Indholdsfortegnelse for Summer 2021 i Linux Format

Jonni Bidwell Come to think of it, a live music and coding session with Sonic Pi would be somewhat engaging. Viewers could submit their own code snippets via git in near real-time, and probably a chaotic cacophony would ensue, but it would make for a good experiment. Nick Peers I would stream a heartfelt plea: how do I stop buying endless amounts of optical discs for personal streaming purposes? And then follow it up with a live stream showing me going through the process of ripping, converting, tagging and adding to my ever-growing Jellyfin/Plex libraries. Les Pounder For the past year Tom’s Hardware has streamed The Pi Cast, which is a Raspberry Pi-themed show using OBS to switch between shots for a virtual webcam. We can mix live video feeds,…

“I’ve spoken to two businesses in the past month who felt that they had more Linux servers than they needed. It’s not unusual. Despite our best efforts, infrastructures don’t grow in a planned, paced fashion. We respond to events, and sometimes there isn’t time for as much thought or planning as we’d like. Planning how to change an infrastructure can appear daunting, but if you don’t do it, then the problem gets worse over time. We’re not going to be able to solve every problem in this short column, but here’s a suggestion: start with a blank sheet of paper (or better still, a whiteboard). Imagine that you’re implementing the services (not servers) that your business needs from scratch. Once you have an outline plan of the ideal infrastructure, you…

Chromebooks have been going from strength to strength recently, and in the Q1 of 2021, shipments rose a whopping 276 per cent year-on-year to 12 million units. At the beginning of 2020, Chromebook sales were around 3.2 million worldwide, but in just six months, the number has tripled to 10 million, and it now sits at an all-time high of 12 million, with HP and Lenovo making up 60 per cent of total sales. Chromebooks are incredibly popular devices thanks in part to their low price. This is because they run Google’s Chrome OS, which isn’t as resource hungry as Windows or macOS. With more modest system requirements comes cheaper hardware. Not only are Chromebooks affordable, but they’re increasingly useful, and can even run Linux applications. Their popularity grew as…

This month happens to align nicely between kernel cycles. As a consequence, since last issue Linus Torvalds has announced both the final GA release of Linux 5.13, as well as the first Release Candidate (RC1) for what will become Linux 5.14. We largely covered the 5.13 release in last month’s issue, which includes initial support for Apple M1 processor devices among its many other features. That release came just in time for the US 4 July holiday, and perhaps as a consequence the beginning of the 5.14 cycle was a little quieter. The same cannot be said of the Linux Kernel Mailing List (LKML), where there has been quite some debate lately about the latest attempt to merge support for the Rust programming language into the kernel. Proponents point to…

In its bid to take over the Linux universe, systemd has a special type of unit for timers, intended to replace the ageing, but still functioning cron. At first, creating a scheduled job using systemd seems more complicated as you need two unit files. The first is the .timer unit, which contains something like [Timer] OnCalendar=03:30 Unit=foo.service This would run the foo.service unit at 3:30am every day. The man pages show the full range of time specifications available, and there are plenty of them. You can also set timers to run a number of seconds after certain events, such as booting. The above example gives a clue as to the second unit needed: it’s the service file to be called by the timer. Timers can’t run system commands directly. It’s…

There are many ways of learning how to use a piece of software as complex as an office suite, such as tutorial videos, electronic manuals and active forums. When searching online for tutorials and other help, LibreOffice has the benefit of popularity, particularly when coupled with the materials available for its sibling OpenOffice. The website provides printable manuals that are comprehensive and well-illustrated. Because of their similarity it’s probably worth trying the OpenOffice forum if you have a question to ask. There’s also a help system built into the individual modules that’s invoked by pressing F1. The OnlyOffice website is something of a maze, and it’s easy to feel overwhelmed by the wealth of information that’s focused on the enterprise and online collaboration optional extras. Thankfully, buried within the labyrinth…

