Linux User & DeveloperNo. 142的目錄

Your team of Linux experts… Rob Zwetsloot studied aerospace engineering, using Python to model complex simulations. Following his avant-garde yet distressing experiments with a Tux/Clippy mashup, Rob returned from his testing lab to build a Raspberry Pi video player (page 58). It’s since been stolen by the now self-aware Makeblock tank. Richard Smedley started using computers long before WYSIWYG and still maintains that the command line, and Emacs, is the most productive working environment. This month Richard discusses the rise of MOOCs and open source education (page 26), and also begins his series on writing shell scripts (page 32). Nitish Tiwari is a software developer by profession and an open source enthusiast by heart. As well as writing for leading open source magazines, he helps firms set up and use…

Jos Poortvliet tells all The KDE Project has summarised its future direction developments, with Jos Poortvliet posting a detailed breakdown to the project’s official website. According to Poortvliet, the next generation of the Plasma subsystem will include “pixel-perfect design and super smooth performance thanks to the QML and Qt 5 technologies and fully hardware-accelerated display rendering.” Poortvliet states that plans are in place for high-DPI displays and the Wayland display server, but warns that “neither are expected to be fully finished with the first release” and that it “will not be without its issue.” Poortvliet also suggests that the KDE Applications team are considering a shorter release cycle, but that “this is a discussion that needs to include the distributions as much as the upstream developers.” The KDE Frameworks project,…

The Russian Ministry of Industry has reportedly announced plans to produce an ARM-based processor, dubbed Baikal, which will be produced locally to power GNU/Linux-based computers for government and private use. According to local news outlet Kommersant Moscow, the Russian government is looking to produce 2GHz eight-core processors based on a 28nm process node and Cambridge-based ARM’s 64-bit Cortex-A57 intellectual property for local production. These Baikal processors, it is reported, would be used to run a variant of GNU/Linux tailored for the local market. The paper’s sources suggest that the reasoning behind the move is to reduce Russia’s reliance on foreign manufacturing: at present, the overwhelming majority of the government’s $800 million annual spend on server hardware goes to local companies with foreign companies like Intel getting the majority of the…

The Node.js project has announced that it is to do away with the requirement for a signed Contributor Licence Agreement (CLA), in order to encourage external contribution. Built on Chrome’s V8 JavaScript runtime, Node.js is a platform for building fast, scalable network applications. During his worldwide tour as part of the Node on the Road event series, project lead Timothy Fontaine announced changes including improved documentation and easier contribution from external parties. “The project has decided to lift the requirement of signing the CLA before contributions are eligible for integration,” Fontaine announced in a blog post. “Having to sign the CLA could at times be a stumbling block for a contribution. It could involve a long conversation with your legal department to ultimately contribute typo corrections. I’m excited to see…

I have children. My children go to school. The schools that my children go to teach ICT. To do so, they need computers. At two of those schools, there’s currently a drive to fund a bunch of iPads. Currently, said schools use a mix of desktop and laptop computers, and each has access to a bunch of interesting software tools that we parents can also get to play around with remotely in some cases. Granted, when one of my children comes home and asks if we can get a copy of said program for home it gets a bit awkward, not least when I check the prices, but there’s something useful, I think, about continuing to develop and teach keyboard and mouse skills. It seems, though, a humble computer is…

KDE KDE is an old favourite of ours and the Linux community. Slightly heavier than Cinnamon but with a similar layout and workflow, KDE is a very pretty desktop environment that isn’t hampered by any of the awkward interface problems of Unity or GNOME 3. It’s usually released a couple weeks after the Cinnamon and MATE versions. Xfce Whereas KDE is the heavier version of Linux Mint, Xfce is the lightest version of the distro. Using a layout more reminiscent of GNOME 2 – and by extension MATE as well – it’s built to take up very few resources. As with the KDE version, it’s released a little later than the normal versions. DebianEdition A very different beast to normal Linux Mint, Debian Edition, as the name suggests, is based…

The Linux Foundation offers a variety of online courses at traditional prices, including the highly-regarded “Introduction to Linux” course at $2,400. At that price it’s limited to those with generous employers, or those who really need it for career advancement. This summer it will be available for free on the edX MOOC platform. Linux Foundation’s executive director Jim Zemlin explained the motivation for this move as part of their mission “to advance Linux, and that includes ensuring we have a talent pool of Linux professionals.” There are a lot of expensive training materials in the *nix world. It will be interesting to see who follows next.…

