a much smaller and streamlined IDE than Eclipse. Android Studio utilises its features to create an all-in-one Android development environment with a smart visual view that is great for people just getting into app development, and the standard text editor for those who know their way around Java and the Android API.

Installation is very simple as well – the files contain both the IDE and the SDK you’ll need to create your apps, so you won’t need to install the SDK via ADT separately like you will have done with Eclipse if you’ve developed for Android in the past. The Studio allows you to edit how the SDKs are utilised, how imports and exports work, and even has a plug-in manager.

■ New Project Start a new project by going through the handy Android new project wizard, selecting API levels and setting the icon ■ Recent Projects The recent projects view allows you to go straight into any project you wish to work on without having to look in the Open Project prompt

■ Docs and How-Tos Some tips and how-tos for IntelliJ, the base of Android Studio, are available straight from the welcome screen

■ Check for updates

Android Studio has its own update manager, allowing you to keep it up to date. It will notify you when a newer version is available

Installation

01

Download

Head over to the Android Developers website and grab yourself a copy of the early access preview to Android Studio from here: bit.ly/1bWrFXz You’ll need to then extract the contents – put it in a folder you have easy access to, as you need to run the Studio from the folder.


02

Runtime Use cd in the terminal to navigate to

03

the folder you just created, specifically the First run android-studio/bin/ directory. To launch If this is your first time using Android Android Studio, enter into the terminal: Studio, you can safely ignore the prompt to import any settings. Otherwise, find the $ ./studio.sh If it asks about your Java settings, for file you created from before, or your old now press Enter, as we can fix that later if it installation folder, to get previous settings. We can import from Eclipse later on. becomes a problem.

Android Studio


FEATURE

Helpful shortcuts

Key features

Android Studio has handy, configurable keyboard shortcuts. Here’s a list of the most common to get you started…

Development views As the Java for the Android apps is split into visual and function elements, you can use a visual WYSIWIG editor for the XML code, allowing you to place buttons and text and other UI elements wherever you want on the screen. The text part is a full IDE, with code navigation, debugging, syntax highlighting and a smart code analyser that warns you of any obvious issues with what you’ve written.

Command look-up (autocomplete command name)

+

Ctrl

+

Shift

A

Project quick fix

+

Alt

Enter

Reformat code

+

Ctrl

+

Alt

L

Show docs for selected API

+

Ctrl Virtual devices Test your apps on a virtual device that you define, either by using settings for the main Nexus devices, or by using generic settings for differentsized Android phones or tablets. You can edit the system settings to limit or increase RAM, and even allow it to use the system GPU if you need it to. It’s not perfect, but it’s a great way to quickly test functionality.

Q

Show parameters for selected method

+

Ctrl

P

Generate method

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Build

Eclipse migration

Debugging

For existing Android developers, it’s easy to migrate from Eclipse and the ADT to Android Studio. The tools are already in place to export the necessary files from Eclipse, and Android Studio includes a handy feature that allows you to then import them, and any other Studio file. This is helpful now and will be essential when it replaces Eclipse.

A specific debugger can analyse the code as it runs and give you a full rundown of what’s happening when, allowing you to go through the logs and figure out any possible issues, or work out where problems are already occurring. You can pause the program at any point to isolate issues, instead of having to search through code as it continues to run.

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Feature

Android Studio

FAQ

Since Android Studio is still under some development, there are some bugs that still need to be ironed out. Here are a couple of known issues with Android Studio that you can work around.

Create a new project Android Studio offers a quick way to start your app: name, package name, theme, advanced icon options and the ability to select between different Android APIs. The latter allows you

to put together an app with specific versions of Android in mind, making newer API objects available for some. We’ll look at a basic setup first so we can make our Hello World app later.

01

Create New Project

02

Set image

03

Activity selector

04

Activity name

05

Project structure

06

Views

1) Error: Gradle project refresh failed Android Studio has a newer version of Gradle that has some backward compatibility issues. These can be fixed by first clicking the link to search build.gradle from the error dialog. From there, doubleclick the line under the build.gradle usage, opening the project build.gradle file. Edit the classpath to change the gradle version to “0.5.+”. Finally, save the file and rebuild your project. 2) Error: Failed to import Gradle project This can be a problem after upgrading Android Studio, as the project files may point towards an SDK element that no longer exists. To fix this, you’ll need to quickly install the Android Support Repository. First, open Android SDK Manager, find and expand Extras, and install Android Support Repository.

From the Welcome screen, click on Create New Project to open up the dialog window. Name the project HelloWorld – we’ll be creating the code for that shortly. Leave all the other default settings – they relate to what versions of Android will be able to use the app.

For now, we’ll just use the blank activity. When making other apps, this activity selector can help you choose how the app with behave – such as being full-screen or having a multi-column flow to view several items.

Here you can set your image, giving you a nice preview of how it will look on different types of devices. You can set padding, background colour and more to your app icon. For now, click Next, as we don’t need an icon for the sample project.

Here you can name the activity and customise the way it works, with tabs, dropdown menus and other actions. For now, we’ll leave this as is. Hit Finish and the project will be built. It may take a little while to do this.

Migration

It’s quite easy to export existing projects from Eclipse and then import them into Android Studio. First of all, make sure your ADT plug-in is up to date, then select File and Export. Open Android from there and select Generate Gradle files, then your projects to export before clicking Finish. In the basic Android Studio window, click on ‘Import project’, find the build.gradle file and then press OK at the pop-up. You should then be able to start development on the project within Android Studio.


Android Studio will create a lot of files for what will be a simple app – luckily we just need to pay attention to MainActivity.java and Main_Activity.xml for the moment. The interface is also initially set up to allow for WYSIWYG visual development.

The default view is the visual development interface – it includes elements down the side that allow you to drag and drop functionality. You can also click the Text tab at the bottom to get straight into the Java code, with a live preview updating as you type.

Android Studio


FEATURE

A view to develop The two views for Android Studio serve different purposes – and people. The default visual view allows you to drag and drop functions onto the interface, with guidelines to make sure you keep them aligned with other UI elements. This then adds the elements to the code, so you can edit them further in there.

■ Layouts & widgets Drag and drop different layouts and functions to create your app visually – a great way for novices to get started

■ Live preview See a live preview of the way your app will look, even while using the text mode

The text view works like any good IDE, with a hierarchical view of code, code navigation tools, autocomplete and, of course, proper syntax highlighting. Whichever view you use is up to you – however, you will ultimately have more control with the text view.

■ Toolbar Quick access to preview and debugging tools, along with the ability to change the theme, activity type and the device preview

■ Component tree Even in the visual view, you can break down the code in the individual components to see how they work

Useful resources There are plenty of online resources you can use to help you with your development – whether you need to figure out a more elegant method to create a specific function, or need to wrestle with some bugs. Here’s a list of some of the places you should visit. Android Developer Site – developer.android.com As well as the place to get Android Studio, the

Developer site has regular posts on interesting projects, updates to the SDK, and some troubleshooting tips.

Support for IntelliJ IDEA, the base for Android Studio. Some of the support questions may be more suited to the IntelliJ side of things.

Stack Overflow – stackoverflow.com

XDA Developers – www.xda-developers.com/

One of the best places on the internet to get advice on an issue – either by searching for a related question or submitting your own. IntelliJ IDEA Support – intellij-support.jetbrains.com/home

A community built around smartphone development, the XDA forum is a good way to find out about Android-specific tips and tools, and even to promote your application.


Feature

Android Studio

Make your first application Creating your first app in Android Studio is easy, and we’ll start with the simplest one of all – the classic Hello World. All basic apps, when created, have Hello World already displayed

01

Visually

To do it visually, simply select Plain TextView, and place it on the display. Doubleclick it and type in ‘Hello World!’. All static text can be placed this way onto the interface, and it will create the necessary code in the text view as well.

02

Relative text

android:layout_height=”wrap_content” android:text=”Hello World!” android:id=”@+id/textView”/> The layout variables can also be set as fixed pixel width/height.

04

Quit button

05

Imported

The file we’re editing now is just the display. To do something, we need to start editing the .java file. While we’re still in the .xml, place a button and give it the caption ‘Quit’. Open up MainActivity.java from the Projects column before we continue.

The relative layout should be included in the code by default. Create a text parameter by opening up triangle brackets with:

03

Hello code

To add ‘Hello World’ to the Text parameter, we put in:

within them – what we’re going to do here is learn how to simply make Hello World in Android, and what other simple tasks we can do in it.

android:layout_width=”wrap_content”

Now add these imports to the top of the code:

import android.view.View; import android.view.View.

OnClickListener; import android.widget.Button; This allows us to use some extra Android functions to press and use the Quit button.

06

Coded actions

Add the following code below the line “setContentView(R.layout.activity_main);”:

Button button = (Button) findViewById(R.id.button) button.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { finish(); System.exit(0); } });

Code listing ■ Package name The name of your package according to the Android system

■ import functions Import the various functions we need to get the code to work on an Android device ■ MainActivity class The MainActivity class includes all the functions in our main activity that we created ■ Main layout This sets what the main layout, and displays it ■ Quit button The section containing the code to make sure our button (with id button) properly quits the app with System.exit ■ Settings menu This creates the Android settings menu that appears at the top of the app


package com.linuxuser.helloworld; import android.os.Bundle; import android.app.Activity; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; public class MainActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button button = (Button) findViewById(R.id.button); button.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { finish(); System.exit(0); } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }

Android Studio


FEATURE

Working with virtual devices

Create a virtual Android device to test and debug your Android apps, choosing from a selection of generic phones and tablets

■ Home screen Emulate a list of Android devices, from Nexus phones and tablets to generic phones defined by screen resolution

■ Physical buttons There’s a range of physical buttons you can use that work on certain devices, with power and volume working on all

■ Hardware specs Edit specific hardware variables to better emulate certain aspects of a device, or give it more power via your host system

■ Android buttons Software buttons are included on the virtual device, as they are part of modern Android

01

Virtual device manager

From the Project View, find the Android Virtual Device (AVD) manager icon along the top and click it. From here you can create and edit a range of devices for testing your apps on. Click on New so that we can get started.

02

New device

In the pop-up dialog, name the virtual device, select the device you wish to emulate and then the target API level. Some devices will have a minimum Android version target. Your can edit this later, but for our app we won’t need to change any other settings.

03

Virtual reality

Click OK and Android Studio will confirm the options you’re using. Press Start while the device is selected and choose whether you want to get a pixel-accurate screen, or a scaled version. It will then boot up a virtual phone or tablet you can test on.

Debugging

Android Studio includes tools to debug the apps you create. To use them, first make sure a device is running to emulate the app. Then, click the Debug button – in the shape of a green bug – and the file will rebuild and launch on the device. This time, though, it will bring up a full logging window, a console and a debugger with full tools to figure out where problems may be occurring in your apps.

■ Use Android Studio’s debugging tools to analyse your code


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Tutorial

Make a small business database with LibreOffice

phpMyAdmin offers a web-based front-end for the creation and maintenance of MySQL databases

Data entry is carried out via an easy-to-use form in Base, the front end to our database

All of the actual database design (fields, form layout etc) is carried out from within Base

You import and export data to and from LibreOffice Base by using Calc, the spreadsheet module. This enables access to most common data formats


Create a database that combines an easy-to-use, form-based front-end using LibreOffice with a portable, networked MySQL back-end Advisor

Michael Reed is a technology

writer, and he’s been hacking away at Linux for over 15 years. He specialises in desktop Linux solutions

Resources

LibreOffice: www.libreoffice.org At least one Ubuntu Linux PC


We’re going to show you how to put together a typical database for small business use: a database of customer details. It will be possible to both export and import contact data from in standard formats by making use of Calc, LibreOffice’s spreadsheet module. We’ll use Gmail contacts as our source, but you can use any software that can export CSV files – and pretty much everything can. We’ve added a few twists to keep things interesting. This project uses the Base module of LibreOffice as the front-end, and this provides a GUI for setting up the database, creating the

forms for data entry and the actual business of entering data. For the back-end, we will be using the industry-standard MySQL. This allows us to locate the back-end on a central server. This, in turn, allows multiple users to access the database. For initial creation of the MySQL database, we’ll use phpMyAdmin thanks to its friendly web interface, although the actual database design will be carried out from within Base. By the end of the project, you will have a GUI system for browsing and editing the database with a portable, networked back-end.


Use LibreOffice and MySQL to create a customer database

TUTORIAL

01

Install LibreOffice

At time of writing, the major Linux distributions haven’t moved over to LibreOffice 4 and are still offering 3.x. This means that you may have to install LibreOffice 4 manually. Visit the LibreOffice website (www.libreoffice.org) and follow the instructions. On Ubuntu, this consists of unpacking the archive and running sudo dpkg -i *.deb on the contents.

02

Install the Apache web server

03

Install Java and additional classes

We’ll install Apache early on and with its own command because some of the other packages need to be able to configure a working Apache installation. Carry out the installation with sudo apt-get install apache2. Test it by navigating a web browser to http://localhost.

04

Install the MySQL Server Type sudo apt-get install mysql-server to begin installation. Before long, you

should be prompted to set a root MySQL password. Note that this isn’t the same as the administrator account of your system, which is also called ‘root’. Choose a password and make a note of it.

05

Install and test phpMyAdmin Type sudo apt-get install phpmyadmin to begin installation. When

prompted to choose a web server, choose Apache2, select it with the space bar and press Return. When requested, give it the MySQL root password and then choose a password for phpMyAdmin and make a note of it. Navigating to http://localhost/phpmyadmin/ should take you to a functioning login page. Log in using the MySQL root username and password. We’ll use MySQL to set up and maintain the actual database, although we’ll create the fields from within LibreOffice later on.

06

Create database

07

Add JDBC in LibreOffice

Within the phpMyAdmin web interface, select the Databases tab. Now create a new database by entering the name ‘customer’ into the text box and clicking on Create. This database will contain our customer data.

We now need to tell LibreOffice where to find the JDBC class file. Start LibreOffice and go to LibreOffice>Options>Advanced. In the Java Options section, select Class Path and then Add Archive. The file you need is located at: /usr/share/java/mysql-connector-java.jar. Select it and restart LibreOffice.

Connectivity between Base and MySQL makes use of a Java class. Type sudo apt-get install default-jdk to install the Java runtime. Type sudo apt-get install libmysql-java to install the needed additional Java classes.


Tutorial

08


Connect the database

We now need to connect our frontend (LibreOffice) to the back-end (MySQL) of our database. Start LibreOffice and launch the Base module. In the dialog that pops up, select ‘Connect to an existing database’. From the dropdown menu below this, select MySQL as the database type.

09

Configure Base

On the next page, select ‘Connect using JDBC’. On the next page, click on ‘Test class’ to ensure that the Java RT is working. Now enter the name of the database that we created, customer, and enter localhost into the Server field. On the next page, add Root as the username and tick ‘Password required’. Now click on the ‘Test connection’ button and enter the root MySQL password, when asked for it, to test the connection between LibreOffice and the local MySQL server. Presuming that this completes without errors, click on Next.

10

Save the database

You can accept the defaults on the next page, so click on Finish. When prompted, give the database a name and save it. Remember that this file contains the connection information for access to our MySQL database – it doesn’t contain the actual records.

11

Create fields from a template

You may want to create a custom set of fields for your customer records, but to save time we’re going to use the one of the templates that is built into Base. Select Tables from the side menu and then ‘Use Wizard to Create Table’. Using the Sample tables pull-down menu, select Customers. Use the >> button to copy all of them across. On the next page, you can tweak the fields that you have included and add new ones. Select the defaults on the next two pages and then click on Finish.

12

Create form from template

13

Finalise form

Select Forms from the sidebar. Click on ‘Use Wizard to Create Form’ in the Tasks window. In the table wizard, click on the >> symbol to copy across all of the fields in the database.

Accept the defaults in sections 2, 3 and 4, but select the first arrangement icon in section 5, ‘Arrange controls’. You should now see a preview of our entry form in the main window. Select defaults on the other sections and then click on Finish.

Remember that this file contains 14 Test data entry the connection information for access to our MySQL database – it doesn’t contain the actual records

To enter data into the database, use the form that we created. Select Forms in the sidebar and then double-click on the name of the form in the main window. This brings up the GUI recordediting interface. The form can still be tweaked and edited by right-clicking on its name in the main window.



Use LibreOffice and MySQL to create a customer database

TUTORIal

18

align the fields

19

Create a new database user

20

Redistribute the database

The field names from our imported data don’t quite match those of the database and so we need to use the second page of the wizard to line them up. To do so, click on a field name and use the up and down icons in the other list to create the correct attachments. Then click on Create.

15

Export your contacts from Gmail

16

Clean up the data and create a key

Switch from the Gmail contacts view using the pull-down menu in the top-left corner, underneath the Gmail logo. From here, click on the More icon pull-down menu and select Export… Click on Export.

Start a new spreadsheet and open the CSV file that you exported from Gmail. Use Ctrl-mousewheel zooming to get an overview. Typically, a lot of the fields will be completely blank, so select these columns (click on the column letter at the top of the window) and remove them (Edit>Delete cells). We have to create a key for each record. Label a column ID. Select the first cell in the column and then select the final cell by Shift-clicking on it. Use the fill feature (Edit>Fill>Series).