Lets start by trying desktop OBS before moving on to running it a Raspberry Pi. Largely as OBS is in the Ubuntu repositories, and probably in those of whatever distro you’re using too. But it’s always worth getting the latest version (27.0.1 at the time of writing). OBS maintain its own Ubuntu repository (the wiki covers this, as well as distro-specific instructions, at https://obsproject. com/wiki/install-instructions#linux), but since there’s a Snap package you’d be as well to use that. The Snap package includes support for hardware-assisted video encoding, virtual cameras and all sorts of other treats you probably wouldn’t get if you compiled it yourself–something Pi users will have to do as we’ll see over the page… You don’t have to be on Ubuntu to use Snaps (but if you are…

If the aim of the game is disguising your IP address, there are two different options: VPNs and the TOR network. In contrast to VPNs that are owned by a commercial company and connect through their own servers, The Onion Router network is owned by nobody and everybody connects through everybody else including the FBI! It’s free and open source, and when connecting to a server, your connection is routed through the computers of an unknown number of volunteers who are acting as relays. Each machine knows the IP address of the machine before and after it on the route, but not the originating IP. The final request to the server comes through an exit node. The big advantage of TOR is that it’s massively distributed, and therefore almost impossible…

When Raspberry Pi launched its HQ Camera in 2020 (see reviews LXF264), it introduced something very different from their previous two cameras. While the other two camera modules are made up of a sensor and its interfacing electronics together with a lens, the HQ Camera doesn’t have an integral lens. This means that you need to buy one or more lenses separately, and Raspberry Pi offers a couple of alternatives that we look at here. In that way, it’s similar to digital SLRs (D-SLRs) cameras, but different from the cameras in phones or compact standalone cameras. Our aim here is to introduce the HQ Camera for those who haven’t yet taken the plunge, and to follow this up by investigating how to use some of its less-familiar features, and at…

The HQ Camera has a blanking cap that you have to remove to attach a lens, but when there’s no lens attached, replace the cap to prevent dust contaminating the sensor. The lenses are supplied with front and rear lens caps which have to be removed when the lens in use and these should also be replaced whenever possible to guard against damage or fingerprints on the glass. Many C and CS lenses have a megapixel rating and it might sound odd that the 6mm official lens has a 3MP rating whereas the camera is 12MP. However, although optimal performance is achieved if the lens has a rating at least equal to that of the sensor, it would be wrong to believe that 12MP sensor will only provide 3MP performance…

To start, Fritzing will have all the components you’ll need in its library. In time, though, as you start to design more sophisticated circuits, you might want to use components that don’t appear in the library. In the main we’ll have to leave you to figure out the detailed process yourself, but a few words of introduction are appropriate because you might not find the approach fully intuitive. There seems to be no way of creating a new part from scratch because, unless you have a part already selected (for example, on a breadboard in the Breadboard View), the “Edit (new parts editor)” in the Parts menu is greyed out. However, the fact that it’s available when a part is selected hints at the way forward, namely basing your new…

While what we’ve done could actually be achieved using standard routing on a Linux router, the use of a firewall and routing combination allows for more fine-grained access control. For example, it makes it possible to restrict inbound or outbound traffic according to our own requirements. This can be useful. An example could be restricting inbound and outbound traffic to just HTTP/HTTPS or whatever port and protocol is required. Indeed, when we add additional networks in the next installation we can fine-tune the access between the networks. Part of the effectiveness of the whole virtual infrastructure is that it can be as simple or as complex as required. The configuration used here is wide open however, and essentially there’s no restriction between networks so anything on the test network can…

The screen can get cluttered, especially when drawing lots of images / vectors to the screen. To clear the screen type CLS. Should you need to see the running code again, type LIST to see it all, and LIST XX, replacing XX with a line number for a single line. Want to learn a little (or a lot) of BBC BASIC via your browser? Then head over to www. bbcmicrobot.com/learn/ index.html and try out its fantastic range of interactive examples. Using MOVE we can move around a screen as if our hand was hovering above a piece of paper. If we were to use DRAW then the hand would be placed on the paper, pen in hand and ready to make a mark on the screen.…