It’s hard to compare frameworks to each other, particularly when you’re comparing three different languages and coding philosophies against each other. Python and Node.js have the advantage of being slightly longer in the tooth (although not by a great deal). Flask has the benefit of almost two decades of mostly backwards-compatible Python software development, meaning that if you come across the problem, somebody has probably already figured it out. Node.js doesn’t have the same amount of development time, but it does have a ferociously active development community; recently the number of modules on NPM outnumbered the number of Ruby Gems. That’s phenomenal. Revel/Go doesn’t have either of these qualities… yet. What it does have is backing from several of the largest software companies in the world. Go is going to…

BBC Micro It all starts in the Eighties with the BBC Micro: a computer built by Acorn for the BBC’s Computer Literacy Project, which created a generation of excellent British programmers. This included Raspberry Pi co-creator Eben Upton – the Micro was actually the inspiration for the Raspberry Pi. Acorn computers After the BBC Micros began to die out, Acorn continued to create the Acorn brand of computers using the ARM chips and RISC OS. These lasted throughout the Nineties before Acorn spun off to purely make ARM chips for mobile and embedded computers. Raspberry Pi The latest computer for schools uses an ARM processor from the remnants of Acorn computers and references the BBC Micro in its mission and naming. It’s also helping further ARM as a desktop processor…

Availability Otter is currently still in some level of development and has not made its way to repos just yet. Compiling it requires the Qt5 SDK – which is a nightmare in itself – but if you have one of the 14.04 Ubuntus you can install a binary of it, preferably in Kubuntu. Features Last time we did this we looked at the GNOME browser, which has very few actual functional features. Otter is a beta browser with a fair few more features, which all work very well and don’t reduce the browser to a crawl either. There’s also tab management, search engine management and various settings as well. Extensibility Since this is an early browser, it doesn’t actually have any extensions available right now – and whether or not…

Availability Midori is very lightweight and very open source, meaning it’s just about everywhere, either in repos or online via source and binaries. It requires few extra packages, so can be installed quickly and efficiently – it’s no wonder it’s used as the lightweight browser of many equally light distros. Features Midori’s light nature means it’s lacking in features. It has all the basic browsing stuff you’d need and some privacy tools, but there’s no syncing and it has poor tab management compared to the other browsers. This aids it in being lightweight, but it makes it less useful overall as a browser. Extensibility A selection of add-ons are available to activate from the Settings menu in Midori –although there’s nowhere near the wealth of apps that can be found…

HapPi £25 An even cheaper, education-based robot Kickstarted by The Little British Robot Company. It’s a quite simple Raspberry Pi-based robot that comes in a cardboard case that allows for a lot of customisation of the robot itself. The cardboard case allows the price to be kept down. kck.st/1nAycwf Rover 5 Seeeduino £129.99 A more than the Makeblock, the Seeeduino also uses Arduino technology but has a lot more functionality, and is slightly easier to modify when first built. It’s the big brother of the robot we featued all the way back in issue 132. bit.ly/1n73icC…

Cyanogen, the company formed by the CyanogenMod Android team, announced the hiring of three new executives. Dave Herman joins the company as vice president of product, and was formerly employed by Amazon, Microsoft and Hulu. Vik Natarajan joins as vice president of global partnerships and distribution, formerly of system-on-chip companies MediaTek and Broadcom. Tyler Carpenter joins as vice president of engineering, formerly director of engineering at HTC. Cyanogen has recently been hit by delays in shipping the One, a high-end smartphone based on the CyanogenMod port created by hardware partner OnePlus, the most recent of which related to another OpenSSL security vulnerability.…

Earlier last month, Red Hat announced the public availability of Red Hat Enterprise Linux 7, stating that it’s “redefining the enterprise operating system”. Given that this release is as much about addressing next-generation IT infrastructure requirements as it is fulfilling modern demands, Red Hat has certainly picked the right turn of phrase. Major enhancements have been made and new features added since RHEL 6, following a successful beta cycle, that paves the way for even more power, deployability and maintainability throughout enterprise IT, from application containers to cloud servers. Linux Containers have become a crucial element of open source application packaging, providing both application isolation and flexible deployment. RHEL 7 delivers on this burgeoning trend by enabling application isolation at the operating system level and fully supporting Linux Container capabilities,…