17

Import the data into Base

When you’ve cleaned up the spreadsheet, select the data (including the column headers) by clicking on the top-left cell and then Shiftclicking on the bottom-right cell. Right-click and select Copy. Select Tables from the side menu of the Base module. From here, right-click on the customers table and click on Paste. This should bring up the import wizard. Select ‘Append data’ and ‘Use first line as column names’ options, and click on Next.

To access the database from more than one machine, you must create additional users. Log back into phpMyAdmin, click on the Users tab and select ‘Add user’. From here, create a new user with the name and password of your choosing and make a note of it. Click on ‘Check all’ in the ‘Global privileges’ section.

In the Base module, re-save the database under a new name. In this new version of the file, we have to alter a few details. Select Edit>Database>Properties and enter the name of the new database user. Click on the Additional Settings tab and enter the IP address of the machine with the MySQL database.


Tutorial

Write LaTeX documents with LyX

The toolbar gives you shortcuts for items like lists, images, tables and maths formulae

You can always see what the actual LaTeX source code looks like for your document. Nothing is hidden from you in LyX

The main window is where you type your text. This is also where your text gets rendered

You can view what your document will look like by rendering it to a PDF file. Don’t forget to refresh it after making edits


LyX lets you to get your document written without having to deal with LaTeX’s steep learning curve. Here’s how… Advisor

Joey Bernard As a true renaissance

man, he splits his time between building furniture, helping researchers with scientific computing problems and writing Android apps. When the kids let him have some time, that is

Resources

LyX: www..lyx.org LaTeX: www.latex-project.org


LaTeX is a typesetting system that gives you full control over how everything in your document is rendered. The problem is its really steep learning curve. One option is to use a basic text editor and learn all the markup you need for your document. The other option is to use an application that wraps the markup to some degree. LyX does this very nicely. While a fully WYSIWYG editor for LaTeX doesn’t make sense (since your doc isn’t fully rendered until sent to an output device), LyX does provide a pseudo-WYSIWYG interface where you can see how different regions will be rendered.

In this tutorial, you’ll learn how to create a new document and create various content sections, like images, tables and lists. You will also learn how to use various document settings, like the document class, to control the overall options used during document rendering. Since LaTeX is a typesetting system, LyX will let you output to several formats, like PDF, Postscript, HTML, plain text and OpenDocument files. Regardless of whether you are writing a book, a journal article or a set of presentation slides, LyX will help you get your work done with minimal fuss.

Write LaTeX docs with LyX

Use LyX to lay out your LaTeX documents with ease

TUTORIal

01

Installation

The first step is to get LyX installed on your system. Most distributions should have a package available. For your non-Linux friends, there are binaries available for Windows, Mac OS X, and even OS/2 and Haiku. As always, you can download the source code and build from scratch in the worst-case scenario.

04 02

Opening a new document

03

Setting the document class

When you first start up LyX, the main window opens up with a splash screen image displayed. You actually have to tell LyX that you want to start a new document before you can start writing. You can start a new document by clicking the menu item File>New.

Text layout

While the document class sets the defaults for your document, you still have full control to change anything in the document. The Text Layout option lets you change the indentation size to a custom increment. The vertical spacing and line spacing can also be customised. You also have the option to make your document two-column here.

05

Page layout

LaTeX figures out the actual rendering of your document based on a page layout. You can select one of a number of standard page formats, or set a custom page size. You can set whether the page is oriented as either portrait or landscape mode.

06

Numbering and the TOC

07

View source

Documents are broken down into several nested subregions. How these regions are handled in the layout is decided by the document class. You can also set whether these regions are numbered or not, and whether they show up in the generated table of contents. Now that your document is set up, you can start typing. LyX gives you a pseudoWYSISYG display of the text. But LaTeX is a purely text-based markup language, so you can always see the actual source code to verify what LyX is putting into your document. To see the source, just click on the menu item View>View Source.

Many of the layout properties for your document are set to defaults based on the class of your document. You can set this by clicking the menu item Document>Settings. This will pop up a dialog window that we’ll use for the next few steps. The drop-down list will give you a very full list of possible document classes.


Tutorial


Many of the layout properties for your document are set to defaults based on the class of your document

08

Title

The first item your document will need is a title. In LaTeX, you need to worry about what a particular piece of text is supposed to be, not what it will look like. So at this stage, you can type in your title text. To identify it as a title, you can click the drop-down at the top right of the toolbar and select Title.

10

Dates

11

Abstracts

You should have noticed that there is a date option in the drop-down. You don’t need to use this if you don’t wish to. LyX will automatically add the current date when you actually render the document into an output format.

If you are writing an article, or a report, you may need to include an abstract of the subject matter being covered. If you have already written your abstract, you can highlight the region with your mouse and select Abstract from the dropdown. This adds the title ‘Abstract’ and changes the format of the text.

09

Author

Hitting Enter will give you a new line, with the type back to Standard. You can here enter your name and set the type to Author, again with the drop-down at the top right of the toolbar. Where and how this will get rendered depends on the document class and the output format.


12

Sections

13

Mathematical formulae

In most documents, you will probably want to break the text down into sections, and possibly subsections. Sections are defined by giving them a title. For instance, if your first section is going to be an introduction, then you would type the section title as ‘Introduction’ and set the type in the drop-down to Section. The actual text for this section would be set to the type Standard.

Mathematical formulae are always a problem area in document typesetting. Many people in the sciences first move to LaTeX because of the ability to fully control equations by explicitly laying out all of the elements. However, for more complex equations, this can still be confusing. Therefore LyX provides an equation writer tools that helps you create the LaTeX required to lay out your formula in your document. You can set the type of maths to be either inline with your text, or to be centred and displayed on its own.

Write LaTeX docs with LyX

Use LyX to lay out your LaTeX documents with ease

TUTORIal

14

lists

15

Tables

There are several different types of lists available for your use. Both numbered and unnumbered lists are available as buttons on the main toolbar. To start a list, click on one of the buttons and start typing the first item. Hitting the Enter key will give you a new item to enter. Hitting Enter on an empty item will drop you out of the list section.

You can add a table by clicking on the menu item Insert>Table. A dialog will appear where you can set the number of rows and columns. The first row is set aside as a header for the columns, but you can change this in the LaTeX source.

(pdflatex)]. There are also other viewing options, in case you want to render your document using other methods.

16

Images

Clicking on the menu item Insert>Graphics opens a dialog window where you can select an image file to insert into your document. You can either set a scaling factor, or an explicit width and height for its display. You can also rotate your image through X degrees. You also have the option to control if and how the image gets clipped to a bounding box.

17

provided by your LaTeX installation. This is defined in the Document Settings dialog, where you can set the family, encoding and fonts to use for Roman, Sans Serif and Typewriter.

20 18

Spellchecking

19

Fonts

Most people need help when it comes to making sure everything is spelled correctly. If you want to use the system default spellchecking engine, you can simply click on the menu item Tools>Spellchecker. You can change the engine being used by selecting it in the options window.

Previewing

Now that you have a bunch of content in your document, you probably want to get an idea of what it will look like once it is fully rendered. You can get LyX to generate a PDF for viewing by clicking the menu item View>View [PDF

Output formats

Now that you have your document finished, you will want to render it to some final output format. A common choice is either PostScript or PDF. This way, you know that it will look the same, regardless of who you give it to. But you have several other options available, too. You can output to HTML, rich text, plain text or even OpenDocument.

Linux users have had problems, traditionally, when dealing with fonts. This extends to applications like LaTeX. LyX includes options that help you correctly set up TrueType fonts, allowing you to use fonts other than those


Tutorial

Unison synchronises files between computers – here we’re using the commandline version of the tool

Synchronise your files with Unison

This line indicates that Unison has nothing to sync at the moment, since no files have changed


This error message shows that there is a lock file that needs to be manually removed

The network connection is broken so Unison cannot synchronise files

Learn how to use the Unison command-line tool to synchronise files between computers quickly and reliably Advisor

Mihalis Tsoukalos has over 15 years of UNIX

system administration and programming experience and has been using Linux since 1993. He is also proficient in Oracle database administration, Cisco IOS, Cocoa and iOS programming. He always learns new things

Resources

Unison: www.cis.upenn.edu/~bcpierce/unison Two networked UNIX machines


Unison is an open source file synchronisation tool for both text and binary files. It also has a GUI, but here we’re focusing on the only the command-line version because it’s quicker and gets the job done cleanly. Unison really shows its capabilities when you are working with more than one computer and you need synchronisation across all of them. Benjamin C Pierce led the creation of Unison at the University of Pennsylvania and it started life as a research project. It can be used through the

SSH service and works equally well on both UNIX (Linux, Mac OS X etc) and Windows machines. It should be apparent that Unison was inspired by the rsync utility. Unison differs from rsync in that the latter is a mirroring tool that needs to know in advance where the willing-to-keep versions of the files are, whereas Unison is a synchronisation tool that identifies the files that have been changed since the last sync process and decides the way that the changes are going to be propagated. In short, it’s smart.


Use the Unison command-line tool to sync files between computers

TUTORIal

01

Installing Unison

Most Linux distributions have Unison as a package ready for installation so that you do not have to compile it. At the time of writing, the current stable version of Unison is 2.40.102. Note that every machine that is part of the synchronisation process must have a copy of the command-line version of Unison installed. Additionally, this copy of Unison should be located inside one of the directories of the default PATH shell variable. Assuming you’re on a Debianbased system, simply type:

having a profile file does not prevent you from adding extra command-line options (although this article will not deal much with such options). In the rare event that you have troubles working with Unison, you may run it using the ‘-debug all’ command-line option so that you can better trace and resolve errors.

Synchronising files with another computer

The remote machine declaration starts with root = ssh://. There are rare occasions – usually when the user changed a file on both computers before synchronising – where Unison will not be able to determine whether a file or directory has changed on the local or the remote server. In such situations, Unison kindly asks for your help so that it will not mistakenly proceed using the wrong version.

unison -version

03

Unison can run from the command line without using any configuration files (profiles), but using a profile greatly simplifies its use –

04

$ unison articles

To find the version of Unison you are using, just type the following command:

Unison profile files

root = /Users/mtsouk root = /tmp

Given a profile name called articles.prf that is located inside the ~/.unison directory, you can tell Unison to use it by executing the following command:

sudo apt-get install unison

02

and is located inside the ~/.unison directory. The following two lines to work on the same machine, as they do not include a remote machine:

Synchronising files on the same computer

Although Unison was initially developed with synchronising files located on different machines in mind, you can synchronise files located on the same computer using one of the following two methods: • Using localhost as the remote machine name. • Using only local directory paths for both root = lines. Your advisor prefers the second way as it does not require the SSH server be up and running. The Unison profile file is called localFiles.prf


Tutorial


07

The .unison directory

08

A more advanced Unison profile file

Most of the Unison housekeeping happens inside the .unison directory which resides in the user’s home directory. Unison keeps the following data there: • Its profile files including the default profile called default.prf. • Its backup files, if you decided to have central backups. • The status file for each used profile. • The Unison log file, should you tell it to keep one. You can put it anywhere you want but it is very convenient for it to reside there. • Unison creates lock files there, during synchronisations, which it deletes when finished. Note: It is not recommended to synchronise the whole .unison directory. Synchronising just the profiles is okay.

The contents of the advanced.prf file are as follows:

05

Running Unison using a simple profile file

Some basic things you need to know about Unison profiles are: • The default backup level is 2, which controls how many previous versions of each file are kept not including the current version of the file. So the default backup level keeps two backup copies of a file. The parameter for setting the backup level is called maxbackups. • You can tell Unison not to keep file backups by not adding any backup options inside a Unison profile file. • Unison profile files support Unicode characters. • The logfile option tells Unison to keep a log file called unison.log inside the .unison directory. • Sometimes, network problems prohibit file synchronisation, but Unison’s error messages are denoting the problem:

$ unison articles Contacting server... Connection closed by 109.xxx.yyy.zzz Fatal error: Lost connection with the server

06

Explaining the profile file

Lines starting with a # denote comments and are not processed any further. Exactly two lines must start with root =. They declare the machines (one is always the local


computer) that are going to participate in the syncing process as well as the directories that are considered the root directories for each machine. After those important declarations, the actual directories that are going to be synced are listed. In this example we have just one directory (one path = line). Its full path is /Users/mtsouk/docs/ article/working for the local machine and /home/ mtsouk/docs/article/working for the machine called linode (an IP alias inside /etc/hosts). You can have as many path entries as you want. All files are synced except the ones that match the ignore option. You can also have as many ignore = lines as you want and can use regular expressions in them. The backup option tells Unison to keep backups of all files.

root = /Users/mtsouk root = ssh://linode//home/mtsouk times = true batch = true # Log file logfile = /Users/mtsouk/.unison/ unison.log # Paths to synchronize path = code/C # Backup files backup = Name * backuplocation = central maxbackups = 3 ignore = Name {Thumbs.db} ignore = Name {.DS_Store} ignore = Path {Samples.lnk}


Use the Unison command-line tool to sync files between computers

TUTORIal

3. Copy the contents of the ~/.ssh/id_rsa.pub file from your local server into the file ~/.ssh/authorized_keys found on the remote server. One way of doing it is by executing the following command:

$ cat ~/.ssh/id_rsa.pub | ssh linode 'cat >> .ssh/authorized_keys' The next time you try to log into the remote Linux server using SSH, you will be asked for the passphrase of step 1 for the last time. From now on, you can log into the remote Linux server by just typing ssh linode:

09

Explaining the advanced profile file • The times = true line tells Unison to

synchronise modification times. • The maxbackups = 3 line tells Unison to keep the current file version plus three backups of it. • The backup = Name * line tells Unison to back up every file. • The backuplocation = central, which is the default option, tells Unison to keep all backups in a central location. If neither the backupdir preference nor the environment variable UNISONBACKUPDIR are set, the .unison/backup directory is used as the backup location. If set to local, then all backups will be kept in the same directory as the original files. • The batch = true option is a little tricky and you should be careful with it as Unison will ask no questions at all and non-conflicting changes will be propagated whereas conflicts will be skipped. Nevertheless, it is an essential option if you want to use Unison as a cron job. • The ignore = Name {.DS_Store} line tells Unison to not synchronise files that end with .DS_Store.

10

Using SSH without giving a password

The single most time-saving thing you can do is to set up SSH so that you will not need to enter your password each time you want to synchronise your files and directories. The procedure is easy and involves the following three steps: 1. Run ssh-keygen -t rsa You will have to enter a passphrase twice, so please do remember the passphrase! Two new files are going to be created: ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub. 2. You may need to create a directory called .ssh on the remote server if it does not already exist.

$ ssh linode Linux (none) 3.9.3-x86_64-linode33 #1 SMP Mon May 20 10:22:57 EDT 2013 x86_64 . . . Last login: Wed Jul 31 18:46:23 2013 from ppp-94-64-21-97.home.otenet.gr mtsouk@li140-253:~$ The first time you log into the remote server without typing your password, the following informative message will be on the screen:

Identity added: /Users/mtsouk/.ssh/ id_rsa (/Users/mtsouk/.ssh/id_rsa)

11

12

Unison hints and tips

The first two or three times you use a new profile, double-check if everything works as expected. • You do not need to use every parameter that Unison supports, just the ones that will do your job! • You can troubleshoot Unison using the -debug all command-line option. It will generate lots of output useful for debugging. • The more you use Unison, the more you will understand its practicality. • You should be very careful with your backup options, especially maxbackups, as it can take up too much space on your computer. • You can use Unison to securely exchange files between computers. • If a Windows machine is involved in the synchronisation process, be careful with file and directory permissions. • For non-critical data files you may run Unison once a day, but for critical data you should run it more often. • Unison cannot replace regular backups! • When you are making a new profile, either start simple or use an existing one as a starting template. Add the extra functionality and features while making sure that you always have a working profile.

Two common Unison troubleshooting techniques

There are times when things do not work as expected. Unison offers you many options that can help you both find and solve problems. The first option to try is the -testserver option that just connects to the remote server and then exits without synchronising any files. The second thing to do is run the following command:

$ ssh $PATH'

remote.machine.domain

'echo

The aforementioned command let you see whether the PATH is the same as when you log in using ssh remote.machine.domain. If the problem is with the PATH, check if the option PermitUserEnvironment in /etc/ssh/ sshd_config is set to ‘no’ and change it to ‘yes’.