Docusaurus is an open source documentation application developed by Facebook. It’s one of a growing number of JAMstack static site generators that uses a blend of JavaScript, React and markdown to make it easy for you to deploy clean, professional-looking documentation sites that are easy to maintain. A Docusaurus site can be managed as a git repository, meaning that version control is baked in and, perhaps most importantly, your developers can use their tool of choice to directly edit the content in markdown files, or even edit the files directly on GitHub. Although Docusaurus v2 is technically still in beta, they recommend using it, even in production. The objective of this tutorial is to deploy a customised documentation site to the cloud using GitHub and a free Netlify account. Netlify,…

VECTOR IMAGE EDITOR Inkscape Version: 1.1 Web: https://inkscape.org There’s only one vector editor for Linux that can compete with commercial packages such as Corel Draw or Adobe Illustrator. Indeed, Inkscape is one of the jewels in the crown of open source software. The program is packed with a rich set of features, and it’s become a versatile application for many creative activities including digital art, illustration, icon design, business graphics, plans and more. It can also be used for graphic design, such as creating a poster or brochure. Inkscape often comes top when pitted (see Roundup LXF248) against other vector-editing solutions for Linux, including Karbon (part of KDE’s Calligra Suite) and LibreOffice Draw. Now we have a fresh version that’s packed with new features. The appearance of Inkscape 1.1 back…

Pylint – a comprehensive linter that focuses on standards compliance and error detection. It’s likely built into your favourite IDE. Pycodestyle (formerly known as PEP8) – focuses on validating code formatting PEPs, has some overlap with Pylint. Pyflakes – focuses on quickly detecting errors without raising false positives, has some overlap with Pylint. McCabe – a cyclomatic complexity analyser counts the potential branches in a function to give an indication of code complexity. Dodgy – a Linter specialising in detecting hard-coded secrets, or accidentally leaked credentials. Pydocstyle (formerly known as PEP257) – a linter focusing on docstring style and structure. Mypy – static-typing validation for Python. Frosted – this is a fork of Pyflakes that used to better maintained, but has unfortunately not been updated in several years. Pyroma –a…

Pandas can perform a variety of tasks including data loading, preparation and manipulation as well as data modelling and analysis. You can join, merge and reshape data with the help of Pandas, using data from different sources. As mentioned elsewhere in this tutorial, everything begins with a structure and the data you add to that structure. The two data structures supported by Pandas are data frames (pandas.DataFrame) and series (pandas. Series). You usually put data in these two data structures by reading it from a file. Apart from reading data from CSV files, Pandas can handle a wide range of data formats including HTML, JSON, Microsoft Excel, SPSS, SAS and Google BigQuery. Additionally, Pandas can save data into various formats including CSV, JSON, HTML, SQL and Microsoft Excel. Even though…

USING THE LXFDVD Using Linux for the first time can be very confusing. It’ll most likely be unlike anything that you’ve operated before, especially if you’re used to Microsoft Windows or Apple macOS. Generally our DVDs are designed to be run directly, which is to say that when you first power on your PC (or Mac, see below) it should ‘boot’ from the DVD – so before Windows or macOS even starts to load – with Linux running directly from the DVD. This trick is known as a Live Disc. It enables you to try out the various versions of Linux without having to install or change anything on your PC. Just remove the DVD, restart your PC and it’ll be exactly as you left it. While many systems will…

Live streaming isn’t a subject we touch upon much, which is bad when the world’s leading streaming software is open source under the GPL v2. That’ll be the Open Broadcaster Software aka OBS Studio and it started life as one man’s open source project. These days it’s sponsored by YouTube (owned by Google), Twitch (owned by Amazon) and a social networking site that we won’t mention. Of course, being open source means that you can apply it to almost any application you like. From streaming your Linux desktop to a Twitch channel, to compiling it for the Raspberry Pi and broadcasting your avian-based birdbox activity to a self-hosted open hosting platform. It’s down to you just how much in control you want to be. If you like to keep things…

The fallout from the Red Hat’s decision to announce the end-of-life of CentOS 8 and replace it with CentOS Stream (see LXF278) rumbles on. While the CentOS alternative Rocky Linux, led by CentOS co-founder Greg Kurtzer, has hit 80,000 downloads (as reported by The Register at https://bit.ly/LXF279Register), AlmaLinux remains keen to win over ex-CentOS users who may be uncomfortable with Kurtzer’s control over Rocky Linux. AlmaLinux claims it’s the only “CentOS alternative that is 100 per cent community owned and governed.” The AlmaLinux Foundation has been set up, and AlmaLinux OS 8.4 for ARM64 has been released (download it from https://bit.ly/LXF279AlmaLinux) with features such as Secure Boot support and Python 3.9 module streams. While Rocky Linux hasn’t been bashful about announcing its success, assessing AlmaLinux’s popularity is more tricky. An…