Linus Torvalds announced the final release of Linux 3.15, noting that (as reported last issue) there had been a need for an ‘RC8’ (release candidate 8) in the end, because he had been “a bit worried about some last-minute dcache fixes, but it turned out that nobody seemed to even notice those”. That wasn’t quite as true in the end. JR Okajima certainly noticed a remaining issue with the dcache, a part of the kernel that caches directory entries so that a path like ‘/dirA/dirB/fileC’ can be looked up much more quickly than walking the entire file system hierarchy starting at ‘dirA’ each time. Okajima found a theoretical trace in the dcache ‘shrinker’ code that removes entries from the dcache. He posted an example scenario that prompted Al Viro –…

We spoke to the Linux Mint team last year about making Cinnamon independent, a major step in the process: “Cinnamon is becoming an entire DE though; in 1.8 there are no visible parts of GNOME in the Cinnamon edition – everything you see is Cinnamon, including the file browser, the configuration settings, the screensaver… In 2.0 that extends to the back-end, including the session manager and settings daemon. Basically in 2.0 you won’t be running GNOME at all” It was in part way a response to Ubuntu holding back GNOME and therefore breaking Cinnamon in rolling distributions. Becoming a full-fledged desktop means this will no longer happen.…

Advisor Rob Zwetsloot models complex systems and is a web developer proficient in Python, Django and PHP. He loves to experiment with computing Resources Kdenlive www.kdenlive.org AV Linux www.bandshed.net/AVLinux.html One of the fields for which Linux is regularly overlooked is its media capabilities. Non-free codecs and questionable legalities aside, Linux works with a wide variety of popular and obscure media files and has done for a long time. This also extends to its video and audio editing capabilities, served by a selection of excellent apps for many different skill levels. Kdenlive is one of our favourites and an excellent place to jump off on. It’s easy to use yet comes with a wide variety of prosumer-level features. This month we’ll start by looking at some of the basic…

.Net aside, it’s become a little unusual to see a compiled language running a web service. This is largely due to most of the compiled languages having been conceived in a time before web development was really in swing. As such, things like easy-to-use websockets and the like are tough to implement, so we have a plethora of Node.js/Ruby Gems/ Python modules to help us along with that because they have a lower barrier to entry. Of course, the downside with these languages is that they aren’t compiled - they are fast but they still can’t quite match the performance of a compiled language. Go is the best of both worlds; it compiles so it is fast but it is also modern, so funky new things like websockets aren’t a…

Why Python ? It’s the official language of the Raspberry Pi. Read the docs at www.python.org/doc If you do even a cursory search online, you will be able to find any number of modules that will add functionality to your Raspberry Pi. Many of these are sensor modules that let you observe the world around you. What you may not know is that you probably already have a very powerful sensor module that you can use with your Raspberry Pi if you own an Xbox – the Kinect sensor. The Kinect connects through a regular USB cable, so theoretically it could be connected to your Raspberry Pi. All you need is a library to establish communication. Luckily, this is provided through the OpenKinect project (www.openkinect.org). If you use Raspbian, then…

Availability Firefox is everywhere. We’ve yet to come across a Linux distro that it wasn’t available in, although due to the recent DRM issue we wonder if it will properly be included in future Fedoras. Either way, you can grab it in whatever form you want with the greatest of ease. Features Firefox is possibly one of the most feature-full browsers in this test – although this is a bit of a double-edged sword, as it can become a little bogged down. The recent design changes have hidden some away though. Its syncing capabilities are limited compared to Chromium’s, although there are privacy concerns with that, which we’ll address later. Extensibility Firefox has the most mature and rich extension library for many reasons. Mainly, it’s due to its age and…

Olimex A20-OLinuXino-Micro-4GB €65 (around £54.35) A fully open hardware design, the A20-OLinuXino-Micro is based on the same AllWinner A20 chip as the Cubietruck, but packs in even more features with dual SD card slots, LCD connector, 160 GPIO pins across three connectors, and a noise-immune design that’s suitable for industrial use. olimex.com Raspberry Pi £28.07 Massively popular due to a large community of users and its extremely low cost, the Raspberry Pi can’t compete with the Cubietruck on features or performance but does cost considerably less, even when you account for the extras such as cables and a protective case. raspberrypi.org…