Tutorial

Browse privately with Onion Pi

This isn’t a hardware hack – a spare SD card can be used for the Tor router, and other SD cards can be used for different functions without any problems

Using not much more than a Raspberry Pi, you can route one or more systems through a Tor-enabled access point, guaranteeing anonymity


Hook into the internet just about anywhere there’s an internet connection – a relative’s house, hotel rooms and more

Turn your Raspberry Pi into a highly secure and very portable router to keep your system safe and your browsing anonymous, wherever you are Advisor

Rob Zwetsloot models

complex systems and is a web developer proficient in Python, Django and PHP. He loves to experiment with computing

Resources

A Raspberry Pi Raspbian: www.raspberrypi.org/downloads Compatible Wi-Fi adaptor: www.adafruit.com/products/814


We showed you in issue 129 how to turn your Raspberry Pi into the ultimate portable wireless router, requiring very little power and giving you a wireless network wherever there’s the most basic of internet connections. What if it’s not enough to know you can search the web, though? What if you want to be wholly secure as you do it? Then it’s time to upgrade the router with Tor to protect your privacy on the internet. This ‘Onion Pi’, as dubbed by Adafruit, combines Raspbian and

Connect everything over a wireless network – no need to directly connect to the Pi with a cable

Tor to create and secure a wireless access point using just a Raspberry Pi. This project is fairly straightforward: after setting up the wireless access point, we install Tor and do some basic setup tasks so that it routes traffic properly, and securely. This will keep you anonymous online – a handy feature in a time of privacy concerns all around the web. When the Pi is not connected to the internet, it should still function as a wireless router, allowing at the very least a wireless LAN in your location.


Turn your Raspberry Pi into a Tor-enabled wireless router

TUTORIAL

06

Set up DHCP

Now we need to configure the DHCP server. Edit the configuration file with:

$ sudo nano /etc/dhcp/dhcpd.conf And start by putting a # in front of the two option domain-name entries, then remove the # in front of authoritative, seven lines down.

07

Server address

At the end of the configuration file, add the following:

01

Install Raspbian

Raspbian is the Raspberry Pi distro we’ll be using for the Onion Pi. Download the zip file, extract the image and then apply it to an SD card using:

$ dd bs=4M if=[version number]wheezy-raspbian.img of=/dev/[SD card location]

Plug your USB wireless adapter into the Pi and turn it back on. On another computer connected to the same network, open a terminal or type into the command line:

subnet 192.168.42.0 netmask 255.255.255.0 { range 192.168.42.10 192.168.42.50; option broadcast-address 192.168.42.255; option routers 192.168.42.1; default-lease-time 600; max-lease-time 7200; option domain-name "local"; option domain-name-servers 8.8.8.8, 8.8.4.4; }

$ ssh [user]@[IP address]

Save and exit.

04

SSH connection

Then enter the password for your Raspbian if it asks for it.

You can also use NOOBS to install Raspbian if you wish.

02

Set up Raspbian

Go through the initial Raspbian setup and make sure to turn on the SSH server, and to disable autoboot to desktop – this is unnecessary and will only use extra power. You can also tell it to fill up the rest of the card if there’s room for it.

03

Pi IP

We’ll be accessing your Raspberry Pi via SSH to set it up. To do this we need to know its IP address – you can find it by typing ifconfig into the command line. Make a note of it and turn off your Pi.

05

Install DHCP

To make life easier for any system connecting to the Pi access point, we need to install a DHCP server to it. We do this with:

$ sudo apt-get install hostapd iscdhcp-server DHCP will automatically assign IP addresses to network-attached devices, meaning you won’t need static IPs.

08

DHCP server

Edit the server configuration files so that it’s set to work in conjunction with the wireless adaptor:

$ sudo nano /etc/default/isc-dhcpserver Scroll to INTERFACES and change it to:

INTERFACES="wlan0"


Tutorial

09


14

Incoming Wi-Fi

We need to set up the Wi-Fi adaptor to be both static and accept incoming signals. First:

Network addressing

Setting up a NAT will allow multiple clients to connect. To do this, run:

$ sudo nano /etc/network/interfaces

$ sudo nano /etc/sysctl.conf

Put a # in front of iface wlan0 and following lines with wpa roam, iface default and any other affecting wlan0.

And add to the bottom of the file:

net.ipv4.ip_forward=1 Save this, and then finish by running:

$ sudo sh -c "echo 1 > /proc/sys/ net/ipv4/ip_forward"

10

Static IP

Now give the wireless interface a static IP – after the line allow-hotplug wlan0, enter the following:

iface wlan0 inet static address 192.168.42.1 netmask 255.255.255.0 Save and exit, and then set wlan0’s address with:

$ sudo ifconfig wlan0 192.168.42.1

12

WLAN configuration interface=wlan0 driver=rtl871xdrv ssid=[access point name] hw_mode=g channel=1 macaddr_acl=0 auth_algs=1 ignore_broadcast_ssid=0 wpa=2 wpa_passphrase=[password] wpa_key_mgmt=WPA-PSK wpa_pairwise=TKIP rsn_pairwise=CCMP

13

Hostapd

After saving and exiting, we need to edit hostapd to point it to this new file. Open it with:

$ sudo nano /etc/default/hostapd

11

WLAN creation

We need to create a new file that holds all the information for our wireless network. We are going to make it password protected so that only the people we want to can access it. To create the file, start with:

$ sudo conf

nano

/etc/hostapd/hostapd.

And then enter the text from the next step.


15

IP tables

Run the following three commands to make sure the internet connection is forwarded correctly:

sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE sudo iptables -A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT sudo iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT

16

Apply configuration So that this still works after a reboot, type:

And then find the line #DAEMON_CONF="". Remove the #, and change it to:

$ sudo sh -c "iptables-save > /etc/ iptables.ipv4.nat"

DAEMON_CONF="/etc/hostapd/hostapd. conf"

Then add to the end of /etc/network/interfaces:

up iptables-restore < /etc/iptables. ipv4.nat


Turn your Raspberry Pi into a Tor-enabled wireless router

TUTORIal

17

Wi-Fi final

Finally, set it up as a daemon so it runs at boot with the following commands:

sudo service hostapd start sudo service isc-dhcp-server start sudo update-rc.d hostapd enable sudo update-rc.d isc-dhcp-server enable And the wireless access point part will be finished.

18

Install Tor

After a reboot, we now need to install Tor. Do this simply with:

$ sudo apt-get install tor Once it’s installed, you’ll need to edit the Tor config file with:

$ sudo nano /etc/tor/torrc Follow the next step to add all the necessary information to it.

19

Tor configure Put this below the FAQ comment:

Log notice file /var/log/tor/ notices.log VirtualAddrNetwork 10.192.0.0/10 AutomapHostsSuffixes .onion,.exit AutomapHostsOnResolve 1 TransPort 9040 TransListenAddress 192.168.42.1 DNSPort 53 DNSListenAddress 192.168.42.1

If you want to keep SSH open to connect remotely, you’ll need to make an exception for that with:

$ sudo iptables -t nat -A PREROUTING -i wlan0 -p tcp --dport 22 -j REDIRECT --to-ports 22

21

$ sudo sh -c "iptables-save > /etc/ iptables.ipv4.nat"

23

logging

We should create a log file in case you need to debug later. To do this, use these three commands:

$ sudo iptables -t nat -A PREROUTING -i wlan0 -p udp --dport 53 -j REDIRECT --to-ports 53

$ sudo touch /var/log/tor/notices. log $ sudo chown debian-tor /var/log/ tor/notices.log $ sudo chmod 644 /var/log/tor/ notices.log

And then route any TCP traffic with:

You can also check it with:

$ sudo iptables -t nat -A PREROUTING -i wlan0 -p tcp --syn -j REDIRECT --to-ports 9040

$ ls -l /var/log/tor

Reroute Route all DNS traffic first, using:

24

Secure the router

Finally, we can activate the Tor service so that we can start using the access point securely with:

$ sudo service tor start You can check this if you wish with:

$ sudo service tor status

20

Table flush

We now need to flush the current IP tables so that we can get the routing to go through Tor. First of all, do:

$ sudo iptables -F $ sudo iptables -t nat -F

22

Check and save You can check the table setup with:

$ sudo iptables -t nat -L

To make it turn on at boot, you simple add it to rc.d with:

$ sudo update-rc.d tor enable

If you’re happy with it, save it to the NAT file like before with:


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The only Linux magazine for open source developers 100% FOSS focused » Features » Tutorials » Sample code

If it wasn’t open source, if it wasn’t GPL, there wouldn’t be the 20,000 plug-ins that have been written for it

Mark Little talking about WordPress

51

■ Mike Little celebrates receiving his outstanding contribution award

The other half of WordPress

With ten years under its belt, WordPress has firmly cemented its place in the hearts of bloggers. But what next for its co-founder Mike Little? David Crookes finds out… We are on a tram to Manchester, tapping away on our phone as we update one of our blogs, engrossed in the words and thinking little about the underlying code which is making all of this possible. Just as the last few words are written, the tram stops and we make our way up the escalator to Piccadilly Station about to meet the man who created the behemoth that is WordPress, the very blogging platform we had been using throughout the journey. Our meeting is being held at a railway station because Mike Little, who is from Stockport, is a busy man. He has already had one meeting before we shake hands and he is due to have


another. We decide to sit in a coffee shop and he grabs a sandwich before telling us about his latest venture, which is – unsurprisingly given the software is used by 18.9 per cent of the top 10 million websites – very much related to WordPress. Little is currently working on a series of screencasts which showcase how WordPress can be used, explaining the fundamentals of it to encourage more people to get involved with blogging using the platform. It’s a slow process – “it takes about an hour to edit a minute’s footage,” he says – but he’s getting there. The idea is that the screencasts will form a paid-for online course. “I want them to be better than anything else that is out there, so they have to be done right,” he says. “There is a lot of rubbish

being made where you get someone just filming what they are doing and there are lots of ums and ahs and backtracking. My screencasts won’t be like that and people will certainly get value for money.” Little, who also teaches WordPress to classes face-to-face, continues to work with WordPress for professional clients too. After all, if he cannot produce a killer website for companies and organisations using the software, then nobody can. It is fitting, then, that he has worked with Downing Street on government sites. He appears most proud of a science-engagement site for children called I’m A Scientist, Get Me Out Of Here, which has spun off into I’m An Engineer. “I really enjoy doing these,” he says, explaining that his entire freelance


The story of WordPress co-founder, Mark Little

LITTLE AND LINUX

■ Matt Mullenweg’s WordPress.com website is run by his company Automattic

career has been based around WordPress since he left full-time employment in 2008. WordPress has, therefore, shaped his life. In between mouthfuls, he tells us all about the WordPress project, barely pausing for breath, and there is little doubt that he is proud of the part he played in the initial years of WordPress’s inception. If there was any doubt, then the snazzy WordPress T-shirt he’s wearing at our meeting certainly puts paid to that.

domain that was up for renewal. Another programmer, Matt Mullenweg, also used b2/ cafelog, or, as it was more commonly known, b2, and he was concerned not only about Valdrighi’s disappearance but also about the lack of development of b2. He posted an article on his blog called The Blogging Software Dilemma which discussed how he had come to be using b2, primarily because it was the best of the bunch and something he was able to develop. Mike Little spotted this blog post and responded, asking Mullenweg if he would be interested in forking b2. Mullenweg said he would. The pair then got together, albeit remotely over the internet. “I’d communicated with Matt a couple of times before because he had a website with a really good gallery on it and I’d emailed him to ask him about the software,” recalls Little. “I’d actually communicated with him on the b2 forums as well, but I didn’t know he was the same person as the one who ran the gallery site. So when I saw his blog post about b2, I was interested. As it turned out, I was the only person who responded to his posting at the time.”

66%

Proportion of all WordPress sites that are in English

Before WordPress

Little has been programming professionally since 1990. His first six years were spent at an industrial software house called Pantek in Stockport, where he became responsible for a team of six and developed Visual Basic apps, learned C++ and gained experience in DOS, Windows SDK, assembler, Novell, TCP/IP and Microsoft networks. After leaving Pantek, he went on to work at various other software companies in the Greater Manchester area, but he was also an early blogger. He used software called b2/cafelog which had been written by Michel Valdrighi, the first Corsican blogger. A small community had built up around the software with around 2,000 active users on the forum, but development of b2/ cafelog suddenly ground to a halt when Valdrighi disappeared, leaving behind an app that had a few bugs, a couple of security issues and a

Version one

Mike Little is a long-term user of Linux. “I’ve been into Linux since the early days,” he recalls. “I could see that the openness, the ability to look at code, to modify [it]… was making better software… So I’ve always been passionate about it and I just absolutely think it’s the right thing to do.” He has fond memories of the days when Linux needed to be downloaded from FTP sites and stuck on several 3.5-inch floppies. “I’m going back to 1.something series kernels, so right from when there probably were only three or four distributions. Slackware was one but I don’t even think the likes of Debian had started in the early days. I remember Red Hat starting so I was into it before that.” Little had been involved in a project called DJGPP, which was a port of the GNU Compiler Collection onto 16-bit DOS. It is, he concedes, a ridiculous undertaking in hindsight, but it meant developer tools could be obtained on DOS without having to shell out money. “I think that was before I even got the world wide web, so at that time I had a modem but I was dialling up to bulletin boards… and getting software that way,” he explains. “And then when I got onto the internet I just kind of continued in that vein. So I’d already understood that this DJGPP was a port of these GNU tools so… I started looking at what they were and how I could use those and eventually got brave enough to partition my Windows machine and get Linux booted on that. Before that I used to boot it from a floppy… but yes, eventually I went over to dual booting into Linux and in 1998 I went over at home full-time to Linux… By the time I had a decent laptop, I started with Debian but my last three laptops have run Ubuntu.”

“That first release of WordPress had a couple of extra features I’d already created for b2”

Mullenweg and Little took the b2 software and began to work on it, fixing bugs and adding extra features. Then Valdrighi reappeared. He


declared Mullenweg and Little’s software as the official successor to b2. “It turns out he’d been made redundant or something like that, had to give up his flat, gone back to his parents who didn’t even have internet and so on,” smiles Little. “So it was just the real world was much more important than a bit of software.” WordPress was thus born. It was January 2003. Little had been learning PHP and he felt he would work his way around b2 and make alterations. “No software is perfect, so it was just a case of thinking of things that we wanted to add to it,” says Little. “That first release of WordPress had a couple of extra features that I’d already created for b2 and the same for Matt: he’d had a couple of extra features that he’d added to b2. We’d shared these things on the forums and we kind of incorporated those into the core project. And yeah, we just took it from there.” One of the biggest changes was the introduction of Pages, which made a massive difference to WordPress and set it apart from its rivals at the time. It enabled WordPress to become more than blogging software. But the

TAKING INSPIRATION WordPress was not created in isolation. Although Little and Mullenweg worked on their own, with the expanse of the Atlantic ocean separating them, they did look at other blogging software being created at the time and they took inspiration from it. “There was definitely a lot of studying of rivals and playing catch-up, seeing what other people were doing,” Little says. “For a very long time there was a lot of blogging software and certainly you would see Blogger or Moveable Type with features that were cool and that we thought we might add to WordPress. Eventually it started going the other way round as well and these other apps were copying features that had been added to WordPress.”


‘killer’ feature, Little says, came in the guise of hooks. “It meant you could write additions to the product without having to modify the code, and that was something that only really big grown-up software did, like some of the Java Stacks,” says Little. “This ability to actually change the way it behaves and add things to it without having to touch any of the core files was crucial. It’s still the hardest thing, I think, for new developers to get their heads round how it works, but I think that’s what made it so much easier.” He said it made the process of updating the software so much easier. “Prior to that, with anything like Drupal or any of those tools, whenever there was an update you were in danger of losing your changes because you’d modified original files to call your stuff or to add somebody else’s stuff in. You’d stick these function calls in there. It meant that as soon as you got the new version, if you just literally FTPed the new one over the top of the old one, you were going to lose your stuff and lose your modifications. So I think that was probably one of the key features and I don’t think it’s necessarily something that people appreciate because these days they just never see the problem. They update WordPress or they update the plug-ins and oh, it’s the new version, and nothing’s gone wrong. And yet before then you had to save those files you modified before you updated to the new software.” Mullenweg and Little continued to work on WordPress and the first release came in May of that year.

User-friendliness

Little and Mullenweg saw WordPress as an evolving product. Little worked on doing what he could to eliminate the ability to make mistakes, which he believes was a crucial step forward. “With the original b2, you could lose your settings,” he says. “But with WordPress, I added the config sample PHP and it just took that ability to make a mistake away. I took what was the original b2 settings file and created an Options interface for it. It was another file, you didn’t have to fiddle with it - you didn’t have to know how to edit these files and FTP them back up to your server and stuff like that. I think all those bits helped make it easier, made it harder to cock up and I think that all helped.” The need to be userfriendly was at the forefront of the minds of both developers. It was also important for them that WordPress, like b2, was an open source project. They loved that b2 operated under a General Public License, which meant they had the freedom to take the code, change it and distribute it to other people. They loved that it was free too. “I’ve always been a huge open source advocate,” says Little. “Matt was kind of new to the open source idea, but that was one of the reasons behind him choosing to use b2.” Little attributes the popularity of WordPress to its open source nature (“if it wasn’t open source, if it wasn’t GPL, there wouldn’t be the 20,000 plug-ins that have been written for it or the 10,000 themes,” he says) and it matters not to him that he has not made any direct money from WordPress. “Nobody does,” he says. “It’s

18.9% The percentage of the 10 million websites in the world that run WordPress

“If it wasn’t open source, if it wasn’t GPL, there wouldn’t be the 20,000 plug-ins that have been written for it”


The story of WordPress co-founder, Mark Little

OUTSTAnDinG COnTRiBUTiOn TO DiGiTAL

n The original posting, The Blogging Software Dilemma, on Mat Mullenweg’s website – and Mike Little’s response

not sold and yes, I continued in my day job. Matt went [to work] for CNET, which had just started using WordPress for just a couple of things, and they actually had him doing a standard software development job. But they paid for him to work one day a week on WordPress itself and I think it was through working there that he met a guy called Tony Schneider, who had just sold some software to Yahoo! for £25m or something like. Matt had started Automattic at this point. Schneider later managed to help raise funding for him and joined the service that eventually became WordPress.com. But me, I continued in my day job up until 2008.”