“Life these days is busy, and I seldom get to do hands-on kernel development at any scale. When I do get to poke at kernel internals, it’s usually because something has gone very wrong. I enjoy such debugging. If you’re lucky, the affected machine provides a nice backtrace (a kernel log message showing the exact line of code where a “panic” – crash – occurred). The kernel these days is very good at providing useful information, when it can do so. And there are excellent tools (such as lockdep, and KASAN) that will enable you to build a kernel that will aggressively monitor itself (at a cost to performance, which is why these features are seldom enabled in production kernel builds). But sometimes, there isn’t much in the way of…

We’d love to try and answer any questions you send to lxf.answers@futurenet.com, no matter what the level. We’ve all been stuck before, so don’t be shy. However, we’re only human (although many suspect Jonni is a robot), so it’s important that you include as much information as you can. If something works on one distro but not another, then tell us. If you get an error message, please tell us the exact message and precisely what you did to invoke it. If you have, or suspect, a hardware problem, let us know about the hardware. Consider installing hardinfo or lshw. These programs list the hardware on your machine, so send us their output. If you’re unwilling, or unable, to install these, run the following commands in a root terminal and…

Office applications have seen many improvements since the first spreadsheet and word processing programs were made available for personal computers. However, what you do with the programs that handle the core office activities hasn’t changed a great deal. These activities include creating text documents, using a spreadsheet or a database and putting together graphs and presentation data. Note that two of the suites – WPS Office and FreeOffice – have picked up an annoying habit from Microsoft of naming the current release after a given year and then not incrementing it in subsequent years. So, we’re looking at the latest versions of all of the suites (they were updated in 2021) even though they are entitled WPS Office 2019 and FreeOffice 2018. Office suites span two extremes of integration: some…

All of the office suites featured in this month’s Roundup are usable on a reasonably modern computer. However, we did encounter differences in overall responsiveness, and this was particularly apparent in our ‘old laptop’ test. As expected, LibreOffice and Calligra ran at the speed of typical, native applications. OnlyOffice is actually a JavaScript application, and when you run it locally, it’s running inside a sort of container. It should be fine on modern systems, for day-to-day use, but it was unusably laggy on the slow old laptop. FreeOffice was in the same boat: text input lagged on the laptop. Even on a more modern desktop computer, there was always a feeling that those two suites weren’t lightning fast and suffered from a bit of lag, but it wasn’t bad enough…

There’s a nonzero chance that routers supplied by your ISP won’t support direct connection to a VPN. Some providers supply preconfigured routers that will make setup very easy. Any query that you can search online about VPNs – their effectiveness, uses, features, or even ‘Do I need a VPN to watch Luxembourg TV’ – has been gamed to death by highly paid SEO specialists. Look for advice on the r/privacy subreddit instead. Using a VPN will slow down your connection. If you don’t need to be connected to a VPN for your current activity, you should probably turn it off. Opera’s built-in VPN isn’t a true VPN, but it will help enable you to view geoblocked content. We wouldn’t trust it with any sensitive data, though.…

The focal length is proportional to the magnification provided by the lens and is inversely proportional to its field of view. However, direct comparisons can’t be made between different lenses if they’re used in conjunction with differently sized sensors. For that reason, a 35mm equivalent focal length is commonly quoted because it’s familiar to photographers and provides an easy way of making comparisons. The 35mm equivalent focal length is calculated by multiplying the focal length by something called the crop factor, which depends on the sensor size. For the HQ Camera this about 5.5. This means that the 35mm equivalent focal lengths of the 6mm and 16mm lenses are 36mm and 88mm, respectively. A lens with a 35mm equivalent focal length of 50mm is considered to be a “standard lens”,…