18th - 20th August The Annual Linux Kernel Summit » Sheraton Hotel Chicago, Illinois » USA » events.linuxfoundation.org An invitation-only event, the Kernel Summit is designed to facilitate discussion between kernel developers and industry leaders, and to plan the future of the Linux kernel. 20th - 22nd August LinuxCon North America » Sheraton Hotel Chicago, Illinois » USA » events.linuxfoundation.org Designed for everyone involved in the Linux ecosystem, from developers and maintainers to sysadmins and community members. Confirmed keynote speakers include edX’s Anant Agarwal, Docker’s Solomon Hykes and Jonathan Kuniholm of the Open Prosthetics Project. 23rd - 31st August DebConf ‘14 » Portland State University, Oregon » USA » debconf14.debconf.org The annual Debian developers conference, DebConf ’14 will include talks about the new ifupdown2…

Respondly, the collaborative communications platform designed to improve customer relationship management, has announced that open-source projects can now sign up for free. “In our software careers, we’ve received great benefit from open-source software and the communities that support it,” the company claimed in a statement announcing the move. “We want to give back.” Respondly provides teams with a centralised inbox and Twitter messages, and allows them to respond to queries without stepping on each other’s toes. Conversations can be shared, or ‘claimed’ by individual users who take responsibility for a given issue. A starter account on Respondly typically costs $9 per month for up to 300 conversations and monitoring of a single Twitter search, but non-commercial open-source projects can now take advantage of the service for free. Full details of…

When Tim Berners-Lee invented the World Wide Web in 1999, his proposal – presented the year before – was that “a global hypertext space be created in which any network-accessible information could be referred to by a single ‘Universal Document Identifier’” (www.w3.org/People/Berners-Lee/ShortHistory.html). The idea was beautifully simple. On the server side, there were webpages written in a hypertext markup language (HTML) that followed simple conventions and rules. On the client side, there was a browser that was able to translate the HTML code into a readable format. The web of browsable pages was knitted together by hypertext links, which became known as URLs. Berners-Lee had an unfashionable vision of “the Web’s potential to foster a global village, not its potential to earn him a villa and a fleet of cars”,…

Events like hackdays involve techies – often with non-programming domain specialists – producing useful solutions in a code sprint. LU&D has covered NHS hackdays, PyCon UK’s teacher training, and Pi- and Arduinobased activities from the open hardware community. The learning opportunity is not always the motivation for every attendant, as these events are about producing a solution to a design challenge, but everyone gains something from the experience. More directly focused on learning are the lightning talks epitomised by O’Reilly’s Ignite events: 20 slides on the screen for exactly 20 seconds each challenge the speaker to “Enlighten me but make it quick!” Unconferences, with the schedule decided by participants proposing talk titles, have also become the format for many Free Software and Open Hardware communities, with barcamps adding in late…

Advisor Tam Hanna has followed the ups and downs of the mobile market since the days of the now-legendary Palm IIIc. His firm has managed news sites, developed applications and acted as consultant. Furtherreading...  www.vogella.com/tutorialshttps://developer.android.comhttp://android-developers.blogspot.sk As mobile data started to become cheaper and faster, users began to acquaint themselves with a variety of ‘always-on’ applications. Services such as WhatsApp would not have worked in a time when mobile internet access was billed by the minute. Adding networking to your Android developer capabilities opens endless new opportunities. You can create readers for RSS feeds, communicate with remote services and fetch data from your customer’s favourite websites. Finally, you could also resort to using the network link for more sinister purposes, such as providing usage data to a tracking server in a…

Availability Chromium is slightly easier to find than Chrome on Linux, however its source code is not as accessible as most software, including Firefox. It’s also not in Fedora unless you start adding extra repos. Having said that, it’s obtainable in the vast majority of Linux distros via the repos anyway. Features Chromium is slightly minimalist but it still packs in a lot of features, from basic browsing actions to what exactly needs to be synced. There is a focus on syncing data and automatically making the web easier to browse – such as adding search fields to the omnibar – which doesn’t really slow down the overall performance. Extensibility Chromium’s add-ons aren’t actually as rich as Firefox, but it’s still got an impressive collection that is able to be…

Systems Performance: Enterprise And The Cloud Performance tuning and troubleshooting bible Author Brendan Gregg Publisher Prentice Hall ISBN 978-0133390094 Price £38.99 Score “Performance issues can originate from anywhere, including areas of the system that you know nothing about and are therefore not checking (the unknown unknowns),” says former Solaris performance engineer Gregg in his introduction. With this in mind, it’s well worth reading the final chapter, a case study, first – to get an overview of the whole process – then work your way through the book and re-read the end again, from a more knowledgable viewpoint. The first 12 chapters start with tools and methodologies for performance analysis and tuning, such as the USE method, which also gets its own appendix. Actually, USE gets separate appendices for OpenSolaris and…