Up until the first release, the development team consisted of just Mullenweg and Little, but five people were working on the project by the end of 2003 and it continued to grow after that. By the end of 2005, Little wasn’t able to stay involved. “I had issues at home, real-life issues which meant that I couldn’t spend the time working on this thing voluntarily,” he says. “It was still a very techy thing, a very geek thing, it wasn’t as good and as user-friendly as it has become today and it certainly wasn’t as prominent.” Cash, he insists, is something that does not motivate him, however. “I need to pay the bills and we need to eat,” he says. “I am the breadwinner of the house and I always have been, but I just wish I could put that side of things in place and do what interests me from that point on. There’s no doubting my passion for open source computing.” Indeed, he has read up on the philosophy behind the General Public License and he has devoured Richard Stallman’s story of how he created the free software movement. “I not only found it very inspiring,” he says, “it just seemed

4 billion

Carrying on

The number of page views of WordPress websites from April 2012 to April 2013

Little considered becoming part of WordPress.com, which is a blog web hosting service provider owned by Automattic, but this was prior to the funding and the company couldn’t afford to pay him a wage. Today it is financially supported via paid upgrades, VIP services and advertising and can pay wages, but in the early days there wasn’t much cash for this and the bulk of the fundraising efforts went on infrastructure.

At SASCon 2013, Mike Little was presented with the inaugural ‘Outstanding Contribution to Digital’ award for his part in co-founding and developing WordPress. The award, which was handed out at a conference at the new Manchester Metropolitan University Business School, acknowledged his instrumental role in setting up and developing the first version of WordPress, which has become the most popular content management system on the internet. Richard Gregory, one of SAScon’s founders, said: “There isn’t a single digital marketing agency that hasn’t made generated income by building WordPress websites, and we are honoured to be able to recognise him with this award.”

the morally right thing to do, for me. The fact is that, at the time, in the 1970s and 1980s, software companies were effectively creating artificial scarcity, based on intellectual ideas that were almost free to reproduce. Back then firms were making floppy disks and putting them in boxes and getting manuals printed and they were charging £500 or £600 for a product that had just £30 or £40 worth of materials. As things moved on, it got easier and easier to distribute software online where the distribution costs and the reproduction costs approach zero, so to then charge artificial amounts on top of that just seemed like the wrong thing to do.” He hopes that future generations go down the same path and release open source software. “But first, he says, “I think it is crucial that we just get kids learning how to code. There are some good moves in that direction and I love what is being done with the Raspberry Pi. Suddenly, a school can’t say it cannot afford to buy lots of computers to experiment with. These are costing £25 each. It’s a great time to be in computing and I feel it’s good to be putting back in and helping people learn.” Mike Little’s new website is at mikelittle.org but he also runs his company site, zed1.com.


Tutorial

MakeextensionsforXBMCwithPython

Rating (only available for hosted plug-ins)

Current media selection

List of installed plug-ins

Configure launcher

Localised description string

Makeextensionsfor XBMCwithPython

Opens changelog for the plug-in

Python is the world’s most popular easy-to-use open source language. Learn how to use it to build your own features for XBMC, the world’s favourite FOSS media centre Advisor

KunalDeois a veteran open source developer. Currently he is leading two open source projects: WinOpen64 and KUN Wiki. He is also a KDE developer. He has contributed to many open source projects, including KDESolaris, Belenix and Openmoko

Resources

XBMC: www.xbmc.org/download Python2.7x PythonIDE(optional) XBMCisperhapsthemostimportantthingthat has ever happened in the open source media centre space. It started its life on the original Xbox videogames console and since then it has become the de facto software for multimedia aficionados. It also has been forked into many other successful media centre applications such as Boxee and Plex. XBMC has ultimately grown into a very powerful open source application with


a solid community behind it. It supports almost all major platforms, including different hardware architectures. It is available for Linux, Windows, Mac OS X, Android, iOS and Raspberry Pi. In these pages we will learn to build extensions for XBMC. Extensions are a way of adding features to XBMC without having to learn the core of XBMC or alter that core in any way. One additional advantage is that XBMC uses Python as its scripting language, and this can be also used to build the extensions. This really helps new developers get involved in the project since Python is easy to learn compared to languages like C/C++ (from which the core of XBMC is made). XBMC supports various types of extensions (or Add-ons): Plugins, Programs and Skins. Plugins add features to XBMC. Depending on the type of feature, a plug-in will appear in the relevant media section of XBMC. For example, a YouTube plug-in would appear in the Videos section. Scripts/Programs are like mini-applications for XBMC. They appear in the Programs section. Skins are important since XBMC is a completely customisable application – you can change

the look and feel of just about every facet of the package. Depending upon which category your extension fits, you will have to create the extension directory accordingly. For example… Plug-ins: plugin.audio.ludaudi: An audio plug-in plugin.video.ludvidi: A video plug-in script.xxx.xxx: A program In this tutorial we will build an XBMC plug-in called LUD Entertainer. This plug-in will provide a nice way to watch videos from Reddit from within XBMC. Our plug-in will show various content such as trailers and documentaries from Reddit. We’ll also allow our users to add their own Subreddit. Each video can then be categorised as Hot, New, Top, Controversial etc. With this plug-in we will demonstrate how easy it is hook into XBMC’s built-in method to achieve a very high-quality user experience. Due to space limitations, we aren’t able to print the full code here. You are highly recommended to explore the cover disc to access the complete code, which has many other amazing functions.

Make extensions for XBMC with Python

Use Python to create a new plug-in for XBMC

TUTORIal

01

Preparingthedirectorystructure

As we have mentioned previously, each XBMC extension type follows a certain directory naming convention. In this case we are building a video plug-in, so the plug-in directory name would be plugin.video.ludlent. But that’s just the root directory name – we will need several other folders and files as well. The following describes the directory structure of LUD Linux Entertainer: plugin.video.ludent – Root Plugin directory |-- addon.xml |-- changelog.txt |-- default.py |-- icon.png |-- LICENSE.txt |-- README `-- resources |-- lib `-- settings.xml

02

Creatingaddon.xml

An addon.xml file needs to be created in the root of the extension directory. The addon.xml file contains the primary metadata from a XBMC extension. It contains overview, credits, version information and dependencies information about the extension. The root element of addon.xml is the element. It is defined as:

rest of the content is placed here Here, id is the identifier for the plug-in, so it should be unique among all the XBMC extensions, and id is also used for the directory name; version tells XBMC the extension version number, which helps in its ability to deliver automatic updates – XBMC follows the Major.Minor.Patch versioning convention; name is the English title of the plug-in. Note: Steps 3 to 5 cover entries that need to be added within the addon.xml file.

03

addingdependencyinformation

Dependency inside an extension is managed using the element.

version="2.1.0"/> In the above code we have added a dependency to a library called xbmc.python version 2.1. Currently it is added as a mandatory dependency. To make the dependency optional you will need to add optional="true"; eg
version="0.1.0" optional="true" /> In the above example we have added core dependency xbmc.python to 2.1.0 because it’s the version shipped with XBMC version Frodo 12.0 and 12.1 . If you were to add xbmc.python to 2.0 then it would only work in XBMC Eden 11.0 and not in the latest version. For the current version of XBMC 12.1, the following versions of core XBMC components are shipped: xbmc.python 2.1.0 xbmc.gui 4.0.0 xbmc.json 6.0.0 xbmc.metadata 2.1.0 xbmc.addon 12.0.0 In addition to xbmc.python we are also adding some third-party plug-ins as dependencies, such as plugin.video.youtube. These plug-ins will be installed automatically when we install plugin.video.ludent.

04

Settinguptheproviderand entrypoint

Our extension is supposed to provide the video content for XBMC. In order to convey that, we have to set up the following element:

video Here, the library attribute sets up the plug-in entry point. In this example default.py will be executed when the user activates the plug-in. The elements sets up the media type it provides. This also gets reflected in the placement of the plug-in. Since ours is a video plug-in, it will show up in the Videos section of XBMC.

05

Settingupplug-inmetadata

Metadata about the plug-in is provided in . The following are the important elements… : Most of the time, XBMC extensions are cross-platform compatible. However, if you depend on the native platform library that is only available on certain platforms then you will need to set the supported platforms here. Accepted values for the platform are: all, linux, osx, osx32, osx64, ios (Apple iOS) , windx (Windows DirectX), wingl (Windows OpenGL) and android.
: This gives a brief description of the plug-in. Our example sets the language attribute as English, but you can use other languages too. : A detailed description of the plug-in. : Webpage where the plug-in is hosted. : Source code repository URL. If you are hosting your plug-in on GitHub, you can mention the repository URL here. : Discussion forum URL for your plug-in. : Author email. You can directly type email or use a bot-friendly email address like max at domain dot com.

06

Settingchangelog,icon,fanart andlicence

We need a few additional files in the plug-in directory… changelog.txt: You should list the changes made to your plug-in between releases. The changelog is visible from the XBMC UI. An example changelog: 0.0.1 - Initial Release 0.0.2 - Fixed Video Buffering Issue icon.png: This will represent the plug-in in the XBMC UI. It needs to be a non-transparent PNG file of size 256x256. fanart.jpg (optional): The fanart.jpg is rendered in the background if a user selects the plug-in in XBMC. The art needs to be rendered in HDTV formats, so its size can range from 1280x720 (720p) up to the maximum 1920x1080 (1080p).


Tutorial


License.txt: This file contains the licence of the distributed plug-in. The XBMC project recommends the use of the Creative Commons Attribution-ShareAlike 3.0 licence for skins, and GPL 2.0 for add-ons. However, most of the copyleft licences can be used. Note: For the purpose of packaging, extensions/ add-ons/themes/plug-ins are the same.

07

Providingsettingsfortheplug-in

Settings can be provided by the file resources/settings.xml. These are great for userconfigurable options. Partial:resources/settings.xml

Here, label defines the language id string which will then be used to display the label. id defines the name which will be used for programmatic access. type defines the data type you want to collect; it also affects the UI which will be displayed for the element. default defines the default value for the setting. You should always use a default value wherever possible to provide a better user experience.


The following are a few important settings types that you can use… text: Used for basic string inputs. ipaddress: Used to collect internet addresses. number: Allows you enter a number. XBMC will also provide an on-screen numeric keyboard for the input. slider: This provides an elegant way to collect integer, float and percentage values. You can get the slider setting in the following format:

In the above example we are creating a slider with min range 1, max range 10 and step as 1. In the option field we are stating the data type we are interested in – we can also set option to "float" or "percent". bool: Provides bool selection in the form of on or off. file: Provides a way to input file paths. XBMC will provide a file browser to make the selection of file. If you are looking to make selection for a specific type of file you can use audio, video, image or executable instead of file. folder: Provides a way to browse for a folder… Example:

Here, source sets the start location for the folder, while option sets the write parameter for the application. sep & lsep: sep is used to draw a horizontal line in the setting dialog; lsep is used for drawing a horizontal line with text. They do not collect any input but are there for building better user interface elements…

08

Languagesupport

Language support is provided in the form of the strings.xml file located in resources/languages/[language name]. This approach is very similar to many large software projects, including Android, where static strings are never used.

resource/language/english/string.xml example:

Add subreddit Hot New Top Controversial Hour Day Week Month Year As you may have seen in the settings.xml example, all the labels are referring to string ids. You can have many other languages as well. Depending upon the language XBMC is running in, the correct language file will be loaded automatically. Post XBMC Frodo (12.1), strings.xml will be deprecated. Post Frodo, XBMC will be moved to a GNU gettext-based translation system; gettext uses PO files. You can use a tool called xbmc-xml2po to convert strings.xml into equivalent PO files.

09

Buildingdefault.py

Since our plug-in is small, it will all be contained inside default.py. If you are developing a more complex add-on then you can create supporting files in the same directory. If your library depends upon third-party libraries, you have two ways to go about it. You can either place the third-party libraries into the resources/lib folder; or bundle the library itself into a plug-in, then add that plug-in as the dependency in the addon.xml file. Our plug-in works with reddit.tv. This is the website from Reddit which contains trending videos shared by its readers. Videos posted on Reddit are actually sourced from YouTube, Vimeo and Dailymotion. We will be starting default.py with the following imports:

import urllib import urllib2 … import xbmcplugin



TUTORIal

import xbmcgui import xbmcaddon Apart from xbmcplugin, xbmcgui and xbmcaddon, the rest are all standard Python libraries which are available on PyPI (Python Package Index) via pip. You will not need to install any library yourself since the Python runtime for XBMC has all the components built in. urllib and urllib2 help in HTTP communication. socket is used for network I/O; re is used for regular expression matching; sqlite3 is the Python module for accessing an SQLite embedded database; xbmcplugin, xbmcgui and xbmcaddon contain the XBMC-specific routine.

10

Initialising

During the initialisation process, we will be reading various settings from settings.xml. Settings can be read in the following way:

addon = xbmcaddon.Addon() filterRating = int(addon. getSetting("filterRating")) filterVoteThreshold = int(addon.getS etting("filterVoteThreshold")) In order to read settings of type bool you will need to do something like:

filter = addon.getSetting("filter") == "true" We are also setting the main URL, plug-in handle and the user agent for it:

pluginhandle = int(sys.argv[1]) urlMain = "http://www.reddit.com" userAgent = "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:22.0) Gecko/20100101 Firefox/22.0" opener = urllib2.build_opener() opener.addheaders = [(‘User-Agent’, userAgent)]

11

Readinglocalisedstrings

As mentioned, XBMC uses strings.xml to serve up the text. In order to read those strings, you will need to use getLocalizedString.

translation = addon. getLocalizedString translation(30002) In this example, translation(30002) will return the string "Hot" when running in an English environment.

idFile

idPath

strFilename

playCount

lastPlayed

1

1

plugin://plugin.

2

2

plugin://plugin.

1

2013-08-07 22:42

3

2

plugin://plugin.

1

2013-08-08 00:09

4

2

plugin://plugin.

1

2013-08-08 00:55

5

2

plugin://plugin.

1

2013-08-08 00:58

dateadded

2013-08-06 23:47

12

Buildinghelperfunctions

In this step we will look at some of the important helper functions. getDbPath(): This returns the location of the SQLite database file for videos. XBMC stores library and playback information in SQLite DB files. There are separate databases for videos and music, located inside the .xbmc/userdata/ Database folder. We are concerned with the videos DB. It is prefixed with ‘MyVideos’…

def getDbPath(): path = xbmc. translatePath("special://userdata/ Database") files = os.listdir(path) latest = "" for file in files: if file[:8] == ‘MyVideos’ and file[-3:] == ‘.db’: if file > latest: latest = file return os.path.join(path, latest) getPlayCount(url): Once we have the database location, we can get the play count using a simple SQL query. The MyVideo database contains a table called files, which keeps a record of all the video files played in XBMC by filename. In this case it will be URL.

dbPath = getDbPath() conn = sqlite3.connect(dbPath) c = conn.cursor() def getPlayCount(url): c.execute(‘SELECT playCount FROM files WHERE strFilename=?’, [url]) result = c.fetchone() if result: result = result[0] if result: return int(result) return 0 return -1

The above table is an example of a files table. addSubreddit(): Our plug-in allows users to add their own Subreddit. This function takes the Subreddit input from the user, then saves it in the subreddits file inside the addon data folder. The following sets the subreddits file location:

subredditsFile = xbmc. translatePath("special://profile/ addon_data/"+addonID+"/subreddits") this translates into .xbmc/userdata/ addon_data/plugin.video.ludent/ subreddits def addSubreddit(): keyboard = xbmc.Keyboard(‘’, translation(30001)) keyboard.doModal() if keyboard.isConfirmed() and keyboard.getText(): subreddit = keyboard. getText() fh = open(subredditsFile, ‘a’) fh.write(subreddit+’\n’) fh.close() This function also demonstrates how to take a text input from the user. Here we are calling the Keyboard function with a text title. Once it detects the keyboard, it writes the input in the subreddits file with a newline character. getYoutubeUrl(id): When we locate a YouTube URL to play, we pass it on to the YouTube plug-in (plugin.video.youtube) to handle the playback. To do so, we need to call it in a certain format…

def getYoutubeUrl(id): url = "plugin://plugin. video.youtube/?path=/root/ video&action=play_video&videoid=" + id return url


Tutorial


On the same lines, we can build a function to place links as well… Similarly for Vimeo:

def getVimeoUrl(id): url = "plugin://plugin.video. vimeo/?path=/root/video&action=play_ video&videoid=" + id return url And for Dailymotion:

def getDailyMotionUrl(id): url = "plugin://plugin.video. dailymotion_com/?url=" + id + "&mode=playVideo" return url Once we have the video URL resolved into the respective plug-in, playing it is very simple:

def playVideo(url): listitem = xbmcgui. ListItem(path=url) xbmcplugin. setResolvedUrl(pluginhandle, True, listitem)