The component symbols in the schematic view are of the American type, for example, a zig-zag line for a resistor instead of the rectangle as used in Europe and most other places. If this is a problem, you could create new versions of the affected components which differ only in their symbols. You can generate a list of components at File>Export> List of parts (Bill of Materials). The list is in two parts. First is an assembly list that provides a description for each part. And second there’s a shopping list that aggregates parts so you are shown how many of each component you need to buy. There’s an autoroute option in the Schematic and PCB Views. This will attempt to turn rat’s nest lines into routed connections, but you…

It’s often said that a clever person solves a problem, but a wise person avoids it. So it is with repairing computers. It’s all very satisfying fixing things, but it would be better if they didn’t break in the first place. That’s slightly unrealistic thinking, but if you have up-to-date backups of your important data, then it will take the pressure off if the worst happens. We did a backup special a while back (see LXF267) and discovered that it’s easy to set Déjà Dup up once and then have it perform automated backups. For less regimented backups, for example the overdue manuscripts you’ve been working on this week, saving to any kind of cloud storage service (or better still, your own Nextcloud instance) will give you ample redundancy. Lots…

In addition to the s-tui.conf file, the ~/.config/s-tui directory also contain a directory called hooks-d. You can place custom scripts you wish to execute when a certain threshold, such as CPU temperature or frequency is exceeded, within this directory. The name of the script must be <name>source.sh, where <name> is the name of the supported source. While you can use S-TUI to track various sources, for now it only supports running scripts based on CPU temperature threshold setting. The default threshold value for the CPU temperature is 80. To change this value, you must invoke S-TUI with the s-tui --t_thresh <value> command. You can then save the new threshold value into the ~/.config/s-tui/s-tui.conf file by saving the settings from within S-TUI itself. If you make any changes to the settings…

While you can edit individual images opened from within an Office document, you can’t save any changes. Instead, you need to right-click the amended image and choose Copy, then open a new tab (Ctrl+T) and press Ctrl+V to paste it as a new image. The nomacs website (https:// nomacs.org) is packed with useful information. Select Documentation> Tutorials to learn how to use many of its features with the help of detailed instructions and example screenshots. Speed up navigating through large groups of photos in a folder by using the Page Up and Page Down keys to skip 10 photos at a time. You can adjust the number of photos skipped via Edit> Settings>File.…

There are times when you’ll want to compare two images – side-by-side, or maybe even by layering one on top of another and changing the opacity of one so the other can be viewed beneath it. At times like these, being able to synchronise certain features – namely panning and zooming – can prove extremely useful. Thanks to nomacs’ synchronisation tools, not only can you do this using two (or more) instances of nomacs on one PC, but you can also set up sync across two different computers on the same network. If using a single PC, open your image in nomacs and then choose File>Start New Instance. A duplicate instance of nomacs will open, complete with the current image loaded. Now, open Sync> Synchronize on either instance where you…

For those people who work on team-based projects, it’s hard to imagine daily computing tasks that don’t use sync and share platforms or services. Dealing with document processing will also be high on the agenda. Combining these two elements certainly makes sense to us! It’ll come as no surprise that users prefer to work with documents within their environment, without having to involve third-party tools. With OnlyOffice Docs, you can easily implement this scenario. OnlyOffice Docs is an open-source web-based office suite that provides you with online editors for text documents, spreadsheets and presentations. The suite is compatible with OOXML formats (.docx, .xlsx, .pptx) and contains a wide range of editing, formatting and styling tools along with collaborative features. OnlyOffice Docs can be seamlessly connected with multiple sync and share…

During the research for this feature we learnt about BBC Micro Bot. No, not the microcontroller but rather a means to write BBC BASIC code in a tweet. We simply send a BBC BASIC code sample to@bbcmicrobot. It runs the code in an eight-bit emulator and then sends the output back to you as a tweet. At the time of writing this project has generated over 10,000 tweets and run over 18 trillion cycles on the virtual 6502. The output from these tweets can be a simple hello world or it can be an elaborate animation. Looking through the examples we can see the Ingenuity, the helicopter which flew around Mars from the Perseverance rover, many mandelbrot animations and a particularly effective tunnel which would look right at home running…