13

Populatingplug-incontentlisting

xbmcplugin contains various routines for handling the content listing inside the plug-ins UI. The first step is to create directory entries which can be selected from the XBMC UI. For this we will use a function called xbmcplugin.addDirectoryItem. For our convenience we will be abstracting addDirectoryItem to suit it to our purpose, so that we can set name, URL, mode, icon image and type easily.

def addDir(name, url, mode, iconimage, type=""): u = sys.argv[0]+"?url="+urllib. quote_plus(url)+"&mode="+str(mode)+" &type="+str(type) ok = True liz = xbmcgui.ListItem(name, iconImage="DefaultFolder.png", thumbnailImage=iconimage) liz.setInfo(type="Video", infoLabels={"Title": name}) ok = xbmcplugin. addDirectoryItem(handle=int(sys. argv[1]), url=u, listitem=liz, isFolder=True) return ok


def addLink(name, url, mode, iconimage, description, date): u = sys.argv[0]+"?url="+urllib. quote_plus(url)+"&mode="+str(mode) ok = True liz = xbmcgui.ListItem(name, iconImage="DefaultVideo.png", thumbnailImage=iconimage) liz.setInfo(type="Video", infoLabels={"Title": name, "Plot": description, "Aired": date}) liz.setProperty(‘IsPlayable’, ‘true’) ok = xbmcplugin. addDirectoryItem(handle=int(sys. argv[1]), url=u, listitem=liz) return ok Based on the abstractions we have just created, we can create the base functions which will populate the content. But before we do that, let’s first understand how Reddit works. Most of the Reddit content filters are provided through something called Subreddits. This allows you to view discussions related to a particular topic. In our plug-in we are interested in showing videos; we also want to show trailers, documentaries etc. We access these using Subreddits. For example, for trailers it would be reddit.com/r/ trailers. For domains we can use /domain; for example, to get all the YouTube videos posted on Reddit, we will call reddit.com/domain/ youtube.com. Now you may ask what is the guarantee that this Subreddit will only list videos? The answer is that it may not. For that reason we scrape the site ourselves to find videos. More on this in the next step. The first base function we’ll define is index(). This is called when the user starts the plug-in.

def index(): defaultEntries = ["videos", "trailers", "documentaries", "music"] entries = defaultEntries[:] if os.path. exists(subredditsFile): fh = open(subredditsFile, ‘r’) content = fh.read() fh.close() spl = content.split(‘\n’) for i in range(0, len(spl), 1):

if spl[i]: subreddit = spl[i] entries. append(subreddit) entries.sort() for entry in entries: if entry in defaultEntries: addDir(entry.title(), "r/"+entry, ‘listSorting’, "") else: addDirR(entry.title(), "r/"+entry, ‘listSorting’, "") addDir("[ Vimeo.com ]", "domain/vimeo.com", ‘listSorting’, "") addDir("[ Youtu.be ]", "domain/ youtu.be", ‘listSorting’, "") addDir("[ Youtube.com ]", "domain/youtube.com", ‘listSorting’, "") addDir("[ Dailymotion.com ]", "domain/dailymotion.com", ‘listSorting’, "") addDir("[B]"+translation(30001)+" -[/B]", "", ‘addSubreddit’, "") xbmcplugin. endOfDirectory(pluginhandle) Here, the penultimate entry makes a call to addSubreddit. listSorting takes care of sorting out the data based on criteria such as Hot, New etc. It also calls in Reddit’s JSON function, which returns nice easy-to-parse JSON data. We have created a settings entry for all the sorting criteria. Based on what is set, we go ahead and build out the sorted list.

def listSorting(subreddit): if cat_hot: addDir(translation(30002), urlMain+"/"+subreddit+"/hot/. json?limit=100", ‘listVideos’, "") if cat_new: addDir(translation(30003), urlMain+"/"+subreddit+"/new/. json?limit=100", ‘listVideos’, "") if cat_top_d: addDir(translation(30004)+": "+translation(30007), urlMain+"/"+subreddit+"/ top/.json?limit=100&t=day", ‘listVideos’, "") xbmcplugin. endOfDirectory(pluginhandle)



TUTORIal

def listVideos(url): currentUrl = url xbmcplugin.setContent(pluginhandle, "episodes") content = opener.open(url).read() spl = content.split(‘"content"’) for i in range(1, len(spl), 1): entry = spl[i] try: match = re.compile(‘"title": "(.+?)"’, re.DOTALL).findall(entry) title = match[0].replace("&", "&") match = re.compile(‘"description": "(.+?)"’, re.DOTALL). findall(entry) description = match[0] match = re.compile(‘"created_utc": (.+?),’, re.DOTALL).findall(entry) downs = int(match[0].replace("}", "")) rating = int(ups*100/(ups+downs)) if filter and (ups+downs) > filterVoteThreshold and rating < filterRating: continue title = title+" ("+str(rating)+"%)" match = re.compile(‘"num_comments": (.+?),’, re.DOTALL). findall(entry) comments = match[0] description = dateTime+" | "+str(ups+downs)+" votes: "+str(rating)+"% Up | "+comments+" comments\n"+description match = re.compile(‘"thumbnail_url": "(.+?)"’, re.DOTALL). findall(entry) thumb = match[0] matchYoutube = re.compile(‘"url": "http://www.youtube.com/ watch\\?v=(.+?)"’, re.DOTALL).findall(entry) matchVimeo = re.compile(‘"url": "http://vimeo.com/(.+?)"’, re.DOTALL).findall(entry) url = "" if matchYoutube: url = getYoutubeUrl(matchYoutube[0]) elif matchVimeo: url = getVimeoUrl(matchVimeo[0].replace("#", "")) if url: addLink(title, url, ‘playVideo’, thumb, description, date) except: pass match = re.compile(‘"after": "(.+?)"’, re.DOTALL).findall(entry) xbmcplugin.endOfDirectory(pluginhandle) if forceViewMode: xbmc.executebuiltin(‘Container.SetViewMode(‘+viewMode+’)’)

14

Populatingtheepisodeview(listingvideos)

At this point we have the URL in hand, which returns JSON data; now we need to extract the data out of it which will make sense to us. By looking at the JSON data, you can see there’s a lot of interesting information present here. For example, url is set to youtube.com/watch?v=n4rTztvVx8E; title is set to ‘The Counselor – Official Trailer’. There also many other bits of data that we will use, such as ups, downs, num_comments, thumbnail_url and so on. In order to filter out the data that we need, we will use regular expressions. There is one more thing to note: since we are not presenting directories any more but are ready to place content, we have to set the xbmcplugin.setContent to episodes mode.

In the code listed to the left here, we are opening the URL, then – based on regular expression matches – we are discovering the location title, description, date, ups, downs and rating. We are also locating video thumbnails and then passing them on to XBMC. Later in the code, we also try to match the URL to a video provider. With our plug-in we are supporting YouTube, Vimeo and Dailymotion. If this is detected successfully, we call the helper functions to locate the XBMC plugin based playback URL. During this whole parsing process, if any exception is raised, the whole loop is ignored and the next JSON item is parsed.

15

Installing&runningtheadd-on

You can install the add-on using one of the following two methods: • You can copy the plug-in directory to .xbmc/addons. • You can install the plug-in from the zip file. To do so, compress the add-on folder into a zip file using the command:

$ zip -r plugin.video.ludent.zip plugin.video.ludent To install the plug-in from the zip file, open XBMC, go to System then Add-ons, then click ‘Install from zip file’. The benefit of installing from a zip file is that XBMC will automatically try to install all the dependent plug-ins as well. Once you have the plug-in installed, you can run it by going to the Videos Add-ons section of XBMC, selecting Get More… and then clicking on LUD Reddit Viewer. You can access the settings dialog of the plug-in by right-clicking the LUD Reddit Viewer, then selecting ‘Add-on settings’. So, you have seen how robust and powerful XBMC’s extension system is. In this example, we were able to leverage the full power of Python (including those magical regular expression matches) from within XBMC. XBMC itself also offers a robust UI framework, which provides a very professional look for our add-on. As powerful as it may seem, we have only built a video plug-in. XBMC’s extension system also provides a framework for building fully fledged programs (called Programs). We will cover this in a later issue.


Tutorial

Master Vim in easy steps

All the examples presented in this article are tested for Vim version 7.3.547 on Ubuntu 13.04

Just type :help and Vim displays some valuable info for newbies, such as navigation keys and keyboard shortcuts to enable the mouse in xterm or GUI etc

Type :help iccf and Vim displays information (including weblinks) related to donations for the needy in Uganda as well as for the development of the Vim editor

Master Vim in easy steps Take a step ahead, learn some advanced features and get more productive with the Vim editor Advisor

Himanshu Arora is a

software programmer, open source enthusiast and Linux researcher. His articles have been featured on IBM developerWorks, Computerworld and in Linux Journal. He (along with some other Linux freaks) blogs at mylinuxbook.com

Resources

Vim: www.vim.org/download.php


Thanks to a steep learning curve, many people either avoid using Vim or use it on a very basic level. If you’re guilty of either of these then you’re really missing out. Vim, first released in November 1991, is a command-line-based text editor that was developed by Bram Moolenaar as an improved Vi clone for Amiga platform. Besides including all the features of the popular Vi editor, it also contains a lot of new features and so derives its name – from ‘Vi improved’. As well as being a text editor, Vim can be used as an integrated development environment by software programmers. Vim provides a wide range of features, but as it is a command-line utility it has a steep learning curve. Please note that Vim is not a word processor, which means that you cannot do layout-related changes with it. While you will get to know about the real strengths of the Vim editor once you master it,

on the whole some of the prominent pros include fast text editing (because of little to almost no use of the mouse) and easy execution from anywhere on the command line. There are also many GUI front-ends (like gVim) available for Vim. Although it is command-line based, Vim has a loyal following and is extensively used by system administrators and software programmers. Though it is hard to learn and understand all the features that Vim provides, in order to reap its real benefits it is essential to master Vim for your dayto-day work. Through this article you will learn how to work with multiple files, how to indent and fold code, how to search and replace keywords, how to split the Vim window horizontally/vertically, and many other related features provided by Vim. Note: This article assumes that you have some basic knowledge (opening, editing, saving and closing a file) of the Vim editor.


Learn some advanced features of Vim

TUTORIal

01

Work with multiple files

While most regular users use Vim to edit one file at a time, it can also be used to edit multiple files in parallel. To open multiple files with the Vim editor, just provide names of all these files as arguments to the vim command. The first file is displayed by default. Type :n to switch to the next file, :prev (or :N) to switch to previous file, :bf to switch to first file, :bl to switch to last file and :bw to close the file.

02

Work with multiple files

Sometimes it is required to open a new or an existing file while editing an already opened set of files. Well, this can be done by typing :e followed by the filename (along with a complete path if it’s not located in the current working directory).

03

Get list of currently opened files in Vim

04

Use wildcard characters

To get the list of files currently opened in the Vim editor, just type :ls. This will display list of opened files along with other information like the current line number of the cursor in a file, file in current active window (represented by %a), file in previous active window (represented by #) etc. Switch between current and previous active windows by typing :b#.

Vim also supports wildcard characters (like *, ? etc) while opening multiple files at a time. This is especially useful in cases where multiple log files begin with a common set of characters like the current date (2013-08-05---.log), or where multiple programming source files have same language extension such as .c or .cpp.

05

Copy-paste across the files

Another frequent requirement is to copy from one file and paste into another. For this, you need to split the Vim window to open both files. This can be done either by using the -o option with the vim command (vim -o ); or by opening a file with vim , then opening the second file in split window mode from within the active Vim window with :split . To switch cursor control between the two windows, press Ctrl+w (a couple of times). Copy-paste operation across the files can be done as follows: open files in split mode (as explained above); copy the required text from one file; press Ctrl+w to switch the control to the other file; then paste the copied text. You can also split a Vim window vertically. All you need to type is :vsp from within an active window.


Tutorial


06

Close all files

07

Close files without closing Vim

To close all the opened files in one go, add ‘a’ to regular close options like :q, :wq or :q!. So, to close all the files in a single shot, do something like :qa or :wqa or :qa!. Normally, when the last open file is closed, the Vim application also exits. But, if it is required to close the last open file without closing the application, then just type :bd. This closes the current file and opens an empty buffer.

While most regular users use Vim to edit one file at a time, it can also be used to edit multiple files in parallel

08

Fold blocks of code

Another frequent requirement – which software programmers usually have – is to fold some blocks of code in order to save window space. This helps them to focus on the required code blocks. Vim does support block folds. For this, the first step is to bring cursor inside the


braces of the function definition. For example, bring the cursor to the first line of the function body. Once there, just type va}zf. As you type this, you will observe that va is used to activate visual mode in Vim, while } selects the complete block including curly braces and zf enables the fold. To open the fold, press zo; to close it, press zc. Make sure that the cursor is within the block while performing fold open and close. Typing va}zf creates a fold (that is invisible). zo and zc work only when a fold is created. An existing fold can be deleted by typing zd.

09

Manual indenting

Another important feature that Vim provides is code indentation. Software programmers are required to indent their code and Vim provides easy steps for code indentation. To indent a single line of code, you can use >> or << to indent the line to the right or left respectively. Multiple lines can also be indented using [number-of-lines]>> or


Learn some advanced features of Vim

TUTORIal

For those programmers who want everything automated, Vim also provides an auto-indenting feature

[number-of-lines]<<; for example, 10>> or 10<<. This is a better technique than indenting each line, but you still need to count the number of lines to indent. This could prove frustrating, especially if the number of lines is very large. Fortunately, there is another trick: to select the lines by working with Vim in visual mode. In order to do this, you first need to bring Vim into visual mode. This (as mentioned previously) can be done using va. Once in visual mode, use the arrow keys to select all the lines that you want to indent in one go. After this, all you need to do is press > or < and the whole selected area will be indented accordingly.

10

automatic indentation

For those programmers who want everything automated, Vim also provides an auto-indenting feature. For example, to enable auto-indenting for C code, use :set autoindent and :set cindent. Now, try writing some C code and you will see that Vim automatically produces indentation as you write it. Sometimes, depending upon the existing settings of your Vim editor, lines might get indented to a number of spaces other than four spaces or any other default value that you desire. As a solution to this, you can set the number of spaces to indent using

:set shiftwidth=. For example, use :set shiftwidth=4 to indent lines by four spaces.

11

Search words

12

Replace words

To search for a word in the active window, simply type /[search keyword]. This will enable Vim’s search mode and find the first occurrence of the searched keyword. Use n (just press n) in order to search more occurrences of the keyword. Note that you cannot do a backward search here. If you need to do a backward search then just type :?[search keyword]. This will enable Vim’s backward search mode. Again, use n to continue the search, but backwards this time. Sometimes the keyword is present in the text/source file and it is desired to find other occurrences of that word in the current text/ source file. In this case, just put the cursor below that word and press * (ie Shift+8). This way, you can search for a word without even typing it. Vim also supports search and replace operations. To execute a basic replace operation, just type :%s/[keywordto-search]/[keyword-to-replace-with] to replace keyword-to-search with keyword-toreplace-with. This trick is good if you want to replace all the occurrences of a searched keyword, but what if it is desired to replace only selected occurrences? Well, there is a way through which you can run a search and replace operation in interactive mode. This means that Vim will confirm before replacing the keyword each time. This can be done through :%s/[keyword-to-search]/[keyword-toreplace-with]/c. The first occurrence is always highlighted and Vim displays a prompt (in green, at the bottom) where you can input your choice of whether you want to replace this occurrence or not. Here, y = Yes, replace this occurrence; n = No, skip this occurrence; a = Replace this and all other occurrences; q = Quit the command; l = Replace this match and then quit the command. Use Ctrl+e (^E) and Ctrl+y (^Y) to scroll the window up and down in this mode. Also, use i and I (along with /c, for example /ci or /cI) for case-insensitive and case-sensitive search.


Tutorial

Make a Python Twitter client

Create your own app details by using the Twitter Developer account tools, either for personal use or for an app you intend to release

Access the entire dataset of Twitter via the Python wrapper, allowing you to grab timelines, lists and user profiles among others

Create your authentication keys for your user and OAuth, letting you tap into the Twitter API


Write your own tweets in Python using the Twython module to access components from the Twitter API

Learn the basics of the Twitter API using Python libraries and create a simple Twitter client to make and monitor tweets Advisor

Rob Zwetsloot models complex systems and is a web developer proficient in Python, Django and PHP. He loves to experiment with computing

Resources

A Twitter account Python 2: www.python.org/


Python has many strengths, and one of them is the way you can use it to create lightweight desktop software and packages for the Internet of Things. One of the services used for this is Twitter, which has a few Python APIs you can make use of in a Python script to check and post the tweets from a specified user. With this you can create a standard Twitter client in the command line, or make a UI for it

with Tkinter (from previous issues of LUD). You can also specify the login details you’d normally ask for from a client and then use it to check for specific words on Twitter, retweets, messages received, or if a specific person is sending tweets. For this tutorial we’ll be using Twython, which provides a pure Twitter interface for Python, and show you how to get your own unique API key to use it with Twitter itself.


Create a simple Twitter client to make and monitor tweets

TUTORIal

01

We need to create a Python file to hold all our authentication details. Start by importing Twython

accountability

To create a Twitter app, you need a Twitter account. Sign into your account, or create a separate one if you want to split up personal and development accounts on the service. Once that’s done, go to dev.twitter.com and log in using your desired account.

02

New beginnings

Go to ‘My applications’ and click ‘Create a new application’. Here you’ll need to enter the app’s name, a short description and a website where more details about yourself and/or the app can be found. Names of apps are not allowed to use the word Twitter in them.

04

access token

05

Install Pip

We can now create an access token for the application to work with your Twitter account. Go back to the details once the read and write permissions have been changed, and scroll down to the bottom. Click ‘Create my access token’ to retrieve it. We’ll install the latest version of pythontwitter from its website. To do this, first install pip on your system, available in repos as python-pip. As we’re using Debian, this looks like:

07

authentication file

We need to create a Python file to hold all our authentication details. Start up IDLE, or a text editor of your choice, and start by importing Twython with:

from twython import Twython Make sure you have the keys we created earlier handy to add in the next parts. If the output is long, type ‘it’ to go to the next screen.

$ sudo apt-get install python-pip …which allows us to set up Python modules.

03

Privileges

After this has been created, you’ll be brought to the details page of the app. Before we go any further, click on Settings and select Read, Write and Access Direct Messages under Application Type so that we can use it properly as a Twitter client.

06

08 Install Twython

Now that we have Pip installed, we can go ahead and install Twython. To do this, continue in your terminal and put:

$ sudo pip install twython

app keys Add the following to your code:

APP_KEY = 'YOUR_CONSUMER_KEY' APP_SECET = 'YOUR_CONSUMER_SECRET' …replacing YOUR_APP_KEY and YOUR_APP_ SECRET with your own consumer key and consumer secret respectively.

This will get the Twython module, and all the OAuth packages you need to log into your account with tokens we created.


Tutorial

09


Access keys

Now we add the access tokens that we created to the script with:

OAUTH_TOKEN = 'YOUR_ACCESS_TOKEN' OAUTH_TOKEN_SECRET = 'YOUR_ACCESS_ SECRET' …where again you’ll need to replace YOUR_ ACCESS_TOKEN and YOUR_ACCESS_SECRET with the relevant numbers.

10

Verification

Now’s a good time to verify if what you’ve done so far actually works. Enter the following at the bottom of the script:

twitter = Twython(APP_KEY, APP_SECRET, OAUTH_TOKEN, OAUTH_TOKEN_SECRET) twitter.verify_credentials()

twitter.get_user_timeline(screen_name = 'username')

And run. If it doesn’t come up with any errors, it’s all working fine.

15

Full timeline

We can access the account’s full timeline by using the get_home_timeline variable like so:

twitter.get_home_timeline()

11

If you printed this out, it would display all the unfiltered data from the last 20 tweets on your timeline. You can modify the amount of tweets by adding the count parameter to the get_home_timeline. We’ll set it to five for now:

Test post

As it all seems to be working, you could try making a test post straight to Twitter. At the bottom of our code, enter:

twitter.update_status(status='Test') And then run it again. If it’s successful, there will be no errors and it will show up on your timeline.

13

Update

To post this, we use the update_status bit from before, only it now uses the string from post to update our timeline. Add:

twitter.get_home_timeline(count = 5) We’ll need to parse the data to make sure we get something coherent and recognisable as a timeline.

twitter.update_status(status=post) And then save the file. Run it, and test the code again.

12

Write a post

Let’s create a simple way to post tweets to your timeline via our script. We’ll use human input like so:

post = raw_input("Write your tweet: ") …which will store our tweet as a string in post.


14

Timeline

To access the timeline of our account tweets, we use the following:

twitter.get_user_timeline() This accesses the past 20 posts our account has made. You can specify which timeline to check as well by adding the screen_name option:

Create a simple way to post tweets to your timeline


Create a simple Twitter client to make and monitor tweets

TUTORIal

16

19 Search tweets

We can search Twitter for specific keywords using the following:

twitter.search(q='linux') This will return a mixed result of tweets relating to the word Linux. You can filter them with the result_type parameter, by setting it as mixed, recent or popular.

Favouriting

This works very similar to retweets, using the unique ID for the tweet used in the URL to determine which tweet to favourite. The function for this is create_favorite, and is written as:

twitter.create_favorite(id = '12345') Make sure to use the American spelling (favorite) when doing this.

22

Trending topics

Everyone knows what everyone else is talking about thanks to Twitter’s trending topics, whether it’s a young Canadian musician or important world events. You access the trends with:

twitter.get_place_trends(id = '1') An ID of 1 returns global trends. You can specify different IDs for different locales.

20 17

Retrieve favourites

All of a user’s favourites are stored by Twitter so that you can recover them at any time. You can either get your own, or specify a user to get the favourites from. The basic code is:

Follow

To follow someone on Twitter, we use the create_friendships function. We need either the screen name or numerical ID of the Twitter user you want to follow – you’ll most likely be using the screen name, so we’ll write it like so:

twitter.get_favorites() …which will get your own favourites. As before, you can specify the user ID number or screen name with user_id and screen_name respectively to get a specific list.

18

As retweets are an integral part of Twitter, the function for this is simply retweet. We require the tweet ID for this, the numerical string used for each tweet and displayed in the URL for a tweet. We use it with:

twitter.retweet(id = '12345')

Retrieve list

If you prefer to use Twitter by curating lists of people, you can get the contents of any list using the get_list_statuses function:

twitter.get_list_statuses(id '12345')

twitter.create_friendship(screen_name = 'LinuxUserMag')

Retweeting

23

=

Each list has a unique ID, or a slug, that you can use. You can also call members of any list, or anyone that subscribes to it.

21

Mentions

You can also access the list of mentions for your authenticated account. To do this, use the get_mentions_timeline function. This works like the other timelines, allowing you limit the amount of posts you get from the selection. Limit it to five like before with:

24

The end

With all these functions, you can start picking and choosing data and making our code do a lot more than just post tweets. Getting specific attributes from the timeline functions will allow you to display a coherent timeline, and it also includes the details needed to follow the links to the users and their links.

twitter.get_mentions_ timeline(count='5')


Review index

Essential kit, software and resources for the open source scene

REVIEWS

“An easy way to get started with wireless microcontroller development” Wireless Inventors Kit

Group Test 72 IDE super-test

Enhance your workflow with the best dev environments…

Hardware 12 MinnowBoard

Has the Raspberry Pi really met its match?

79 Nook HD+

The perfect mix of low cost and high performance?

Software Code::Blocks

Geany

82 Sparky Linux 3.0

Books 85

Eclipse

Netbeans

One of the first distros to use Debian 7.0 ‘Jessie’

How we review

Our experts thoroughly test the kit and grade it using the following criteria Avoid at all costs

A designer/developer’s bad day Good but could do better Get this. It won’t disappoint

The latest Linux reads dissected

Software or hardware nirvana


Review

Integrated development environment group test

GROUP TEST

Integrated development environments

We pit four of the best IDEs against each other to find out which is the best way to streamline and enhance your workflow The humble IDE can be a very powerful tool for any coder – whether it’s for hobby programming or used professionally. With all the various programming languages one can use, there’s an even greater number of IDEs that can help you write code in them – each with their own advantages and disadvantages.


In this test, we’ll be looking at the more fully featured, multi-language IDEs, rather than specialised single-language environments or lightweight equivalents. We’re also testing these IDEs for their abilities to be expanded through plug-ins and add-ons – either for other languages, or different interface effects.

We’ve chosen Eclipse, Code::Blocks, Geany and Netbeans for this review. While they’re not included, KDevelop and Anjuta are other, desktop-environment-specific IDEs that are also great. We’ve chosen platform-independent IDEs for this test, although those two will generally work fine on other desktops.


Four of the best IDEs go head to head

REVIEW

Code::Blocks

A relatively new IDE, Code::Blocks was first released in early 2008 after three years of release candidates. Although a C++ IDE by default, it has plug-in support to extend its functionality to allow for building and testing of other languages. However, for pure coding, Code::Blocks can be used to write scripts in various languages thanks to support for syntax of a variety of different languages. However, you cannot test these without add-ons. Unfortunately, the plug-in scene for Code::Blocks is fairly immature and there isn’t even proper support for Python and other interpreted programming languages. Plug-ins are found via the Code::Blocks wiki and are not particularly well laid out at the moment. Plug-ins are installed manually, which would be fine normally, but the other IDEs in the test have some interesting ways of managing plug-ins that make this method seem somewhat archaic. While you won’t be able to properly debug test code, the interface for Code::Blocks is still very nice for actually writing your code. Projects are handled via proprietary projects files which link to specific folders. Projects don’t need to be created with a specific language in mind and, like some text editors, it will smartly know to highlight the syntax for different languages. Browsing

A more open IDE originally for C++, but now able to do a bit more

■ There are a few first-party plug-ins available, but not many third-party

doesn’t always work for all functions and classes; however, it will allow you to perform simple code editing to test elsewhere if you specifically like the interface. Code::Blocks is also quite customisable, allowing you to change the look and behaviour of the editor, the way the compiler works and even editing the startup script for the application itself.

“Unfortunately, the plug-in scene for Code::Blocks is fairly immature”

■ The interface is nice and aids workflow

Code::Blocks is a nice piece of software, although due its immaturity it doesn’t quite have the best plug-in support of the other IDEs in this test – especially if you want to use it for multilanguage programming. It’s a bit lighter than Eclipse at least, and the interface is well laid out, but it may still be a few years before it becomes preferable to the others.

SCORES

Installation

Available in repos, but binaries and source code is easily accessible elsewhere

8

Workflow

Code::Blocks’ interface is generally good for workflow, although it doesn’t support all languages properly

7

Features

A great selection of features that can all be heavily customised

7

Plug-in support

Very limited right now, meaning that not all languages are properly supported

4

Overall

Code::Blocks has a great interface, and some great ideas on how to code and manage projects, but the plug-in selection needs to be improved

6


Review


Geany

A fully featured IDE that’s a little more lightweight than most Geany is sometimes mistaken for a glorified text editor. In reality, it’s a full IDE, albeit slightly more lightweight than most. Geany has multi-language support out of the box, with easy options to create files that use different languages as part of the main interface. Projects are kept in specific folders, like Eclipse, although there is a file to go with them that Geany can read to manage the projects. Multiple projects can be viewed and edited at a time, all in different languages. There are also debuggers and builders for the various languages that support them, and you can run and test stuff like Python that doesn’t need compiling as such. The rest of the interface for Geany is clean and well labelled. Code is automatically highlighted with the correct syntax and there’s a smart tab in the left column that allows you to track and view the different variables, functions and classes in the projects and code. Navigation through the code is fairly simple via contextsensitive menus and nice options within the rest of the interface, and the usual code-editing tools such as commenting out a selection or indenting are all present.

n Geany’s interface is smart and easily breaks down code for workflow purposes

“Code is automatically highlighted with the correct syntax” Sadly, Geany’s plug-in support is pretty dire. Some plug-ins extend the basic functionality for a few of the languages, but there’s not the kind of depth as Netbeans or Eclipse in the sheer number of available plug-ins. There are a lot of ways to customise Geany with the standard tools and menus, though. Almost every part of the interface and workflow is editable, with ways to even change the characters required for autocomplete suggestions.

n The native languages are supported quite well with compilers and such


Geany is a very smart IDE, with a low barrier to getting your project started straight away. It does lack in some of the features of some of the bigger IDEs, such as more advanced unit testing and debugging, although it will let you browse compile errors. The plug-in selection is also pretty poor, so it may not be extensible for specific functions.

SCORES Installation

Readily available in most repos and requires minimal dependencies

Workflow

Workflow is superb for the variety of different languages included

9 9

Features

No proper debugger, but a great selection of build and project management functions

7

Plug-in support

Although it doesn’t quite need it like the others, there are very few plug-ins available

4

Overall

Geany is a great, lightweight IDE with good native support for a variety of languages, but there’s not much room for expansion

8



REvIEW

Eclipse

The ubiquitous Eclipse is an industry standard – how does it fare against more community-run efforts?

Eclipse is one of the most popular development suites around, and at first glance it’s easy to see why. While created mainly for Java development, Eclipse is highly customisable through plug‑ins. Thanks to its popularity and community, this has resulted in a great selection of add‑ons that enables Eclipse to work with just about any language. These plug‑ins allow for more than that, with a marketplace full of interface and behavioural modifications alongside the language elements. Eclipse has great project management tools as well, with a smart tabbed interface, and plug‑in‑specific menu entries for starting projects in different IDEs if needed. Projects are located in plain folders in the location of your choice, allowing for easy access of source code if you need it, instead of being inside a proprietary file. The function search ability works well and the interface has plenty of tips and warnings for

n Plug-in support for Eclipse is top-notch

anything that might be inefficient in terms of the code. There are plenty of editing tools too, such as simple indent or dedent options. The debug suite in Eclipse is fully featured, with various ways to run, check and unit‑test code, although this depends on the plug‑ins to some degree. The tools are there, though, and most of the major plug‑ins seem to use them. The plug‑ins are handled by a repository system, which lets you keep any add‑ons up to date. While there aren’t a huge amount available by default, it’s easy enough to add more to the plug‑in manager and you can even

“A great selection of add-ons enables it to work with just about any language”

n Code navigation and highlighting aids your workflow

select which extensions to install from each of the repositories. Eclipse is customisable in other regards, with an expansive properties and settings menu that lets you edit a huge amount of the native behaviour of the IDE, from the way patches are viewed to little things like key bindings and other shortcuts. Eclipse is a fairly big suite of packages, though, and easily the biggest resource hog out of all of the IDEs we’re testing. It does have probably the best extensibility of all these IDEs, however, meaning it also probably has the most to offer those who work on a lot of differing projects.

SCORES

Installation

Eclipse requires a lot of dependencies; however, it’s available in most major repos

7

Workflow

Smart interface design that lets you easily navigate projects and code

9

Features

A great set of features by default, although mainly for handling Java

8

Plug-in support

The best support around, with a great repo system offering a wealth of add-ons

10

Overall

Eclipse is popular for a reason – its got a great selection of features that are easily extensible to suit almost any need

9


Review


Netbeans

The Oracle-developed Java development platform that multitasks

Netbeans started life as a humble student project to make a Java IDE in Prague. Within a few years, a company had been set up around the IDE, and then had been bought by Sun Microsystems. The rest is history and after over 15 years of development, Netbeans is on version 7.3. Netbeans has a very similar feature-set to Eclipse, with debuggers, compilers, unit testers and the like, although by default Netbeans has support for PHP and HTML as well as its Java-specific features. Netbeans also has a huge database of plug-ins to call from, allowing you to extend its features to just about any programming language. These plug-ins are nicely arranged in a database format on the Netbeans website, with simple search functions and a fairly easy way to install the plug-ins to the system. There’s no repository function for the plug-ins like Eclipse, but the database displays enough information to know if you’re getting the latest version of the plug-in. The interface is a little confusing – not very well streamlined and aesthetically a little dated. While the splash screen is nice for starting new projects, the rest of the interface is cluttered

n The interface is not particularly well laid out


n Netbeans has a nice welcome screen to start new projects

“There just isn’t quite the same level of customisation as Eclipse or the others” and some functions are hidden away in weird menu options. The code view is not particularly well handled, with syntax highlighting a little sparse. The function navigator is fairly nice, though, with the sidebar allowing you to track the hierarchy a little better than some. Customisation in Netbeans is handled with a nice-looking options menu, but there just isn’t quite the same level of customisation as Eclipse or the others. However, for similar customisation tasks, it’s a little better laid out than Eclipse.

Overall, Netbeans seems like it’s a little behind the times, with an interface that needs a small overhaul and a better selection of customisation options. It’s by no means a bad IDE, with a great suite of debugging and testing options to use on code. On the other hand, Eclipse is equal or better in almost every regard.