While you might need to set these CI/CD jobs to allow failures, for now, this new visibility of the issues in the code-base is ultimately going to have the desired effect of being granted time to work on technical debt. A bad project manager will gladly ignore problems that aren’t visible, and may even treat the people who voice concern with disdain. Even a bad project manager, however, can’t ignore visible evidence of security flaws, and this can save your job if there’s a security breach because you’d be able to prove that it was due to their negligence in not prioritising the security risks that you’ve been raising to them. It’s important to remember the majority of project managers aren’t bad, but simply lack the input to correctly weigh…

NumPy (https://numpy.org) is the primary Python package for performing scientific computing. NumPy brings two main things to Python: NDArray, which is a multi-dimensional array object and Universal Functions, which are very fast math operations between array objects. Although arrays aren’t everyday objects, they’re extensively used in mathematics and in the computer graphics areas – all NumPy array objects are of the numpy.ndarray data type. SciPy (www.scipy.org) is built on top of NumPy and is more advanced than NumPy. SciPy supports numerical integration, optimisations, signal processing, image and audio processing and statistics. Finally, Matplotlib (https://matplotlib.org) is a Python library for creating static, animated and interactive visualisations in Python. Matplotlib can generate really impressive plots! Although both NumPy and SciPy are better at data processing, Pandas is better at data manipulation. Always…

THE LXF LIBRARY Advanced Bash Scripting Guide Go further with shell scripting. Bash Guide for Beginners Get to grips with the basics of Bash scripting. Bourne Shell Scripting First steps in shell scripting. The Cathedral and the Bazaar Eric S. Raymond’s classic text explains the advantages of open development. The Debian Book Essential guide for sysadmins. Dive Into Python Everything you need to know. Introduction to Linux A handy guide full of pointers for new Linux users. Linux Dictionary The A-Z of everything to do with Linux. Linux Kernel in a Nutshell An introduction to the kernel written by master hacker Greg Kroah-Hartman. The Linux System Administrator’s Guide Take control of your system. Tools Summary Overview of GNU tools. GNU Emacs Manual Six hundred pages of essential information! Producing Open…

“For the past few months I’ve been working on improving the experimental Wayland driver for Wine, which enables Windows programs to run on Wayland compositors. The latest update adds several features including Vulkan support, multi-monitor support and HiDPI handling, cursor clipping/ relative movement, and Wayland keymap handling. In addition to multi-monitor support, the driver also supports changing the application-perceived resolution of each monitor to implement mode changes. There’s also support for HiDPI monitors, which is achievable under the current Wine and Wayland constraints. Cursor clipping and relative mouse movement is an important feature for FPS games, and the driver uses heuristics to map application requests to Wayland functionality. The driver now has enough features to be useful for many cases, while also providing enough confidence that it’s a viable option…

“I saw a post on Twitter asking about companies that approach open source “the right way.” This got me thinking ... is there a right way? To start with, do you value things being fully open, with a side order of easy? Or do you want things as easy as possible, and open as an afterthought? Do you want code to be open for users to deploy as they want, or do you want to put restrictions on certain users? For those companies that want to build a large, diverse community of contributors, doing open source “the right way” involves transparency, developing in the open and collaborating closely with that community. The entire development process should focus on partnership, from processing pull requests, answering bug reports in a timely manner,…

Stop the silence  Q I’m running Mint 20.1 Ulyssa Cinnamon. I use the built-in network management tools to connect to a VPN running OpenVPN. I used to get a notification on the top right-hand corner confirming a successful connection when I started it, but I accidentally hit the “Don’t show this again” button one day. Despite searching I cannot find out how to reverse this. It was very useful. Ian Gibbs A  It’s not obvious, but you need to edit the dconf database that is used to store Gnome settings. You can do this from the command line with the gsettings tool. Run one or more of these commands as your normal user, not with sudo: $ gsettings set org.gnome.nm-applet disable-vpn-notifications “false” $ gsettings set org.gnome.nm-applet disable-connected-notifications “false” $ gsettings set…