SCORES

Installation

Packages are readily available for Netbeans and it requires a Java install

8

Workflow

The interface is a little cluttered and convoluted, but there are some decent options to be found

7

Features

A similar feature-set to Eclipse, but not as much customisation

7

Plug-in support

A fairly large selection of plug-ins are available for it within an easy-tosearch database

8

Overall

Netbeans just misses the mark with a slightly dated interface, but it’s made up for somewhat with a good selection of plug-ins

7



rEvIEW

In brief: Compare and contrast our verdicts Installation

Workflow

Code::Blocks

Geany

Eclipse

Netbeans

Available in repos and via binaries on the website

Requires few dependencies and easy to come by

A big suite of packages, but readily available

7

In most major repos and doesn’t have many dependencies

8

9

A nice workflow view, but the interface is a little dated

7

Good for the languages that are supported A decent selection of features for C++

Features

Plug-in support

Overall

Code::Blocks’ plug-in support is immature and badly distributed A bit disappointing as of yet, but Code::Blocks shows some potential

8 7 7 4

6

AND thE WINNEr Is… Eclipse

We were actually a little surprised that Eclipse was this good compared to the other IDEs in this month’s group test. It offers excellent project management features, while its hugely expansive plug-in list means that you can make it work just about any way you want it to – much more so than Geany or Code::Blocks. Geany is definitely a close runner-up, though, and while we’re not specifically looking at lightweight IDEs this time, it does have a great selection of features while being light on system resources. The only thing that really let it, and Code:Blocks, down was its lack of plug-in support. Code::Blocks still needs some development time, and more community involvement, to make it a truly great IDE. It’s good to work with for C++ for now, and we’d recommend it for that, but it just doesn’t have enough to recommend it for multi-language work. Eclipse, on the other hand, has a great balance of all the aspects we’re looking for in a multi-language IDE and that’s why it takes the editor’s choice award. Rob Zwetsloot

Great workflow ideas, with easy code navigation There’s not a proper debugger for Geany

Geany does not have many available plug-ins A great lightweight IDE that may not be the best, but it’s still recommended

9 9 7 4

8

Project management is excellent and code navigation is good Eclipse is a featurefull IDE and is highly customisable Eclipse has the best selection of plug-ins in this test by a long way Ubiquitous for a reason, Eclipse has a lot of things going for it

8 10

9

A decent debugger and reasonable customisation A huge database of plug-ins, although some are a bit old Netbeans just falls short of the other IDEs with some missing features

7 8

7

“Offers excellent project management features and a GROUP TEST hugely expansive plug-in list WINNER to work any way you want” www.linuxuser.co.uk

n Eclipse can be anything you want it to be


Nook HD+

Low-cost Android tablet

REVIEW

■ The display has a high pixel density and is great for reading eBooks and watching videos. We would have preferred a bit more brightness to it

TABLET

■ The hole in the

corner is a Nook trademark. We can’t say whether it is supposed to be functional or not

■ The Nook has a fully customised skin, but does have access to the full range of Google apps, plus the Play Store, so you can Android-it-up a bit more

Nook HD+ £179

Technical specs Operating system Processor Memory Dimensions Weight Display size Display resolution Expansion slot

Android 4.0 1.5GHz dual-core 1GB RAM, 16-32GB storage 240.3 x 162.8 x 11.4mm 515g 9-inch 1920 x 1280 pixels microSD

Is this low-cost, hi-res tablet alternative to the Kindle Fire an Android hacker’s dream device? With the future of the Nook brand looking decidedly murky, it may not seem like the best time to be investing in one of its tablets. Or maybe it is. With price drops aplenty, Barnes and Noble’s answer to the Kindle Fire represents perhaps the cheapest way to get a high-quality tablet – hi-res display, fast performance and full Play Store access. It’s also fully hackable, so even if you don’t like the Nook’s UI you can switch it to proper Android. The Nook HD+, with its 9-inch display, feels pretty good in the hand with solid construction and weighty feel. The design is distinctive in good and bad ways. A large bezel around the screen is not as offensive as it might have been, while the ‘n’shaped Home button gives the tablet subtle branding. On the downside is the weird hole in the bottom corner that serves no apparent purpose. It looks as though you’re supposed to attach a lanyard, but the tablet is far too big and heavy for that to be practical. The screen is the Nook’s standout feature. With a resolution of 1920x1280, a pixel density of 257ppi, it is close to the level of the Retina display on the iPad and is wonderful. Text is sharp and crisp and it is very easy on the eyes. We did find the screen to be lacking in brightness, however. Perhaps this is because the tablet is intended primarily as an eReader and so needs to have less glare, but for general use we had the brightness cranked up to the max, and would have preferred even more.

The software is also built for eBooks. Like Amazon’s Kindle Fire series the bulk of the UI is built around encouraging you to buy content, but unlike with the Kindle you do get the full set of Google apps, and Play Store access as well. There are a number of apps pre-installed, ranging from Spotify to Pinterest to a crosswords app, and none of these can be removed. You will need a Nook account before you can start using the tablet, and will also need your Google account details to access the Play Store. With a bit of work you can get the Nook looking pretty much like a normal skinned Android 4.0 tablet. We wouldn’t count on getting OS updates, but it is rootable and there are Jelly Bean ROMs available. There’s a good chance there will be KitKat (Android 4.4) ROMs in future too. Sandra Vogel

Pros

Great screen and exemplary battery life; quite hackable too

Cons

Pre-installed apps can’t be removed; some strange design decisions

Summary

The Nook HD+ is a pretty good device. With nice hardware and a good display, it’s surprisingly flexible: you can use it as a casual eBook optimised tablet, for the full set of Android apps, or open it up to hacks and tweaks.

More information www.nook.co.uk


Review

RasWIK

n There is no passthrough for the Pi’s spare GPIO pins, sadly

n A small chip provides the Pi with a radio for wireless communications

n The small ceramic antenna can be replaced with a wire whip to boost range

n While small, the Slice of Radio does block the little-used Display Serial Interface (DSI) connector

PeRIPheRAl

Raspberry Pi Wireless Inventors Kit £49.99

www.linuxuser.co.uk

EDITORS’

CHOICE

Designed to mate a wireless Arduino microcontroller with the Raspberry Pi, is the RasWIK what budding developers have been waiting for all this time?

Pros

The easiest way to get started with wireless microcontroller development using the Raspberry Pi

Cons

The LLAP wireless protocol offers no encryption; Slice of Radio blocks unused pins on the Pi’s GPIO header

While it’s easy to see the Arduino and the Raspberry Pi as competitors – they’re both low-cost electronic devices aimed at the hobbyist market, after all – in truth they’re extremely complementary: the Arduino excels at real-time control and sensing, while the Pi provides cheap network connectivity and powerful data processing capabilities. That’s clearly been the thinking of Ciseco in designing the Raspberry Pi Wireless Inventors Kit, or RasWIK: a bundle of components and accessories, it’s designed to make working with the Arduino on the Raspberry Pi as simple as possible and showing users just what potential is opened up when the two are connected over a radio link.


Getting started couldn’t be easier: the kit includes a 4GB SD card with a customised version of the Raspbian operating system. Simply slide this into the Pi, pop the bundled Slice of Radio board onto the GPIO header and apply power. The SD card includes an open source example utility for controlling the included Arduino clone, a radio-equipped microcontroller dubbed the XinoRF. Using this tool, a visual representation of the board appears on screen – and allows the user to turn outputs on and off, or read values from digital or analogue input pins. With nothing connected to the Arduino, that would soon get pretty boring, but the kit also includes numerous

RasWIK

Wireless microcontroller connection kit for Pi

Review

Technical specs

nMost

Operating system RaspianLinux Dimensions (XinoRF) 70.9x53.3mm weight (XinoRF) 25g Dimensions (Slice of Radio) 30.3x34.3mm weight (Slice of Radio) 7g extras 4GBSDcard,USBcable, smallbreadboard,5xred, yellowandgreenLEDs, 30xresistors,lightsensor, thermistor,piezoelectric buzzer,3xpush-button switches,25xjumperwires

existing Arduino shieldswork finewiththe XinoRF

nTheAtmel Atmega-328 provides fullArduino compatibility

nThesamecompact radioboardisfoundon theXinoRFasonthe SliceofRadio

nTheXinoRFcanbe

poweredbyamains adaptororthrough mini-USB components and instructions for various experiments and small projects. Using the bundled compact breadboard, it’s possible to get building simple circuits – remote buzzers, traffic lights, even a light and temperature sensor – in mere minutes. The RasWIK has a serious trick up its sleeve once your device is built: an embedded radio on the XinoRF connects to the Slice of Radio with no effort, allowing you to place the XinoRF almost anywhere in the same building as the Raspberry Pi and still take control of it. The system uses the Lightweight Local Automation Protocol (LLAP), which allows for multiple devices on the same radio network – more XinoRFs, more Raspberry Pis, or some of the LLAPcompatible accessories also sold by Ciseco. It’s here where the only real downside of the kit comes to light, however: LLAP is extremely lightweight, as you might expect from a protocol designed for a microcontroller with around 32KB of program storage. Accordingly, it includes no protection against intrusion; so if your neighbour buys a RasWIK kit, he or she would be quite able to take control of anything you build. For the experimenter, though, it’s a minor point. While the kit runs LLAP out of the box, the radio can also be used as a point-to-point serial connection, and you can write your own protocol to run over the top if you desire robust security. That minor issue aside, there’s little not to like about the RasWIK kit. The radios offer surprising range, and the Slice

of Radio in particular is a very clever bit of design and sits happily on top of the Pi’s GPIO port without increasing its dimensions – meaning it can be used in conjunction with the vast majority of non-metal cases on the market. The only real downside for those who enjoy experimenting with the Pi’s GPIO hardware is that the Slice of Radio does not include pass-through connections for the other pins on the header, despite only using power and the UART connection itself. Careful work with a soldering iron will allow you to fix that, but if you’re not happy with such modifications and have only one Pi, you’ll soon grow tired of removing the radio board in favour of other GPIO-connected devices you may have. Gareth Halfacree

Summary AlthoughitwouldbeeasytomarktheRasWIKdownforits insecureprotocol,todosomissesthepoint:it’saneasyway to get started with wireless microcontroller development, andprovidesagreatplatformforaddingsensorsoractuators toaRaspberryPi.Ifsecurityisaworry,userscanalwaysroll theirownprotocol.

Also consider

ARDX experimenter’s Kit £62

Anopensourcekit, Oomlout’sARDXisthe bestwaytogetstarted withArduinodevelopment. Whileitincludesmore componentsthanthe RasWIK–includinga mountingplate,servoand motor–itdoesnotinclude anywirelesscapabilities asstandard.Thesecan, however,beaddedata laterdate. www.oomlout.co.uk

Gertboard £31.12

Oneofthefirstadd-on boardsdevelopedforthe Pi,theGertboardisawired GPIOexpansionmodule. Notentirelysuitable forbeginnersdueto inaccessiblecodeexamples andawkwardhardware, it’sstillanaffordable wayofincreasingthePi’s GPIOcapabilities–but, again,hasnointegrated wirelesshardware. uk.farnell.com

More information ciseco.co.uk


Review

SparkyLinux 3.0

New features: Debian 7.0 • Linux kernel 3.9.8 • GNOME 3.8 compatible

n Customised desktop environments such as LXDE, Openbox and MATE are available

n The preset Conky display gives a lot of information about your system, all of it relevant

n The SparkyCenter is a nice little app for controlling your system, although it could do with better navigation

diStRo

SparkyLinux 3.0

Minimum Specs: CPU 1GHz i486 RAM 256MB (128MB for CLI Edition) StoRAge 5GB (2GB for CLI Edition) Best for: Home office

One of the first distros using Debian 7.0 ‘Jessie’, SparkyLinux is positioning itself as a lightweight system for any user Pros

Lightweight distro based on new testing branch of Debian; nice aesthetic; great selection of images

Cons

Doesn’t play nice with all desktops; some issues with Flash and JS on non-Iceweasel browsers

SparkyLinux is a relatively new distro, with its first version only coming out in May of last year. Since then, its gone through a few major upgrades and number changes and is now on its third iteration. The idea is to create a lightweight distro that computers both old and new can use – with modern aesthetics and graphical features available for those with high system specs. In case you don’t need graphics at all, though, there is a handy CLI image that reduces the specs down further – another first for a Debian 7.0-based distro. Graphical images come in several flavours: the standard lightweight LXDE image, a purely Openbox-based image, a MATE image and a Razor-Qt running edition. These are all customised to fit the needs of Sparky, with a dock added


in most cases, along with a nice custom theme. All of the live images include both a graphical and a command-line installer – as used in the CLI version. Both work exactly the same way with the exact same options; however, the command-line version uses cfdisk for partitioning, and the graphical installer used GParted. It’s a minor difference that can actually cause a unique issue – SparkyLinux can’t detect partitions on a hard drive that uses GPT. This means that systems with UEFI may need to be wiped before installing. As GParted can work with GPT, you may never know that this is an issue, as no warning messages or errors are thrown up. This also means that partitioning for SparkyLinux is completely manual. It does explain what it needs to run, and

SparkyLinux 3.0

Debian 7.0-based lightweight distro

Review

n Unlike a lot of modern distros, the installer has you manually partition the hard drive – although there are decent instructions on how to do it

n Synaptic grants you access to the entire Debian repos – although we had some issues with using apps and other packages we installed to it

Partitioning for SparkyLinux is completely manual

n It’s a rolling release based on testing Debian, so all the latest software is available to use in Sparky

the Sparky website has some nice instructions to help you along the way, but the graphical installer could be improved by having the auto-partitioning of other modern distros. Other than these issues, installation is quick and relatively painless and while the majority of people won’t face the GPT problem, it’s something that will become more problematic as more and more systems use it.

are featured on the dock with a couple of other apps, and Synaptic is used as the main package manager. While we had no issues with Iceweasel on some websites, when we tried using Chromium, Flash or JavaScript, heavy sites would basically break the browser – including even the Chromium store. Tabs could be exited and reopened; however, the same problems would happen consistently.

Unique aesthetic

it shouldn’t happen

The default login manager is very simple: a drop-down list for users, and a few options in the corner hidden away that let you change the locale and desktop session. Nothing fancy. However, the default desktops each have an aesthetic quality unique to SparkyLinux. A nice use of monochrome icons and colours class up the desktop, and the dock included with LXDE increases its usability. There’s also a preconfigured Conky display that gives a great selection of system information. This is also present in the live image, just in case you need to keep an eye on your system. SparkyLinux has a great graphical system manager, similar to the likes of Mageia, albeit not as well laid out or as deep. The SparkyCenter gives you access to change the theme and overall look of the distro, software sources, Flash and Java settings, default applications, hard drive management etc. The interface is presented in icons that move into different layers and while there’s no back button, exiting the window will take you back a step. The default app selection was nice, although with no commitment to truly free software. VLC, GIMP and Iceweasel

That also wasn’t the only extra package we had issues with – trying to install Cinnamon went terribly, with only a patchy black screen showing up when trying to boot into it. This really shouldn’t happen, even if its not available as a default desktop. At the very least, the default desktops all work well, especially the Razor-Qt offering which is fast becoming one of our favourite lightweight desktops. Being Debian based, the repos are of course full of all the latest and greatest software. The reason SparkyLinux has iterated so much is because it’s considered a rolling release – basically updated with snapshots from Debian testing at specific intervals. This should mean that Sparky is always up to date if you like to be on the cutting edge. However, we don’t think it’s worth it. Being severely limited to basically the default applications and desktops, however good they are, is not the Linux way. It’s worth a look, but don’t get your hopes up. Rob Zwetsloot

Screenshot Gallery

bit.ly/LUDSL3

Summary There are some great ideas in SparkyLinux, and it works very well – unless you decide to step a bit outside the predefined barriers of apps and desktops. Well worth a look, but it’s not for everyone.

Dowload now sparkylinux.org


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Book Reviews

Latest Linux books revealed

REVIEWS

Burn Your Portfolio:

Stuff They Don’t Teach You in Design School, But Should Authors Publisher ISBN Price Score

Fast-paced real-world Scala tutorial

Michael Janda New Riders 978-0321918680 £22.99

Sage advice for all creatives – programmers and web designers, not just artists and illustrators – that should be common sense, but comes (if at all) from decades of experience. It’s never too late to learn – improve your work and your workplace with Janda’s blogpost-sized bites of wisdom.

Vagrant: Up and Running Author

Mitchell Hashimoto Publisher O’Reilly ISBN 978-1449335830 Price £22.99 Score

Virtual development environments the easy way, with two commands to get a virtual machine up, then easy sync of complex development environments. Automated provisioning includes Chef, Puppet and shell script options. Vagrant creator Hashimoto expounds, explains, and expands – including a section on writing plug-ins.

Functional JavaScript:

Introducing Functional Programming with Underscore.js Author Publisher ISBN Price Score

Scala in Action

Michael Fogus O’Reilly 978-1449360726 £22.99

The near-ubiquity of JavaScript in the web age makes it a good platform for teaching functional programming techniques, while applying functional concepts to JavaScript will improve your apps in many ways – though functional programming people looking to learn JS may need an additional guide.

Authors Publisher ISBN Price Score

Nilanjan Raychaudhuri Manning 978-1935182757 £28.99

Scala is gaining many new users, attracted by its convenience (runs on JVM and .NET); OO implementation (modelled on Smalltalk and Eiffel); functional programming features (though it does not force any aspect of this – such as immutable data – on the coder); scalability (readily extensible, yet suitable for smaller scripting jobs); sane concurrency (through Erlang-style Actors implemented in libraries); productivity (say goodbye to ugly Java boilerplate); type inference; and compatibility with Java libraries. Raychaudhuri evangelises these features, but quickly gets you to practical appreciation as in chapter 2 you build a command-line REST client, and in chapter 3 you code a MongoDB driver using Scala classes and traits. Functional data structures make a logical stepping stone to functional programming, and the book stays practical with web apps, databases and concurrent programming. Testing, Java interoperability, and scalable distribution with Akka round off this excellent, fast-paced (if you want good-butgentle, try Odersky) tutorial.

Arduino Adventures:

Escape From Gemini Station Fun and imaginitive Arduino inroduction Authors

James Floyd Kelly & Harold Timmis Publisher APress ISBN 978-1430246053 Price £23.50 Score

Framing an Arduino tutorial in a science-fiction story is a big risk. Fortunately, Timmis and Kelly have made both story and tutorial work, as their engaging characters get caught in an adventure that can only be survived with the help of some creative, breadboard-based, hardware hacking – something they must learn from scratch, along with the reader. An imaginative way of justifying the various beginner projects which can build knowledge both of electronics, and of Arduino programming, this book should carry young minds easily past some new concepts, and through the acquisition of a number of skills. Fiction, theory, hardware and software through eight challenges, from simple potentiometer and LED projects, through temperature and motion detection, to building your own robot. Rounded off by a comprehensive parts list for each project, and the advice: “Never stop learning.” Recommended for any beginner, of any age, wanting to start learning Arduino.

Emergent Design:

The Evolutionary Nature of Professional Software Development Improve old code & professionalise programming Author Publisher ISBN Price Score

Scott L Bain Addison Wesley 978-0321889065 £38.99

A profession – an agreed-upon set of minimal standards, and a clear path of entry – is not a way of describing software development, but Scott Bain would like it to be and, with Emergent Design, sets out his view of the standards to “improve our lot as creators of software”. To make (inevitable) change an opportunity, Emergent Design leans heavily on Gang-ofFour patterns and refactoring (with attention to coupling, cohesion, redundancy, readability, testability) – so Bain concentrates exclusively on object-oriented languages and techniques. Missing is the functional programming view (most G-o-F patterns are unnecessary in FP languages), but this book is valuable for the questions it asks, and its (practical) optimism: “An old concept that I used to accept – code must inevitably decay over time – fades away in favour of something more hopeful: code can evolve over time, getting better and better every time I touch it.”


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Your questions

answered

ASK THE EXPERTS

Send us your questions and we’ll do our best to answer them!

This month your questions were answered by…

Russell Barnes has been a computer and technology journalist for nearly 15 years

Rob Zwetsloot studied

aerospace engineering, using Python to model simulations

■ Clonezilla is a powerful disc imaging tool

How do I compile software?

Compiling software from source code isn’t that difficult – all it requires are simple build tools available in all repos. To make sure you have the correct build tools installed, do the following in a Debian-based system:

Kunal Deo is a veteran

developer of many open source projects

$ sudo apt-get install buildessentials Alternatively, for other systems, use:

$ sudo yum groupinstall 'Development Tools'

Richard Smedley spends 90% of his screen time shelled into servers in the UK and USA


Once you have the necessary source code for the software you want to compile, navigate to the folder in the terminal and type:

$ ./configure

…to build the files, and follow up with:

$ make ….to compile it.

Ghost editing

Hi there. I’ve been playing around with my system recently, and decided to do a small overhaul of my disc setup. I created a ghost of my main hard drive, which was not full, and am now attempting to apply it to a smaller space than it was originally on. I figure because the image wasn’t full up anyway (and there was no important data I’ll lose if I start messing about with it) that I can make some changes to the file and be able to apply it to the new disc I want it to be on? Hope you have some answers. Joe O’Reilly

Questions & answers

All your technical problems solved

Q/A

It’s certainly possible to do this, and it doesn’t require a huge amount of messing around to accomplish either. First of all, boot into a live Linux environment from a disc or USB storage. Use fdisk -l and make a note of the cylinders, heads and sectors, and then edit the image file sda-chs.sf with these new details. Next, use:

$ parted /dev/sda 'unit s' print …noting down the first few lines, and then edit the file sda-pt.parted to match this. Finally, sync/restart and the restore the image with Clonezilla and you should be all set. Next time, you could always shrink a partition to fit the destination before cloning, which should make it a little easier.

Converted

I’ve been trying to follow a guide on converting an MKV to an AVI using MEncoder. It seems to work just fine, but I keep getting problems where it just plays the audio on some devices. Here’s what I’m doing to convert the video, by the way:

$ mencoder abc.mkv -oac pcm -ovc xvid -xvidencopts bitrate=886 -sub ITC0101.srt -subfont-text-scale 3 -o zzz.avi

and you can do so with the following commands:

$ ffmpeg -i input.mkv -vcodec libxvid -qscale 5 -s 640x272 -aspect 40:17 -r 23.976 -g 240 -bf 2 -acodec libmp3lame -ab 160k -ar 48000 -async 48000 -ac 2 -pass 1 -an -f rawvideo -y /dev/null $ ffmpeg -i input.mkv -vcodec libxvid -qscale 5 -s 640x272 -aspect 40:17 -r 23.976 -g 240 -bf 2 -acodec libmp3lame -ab 160k -ar 48000 -async 48000 -ac 2 -pass 2 -f avi outlander-q5.avi This should give you a little more control over what you’re outputting, and hopefully work a bit better with your DVD player.

Batch download

Every now and then I come across a website directory that has a load of individual files I need to download residing within it. I used to use a Firefox add-on to select and download them all in one. However, I wanted to know if there’s a more universal way of me doing it without having to get extra add-ons for my browser? Colin Still

It works fine on my PC, but on my DVD player, which has no problem with these codecs usually as far as I’m aware, it just doesn’t work. Am I missing something with my command, or is there another way I should be going about doing this? Tim Daley No, your command seems to be fine, it’s most likely an issue with MEncoder and the limited codecs on the DVD player. You might be better off trying FFmpeg, though,

n Not everything has the latest codecs

n Web directories can be easily downloaded

from using wget

It’s most likely an issue with MEncoder and the limited codecs on the DVD player

Minty Apple My parents have finally decided to join this century and get a proper computer rather than relying on me or library computers to get their information. As family tech support, I’ve told them I’ll get them set up with a new system they can use for emails and such. Because they’ve never really used computers much at all, I wanted to set up a Linux Mint system for them. However, the only issue I have is finding spare hardware to get that going. I did find that I have a Mac Mini lying around, though… so I thought about putting Linux on that. However, I seem to recall it’s not as easy as just putting the live disc in and installing as I found out. I’m not too bothered about losing OS X, and would much prefer my parents use Mint anyway. How do I get it installed on there? Jeff Vincent While Mint and its Ubuntu base have tools to install on Secure Boot systems that use UEFI, it requires the use of legacy modes to get it work normally. But we don’t have that luxury with a Mac, so you need to do a little more. The main issue is that it uses a different partition table that won’t work with Mint, so the easiest thing to do if you don’t mind losing OS X is convert it to something more Linux friendly. Make sure any files you want to keep are backed up, as this method will format the hard drive. Burn a live CD or DVD of Mint and put it in your optical drive. Restart the Mac and hold down the Option key to bring up the boot selection screen, and of course select CD. Boot into the live environment by choosing Try Linux Mint. When Mint loads up, you’ll next need to open GParted. By default it should select the Mac’s hard drive, so click Device on the menu bar and then go to Create Partition Table. A warning will pop up, and then you’ll want to click the Advanced triangle. From here you’ll be able to create a new partition table format, this time as MS-DOS. After that is done, you can install Linux Mint however you wish. We’d suggest using Cinnamon if your parents are more used to Windows systems, and show them how to install apps from the Software Centre.


Questions & answers

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One method we’d recommend using on Linux would be wget, the standard downloading tool for the command line. You can download the contents of a web directory with something like:

$ wget --mirror -p --convert-links -P /destination/folder/ http://www. websitre.com/directory/ You can also use curl as well. This can also be used with single files if you find yourself without a browser to use.

■ Battery management is not always easy

Assault on battery

I want to have a notification show up in the event that my laptop battery charge falls below 10%, as I regularly move around when working on it. I guess that most desktop environments provide a notification of this sort, but I use xmonad with a few other programs, so I just need something like a notification daemon and front-end. I’ve had a few close calls while working so far, and I’d really rather not go back to a desktop environment if I don’t have to. Can you suggest any notification tools? I would prefer a lightweight package that I can extend with other notifications, but any suggestions are welcome. If there are any DE notification tools that work well outside of their environments, that would also do. Chris Dodd

■ Make sure Java knows where itself is located

how do I go about setting up my system to use the Oracle JDK? I’m currently running Ubuntu. Thanks.

Now you need to run some specific commands to update the system Java info, allowing you to then switch to it. First of all do:

Peter Chan

$ sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/ jvm/jdk1.7.0/bin/java" 1

There’s actually a couple of great tools you can use on xmonad to get this type of functionality. You can use i3, which is a tiling window manager, which can be used on its own or in conjunction with twmn. Both offer tiling notification windows, and i3 is specifically designed to work with the xmobar as well. i3 is also very extendable, and it can be used for a lot more than just battery notifications. Hope this helps.

Okay, so the process for doing this is a two-step one. Firstly, you need to download the JDK files from the Oracle website, which come in a tarball. Extract these and this will create a ./jdk.1.7.0_0x directory in the location of your choosing.

Oracle of Java

Now create a new directory for it and move into it with:

So I have the OpenJDK installed on my system, and it turns out I need to use the official Oracle JDK for a project I’m working on. Only, it seems like I can’t just install it and expect it to work –

$ sudo mkdir -p /usr/lib/jvm $ sudo mv ./jdk.1.7.0[Current Version] /usr/lib/jvm/jdk1.7.0


$ sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/ jvm/jdk1.7.0/bin/javac" 1 $ sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/ lib/jvm/jdk1.7.0/bin/javaws" 1 Now, correct the file ownership and the permissions of the executables with:

$ sudo chmod a+x /usr/bin/java

Questions & answers

All your technical problems solved

Q/A

n When connecting remotely, some settings n The right drivers don’t always produce the right response

$ sudo chmod a+x /usr/bin/javac

…and then enter the following into it:

$ sudo chmod a+x /usr/bin/javaws

/usr/lib/jvm/java-7-openjdk-amd64/ jre/lib/amd64 /usr/lib/xulrunner-17.0

$ sudo chown -R root:root /usr/lib/ jvm/jdk1.7.0 Now we need to select the new JDK by running:

$ sudo update-alternatives --config java You’ll be shown a list with numbers from which to choose the new JDK from – make sure to choose the one we’ve been setting up. Now we can make sure it’s done properly by checking the Java version with:

$ java -version You can now also switch back to OpenJDK, if you need to, with the config java command.

Graphical Java I’ve just upgraded my box to the Radeon drivers, and it’s so far proved to be a good idea. The box runs smoothly now. There are some issues with Java OpenJDK, though. How do I get it to use OpenGL? There may well be the option to use Sun’s Java, but it needs AOSS – so, either I tweak the OpenJDK to not crash and use OpenGL/acceleration; or I use Sun’s JRE, but it would involve installing OSS. Chris Kimpton You’re going to have to use a little hack so that Java knows where it’s located. Create it with:

$ nano /etc/ld.so.conf.d/ javaworkaround.conf

…and run ldconfig as root. Choose /home for the user and libnpjp2.so file locations. The Oracle and OpenJDK versions of Java are linked to PulseAudio, so sound-wise you’re better off using PulseAudio. There’s some Java OpenGL packages, too, that you might want to install with:

are different for displays

Open the terminal while logged in as root, and then change to another user

$ dpkg-query --load-avail -l '*jogl*' Hopefully that should fix things up for you.

Terminal trouble

I’m experiencing a very weird problem – every now and then I need to do some work in the terminal on my system. However, whenever I try and open the terminal emulator, it opens for a brief instant and then automatically closes. The system in question is CentOS, which I have to access remotely via VNC. It’s using Xfce as a desktop environment as well. The weird thing is, it works just fine if I’m logged in as root, so I can only assume it’s a problem with the user type. Obviously, I don’t want to make some of the normal users have full root privileges, and I’d much rather not log in as root every time I work on this system. Have you heard of anything like this before? Is there something fairly obvious that I’m missing? Thanks for any help. Thomas Reid

As root works, here’s a little thing you can try – open the terminal while logged in as root, and then change to another user with:

$ su -l This will allow you to open another shell to log in with and then try to open the terminal. Any errors will show up in the root terminal. What may likely happen is that you cannot even load into the shell. This is because the user will not have access to connect to the X server because you’re using it via VNC. To solve this, you just need to add the relevant users to the list that are allowed to make this connection. You can do this with xhost by typing:

# xhost local: …as root. Give the system a reboot and it should now be working fine.


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Your view

Your source of Linux news and views Contact us…

Register and post your comments… www.linuxuser.co.uk/forum/


YOUR VIEW

Linux User Letters Your opinions about the magazine, Linux and open source

Piece of Pisi

I remember a while ago you talked about Pisi Linux, an alternative to Pardus that was a bit more like the original. I was sad to see that DistroWatch refuses to even list Pisi Linux because someone trolled them, telling them it was not active, setting up fake Pisi Linux sites etc. DistroWatch apparently decided they would remove it from their lists. Very sad and disappointing on the part of DistroWatch. I hope that when it finally

■ Pisi Linux is currently in beta

reaches stable release they’ll add Pisi back to the database, as the older Parduses were some of my favourite distros! Mark Doyle It’s a shame that DistroWatch took the stance. Going by the Pisi team’s side of the

story, it seems like DistroWatch were duped; however, the folks over at DistroWatch haven’t responded to the Pisi team since their explanation. The beta for it is out now, but Pisi is not back on DistroWatch just yet. Look out for a review of the full version when it’s finally released.

THREAD BARE

Way of the future Things are heating up in the display server space, as both Wayland and Canonical’s Mir are set to try to replace the X server shortly. Richard Hillesley’s piece on Wayland in issue 127 inspired some debate on the website about replacing X. Join in the conversation here: bit.ly/LUDWay

Henrik Danielson said: Wayland was supposed to be that common protocol/API. As far as I can tell, one problem is that Mir is intentionally incompatible with Wayland.

Bob Robert said: I use the network display functionality of X on a regular basis. The switch to Wayland is fine by me (I’m a user, not a programmer) so long as I can still ‘ssh -Y’ and launch GUI applications that display on my local machine. That X did network transparency ‘mainline’ and Wayland would do it with a ‘plug-in’ is actually unimportant to me. What matters is that it DOES it. It is functionality I use, and want.

bwat47 said …I don’t think the situation is quite as bad as it seems. Both Mir and Wayland have several major similarities in their architecture, such as using EGL. For drivers, theoretically it should not be difficult to support both as long as they provide EGL support. For applications


■ Wayland is intended as a simpler replacement for X

things shouldn’t be that bad either, because Mir/Wayland support is at the toolkit level. The biggest burden will probably be on the toolkits, though: having to have and support two back-ends in addition to X (because X will not be totally going away any time soon).

Gene Mosher said: Keith Packard asks: “How many of these applications care about network transparency, which was one of the original headline features of X? How many of them care about ICCCM compliance? How many of them care about X at all? The answer to all of those questions, of course, is ‘very few’.” And if we all are among the ‘very few’, then what does the future hold for us, Keith?

Your view

Pisi Linux, Wayland vs Mir, Specialist distros, Pi projects

LETTERS

Android Magazine

With more and more Android features being merged back into the Linux kernel, it’s becoming easier to develop for one of the most popular mobile operating systems around. With over 25 billion app downloads, and over 500 million Android devices worldwide, there’s a huge audience ready to consume apps. For a more Android-driven editorial, look to our sister mag Android Magazine, the only publication dedicated to the platform. Along with news and reviews to keep you up to date on everything Android, there are also tutorials and advice on developing and hacking your hardware. Find out more at www.littlegreenrobot.co.uk.

■ Some specialist distros are more than a selection of apps

Specialist distros Okay, I am a little confused with the whole distro designed for specific job trend. If I want to run audio applications in Windows, Mac or any other OS, I install the programs I want. Why oh why with Linux do we see this approach of “just install the audio distro for the best audio environment”. What a waste! Instead of customising an existing distro and having a nice ‘aptitude/yum install audio-env’ we get all the overhead of maintaining a distro just for the applications? Isn’t it time we separated the application from the OS and ignored any attempts by people to integrate the two? Colin McDermott There’s no specific reason why you can’t do this anyway – a lot of people will probably be fine with a standard Fedora or Ubuntu install for any of their specialised needs. However, some distros do more than just come with a selection of themed default packages – distros like AV Linux go the extra mile and customise the kernel specifically for AV software. Not everyone has the skills to do that in Linux, so these kind of distros do serve a purpose. The same with some lightweight distros. It’s about choice, and this offers a lot more choice for people.

More Pi

I’ve just finished reading issue 129 of your magazine and was very inspired by the ten

Raspberry Pi projects you had. I tried out a couple of them and was pleased with the results; there are really so many things you can do with the Raspberry Pi! I now use my Raspberry Pi for all my media centre needs and haven’t looked back – I even have a spare SD card for using it as a portable access point for when I go travelling. Will you be doing another feature like this in the future? If so, will I be able to suggest some projects? I have a few in mind which I feel will properly make use of the Raspberry Pi. Thanks again, Phillip Cordaro

We’re glad you enjoyed the projects, Phillip. We always love to hear about Raspberry Pi projects ideas from all of our readers, even just to feature on their own in the magazine. We usually try to get at least one Raspberry Pi related tutorial or feature in the magazine every month – for example, in this issue you can find out how to turn that portable access point into a secure router with our Onion Pi tutorial starting on page 46. You can send any ideas to the email address at the top of this page.

■ Raspberry Pi projects

bring out the practical side of Linux

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Build your own Raspberry Pi robot

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ALSO INSIDE:

Make all your childhood dreams come true…

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