The text for this month’s Roundup was created by continually moving it between the word processor modules of the various office suites. We also loaded various test files, in the standard formats that you’re likely to encounter, into as many of the modules as we could, making notes of the speed and accuracy of this process along the way. As well as using a desktop PC, we also ran the suites on a rather outdated laptop, an old eMachines model with 2GB of RAM, a 1.7GHz CPU and a 1,024x600 display. This is to test to see if the suite could be used to bring an older machine back to life for light office duties – a valid application for an office suite. We also spent some time on the…

Beyond its file-sharing facilities, Google Drive offers an online office suite with a word processor and a spreadsheet, among other things. It’s useful for collaboration work and document sharing and it handles backups and revisions automatically. The word processor is fine and capable of spotting grammar errors. The downside is that the interface is a bit laggy. The fabled GNOME Office is also worth looking at, but it’s debatable whether it still exists. What we mean by that is that it’s a rough collection of applications such as AbiWord and Gnumeric that can be installed in one go. The applications themselves are very nice, if a bit old-fashioned in function. The problem is that the concept seems to have been abandoned, and although the applications are still maintained, mainstream distributions…

While we were planning this feature, a little voice at the back of our head muttered, “Can we get a Raspberry Pi angle in?”. It turned out that voice was actually that of our group editor (that’s Group Editor in Chief, Tech to you – Ed), and we like to keep him happy. So we’ve come up with a couple of ways to quieten his screams for Raspberry Pi streams. We’re always looking for new Pi camera projects, so first we reached for our trusty Pi Zero and attached the camera that we used for our motion detection tutorial back in LXF266. Remember that if you’re setting up a headless Pi from scratch, the SSH service is disabled by default. If you’re running wirelessly you’ll need to tell it about…

Budding disc jockeys, mix masters, selektas and soundpeople may be tempted by the self-hosting option because it obviates the problem of automated DMCA takedowns that plague other platforms. Many a Twitch streamer has found their streams muted or stopped altogether because they had something that sounded like copyrighted music playing in the background. There are fair use exceptions to these things and copyright strikes can be contested, but the hope of being vindicated in a couple of days is little recompense for your broadcast being shut down. We’re not lawyers, but if you host a stream and only tell people you know about it (and certainly if it’s password protected) then that seems pretty much like an extension of your front room and you’d expect to be able to play…

So you’ve decided that you do need a VPN in your life after all. The next thing to think about is whether or not it suits your needs. Sure, everything on the front page of Google will promise (and probably deliver) great speed, easy-to-use tools and fantastic support. You also need to consider how many devices are allowed. Can you only get Gardeners’ World on a handful of devices, or does the service permit unlimited connections? If so, check the T&Cs to find out if unlimited is actually unlimited or mere sales words to fool the unwary. Linux support is a must, and if at all possible, you want a VPN service that keeps its help desk in-house rather than outsourcing to a hack-prone third-party liability. Lastly, if you want…

The first Raspberry Pi we had (the original model B) was used to connect an old printer to the network for use as, unsurprisingly, a networked printer. We then ended up with many more, from being used as small headless servers to projects such as a photo booth for my brother’s wedding. A Raspberry Pi 4 was my son’s first computer at age five, and he’s had hours of fun playing GCompris and Minetest on it. Raspberry Pis have also proven invaluable for use in schools. I run a Code Club at the local primary school and the ability to have a ready-made class set of SD cards makes it so much easier to organise. There’s also the welcome knowledge that at the end of a session any data left…

We have the bare electronics for the robot, but lack a chassis. Fear not! We can go down two routes: a kit or a DIY option. By far the easiest way is to use a kit. These kits can be found on eBay and Amazon for around £10 and they provide the motors, wheels, battery pack and laser-cut acrylic chassis along with all the fixings. These kits are a bit like Ikea furniture, and without too much work we can have a chassis ready for our Raspberry Pi. Look for a kit that comes with pre-soldered motors, it saves a lot of time. But if you can solder, and have the kit, no problem. The DIY option is more adventurous. If you have access to a laser cutter or 3D…

It’s easier to remember something if you understand the principles, rather than just learning by rote. Because f-stops, which are the measure of aperture, aren’t immediately understandable, here’s what you need to know. The way f-stops are written might seem strange. However, it’s really very simple. An aperture of f/4 means that the diameter of the lens – as reduced by the iris shutter – is the focal length divided by 4. So, in the case of the HQ Camera’s 16mm lens, at f/4 the iris shutter will have a diameter of 4mm. This, of course, explains the apparently contradictory fact that a large f-stop number implies a small aperture and vice versa. Because the amount of light a lens can admit depends on its area, and the area is…

1 Boot Rescuezilla If you don’t have this month’s DVD (or a machine with an optical drive) to hand, download Rescuezilla from rescuezilla.org and write it to a USB stick with Etcher (https://etcher.io). Then boot your medium (see the DVD pages if you’re new to booting from external sources) and await the friendly Rescuezilla menu. 2 Back up a partition Choose the back-up option and select the drive and partition you want to back up. You can back up to local storage or remotely over SSH, NFS or Samba. Remember that Rescuezilla images don’t get compressed, so if your network is slow and your partitions large then this process will take some time. Best get a cuppa. 3 Restore a partition If the worst should happen to that partition, and…

Are you looking for a good tool to view – and perhaps edit – your images easily? While Shotwell might seem like an obvious choice, it’s more geared towards building a library of images rather than acting as a quick-and-easy image viewer. What you need is nomacs. The tool bills itself as an “image viewer”, but that does it a major disservice. It’s an excellent choice for viewing single files, or the contents of folders, supporting a wide range of image formats (including Photoshop PSD and RAW image files from digital cameras), but it does so much more. You can edit a photo’s metadata for example, and correct problems with photos courtesy of nomacs’ Adjustments menu. It even throws in a few clever effects, including photo mosaic and tiny planet…

In the early 1980s there were many different dialects of the BASIC language. Commodore had used a form of Microsoft BASIC for their machines, but for the BBC Micro, Acorn reused their Atom BASIC, with a few extensions to take advantage of the hardware. BBC BASIC was created using code written by Sophie Wilson and colleagues and was released in 1981. BBC BASIC was the default means to interact with the hardware for the BBC Micro and the Acorn Electron. BBC BASIC was highly optimised and as a result it ran extremely fast compared to Microsoft BASIC. BBC BASIC was learnt from the included user guide, and that book became the go to reference for many budding developers. From that book we could take our first steps to create simple…

If you want to use Docusaurus for a real project then there are several avenues that we recommend exploring further. The Docusaurus site (https://docusaurus.io) should be your first port of call. There’s a lot of useful information on its site and you can find out more about creating, formatting and navigating pages. There’s also insights on the various configuration options in docusaurus.config.js and how to extend Docusaurus using plugins. Because Docusaurus is based on React you can also learn about creating and importing components that can then be reused throughout the site. This is useful when you don’t want to duplicate content, but need it to be available in multiple places. On the Netlify front you can also edit the random URL your site is assigned to something that’s more…

THE SWORD OF ZORIN MIN SPECS: 700MHZ CPU, 512MB RAM, 8GB DISK Zorin OS Lite Yes, we know. Zorin OS 16 will probably be out by the time you’re reading this. Rest assured that it wasn’t at the time we compiled this month’s DVD, and we didn’t really feel comfortable putting the beta version on the disc. Anyway, going with this edition enables us to serve up a rare treat to users of 32-bit machinery – machines that can’t run all the glorious distros based on Ubuntu 20.04 and later. Zorin OS 15 is based on Ubuntu 18.04, so is supported until 2023. We haven’t featured Zorin OS for some time, but it’s a fine distro that’s well worth checking out. It bills itself as something that will “make your…

Classic distro hopping Emulating old PCs is fun and enables us to explore those classic distros of old. We travel back in time to the days of the floppy! Terminal browsers We couldn’t think of anything more appropriate than testing web browsers that you can run in your terminal. Design documents in Scribus Get to grips with one of the longer-running creative open source projects and put together professional-looking pamphlets. Nextcloud on the Pi We get right up to date with the latest release of NextCloud and deploy it on everyone’s favourite tiny computer. Contents of future issues subject to change – as we might never come back from summer holibobs. LXF280 will be on sale Tuesday 24 August 2021…