Linux Format的February 2020目录

“I had a nice mail from one of our clients this week. She said, “I cannot thank the team at Tiger enough for the support and peace of mind you have given to me in the past three years; it truly has been a pleasure working with you.” Of course that’s a nice email to receive, but it’s also interesting. Her perception is that we gave her support and peace of mind. The first is what we do. The second is what she gets. There are some IT workers who fill their working lives with panic, impending disaster, rush rush rush. And there are some managers who think they aren’t getting value for money unless their IT workers behave like that. Let’s leave these ones in “peace” together. The alternative…

Linus Torvalds announced the release of Linux 5.5-rc1 and the closure of the “merge window” for Linux 5.5. The new kernel gains several features, both user/ programmer visible and internal to the kernel. On the visible front, a few legacy interfaces have been deprecated or removed (iopl() through emulation, and sysctl() by removal). Meanwhile, internal changes include the wholesale replacement of the scheduler load balancer, which could end up being very visible to users if it impacts performance. Privileged I/O Levels The x86 architecture has been around for over 40 years. In that time, many trends have come and gone, but the need to retain backwards compatibility means that various gunk has stuck around. One of the antiquated concepts that survives to this day the I/O port. In 1978 it…

Comparing directories Q I have two folders that are backups from different months of the same Linux: LinuxA and LinuxB. I want to know what was modified in LinuxB compared to LinuxA. I have heard about the diff command, but reading the diff manual doesn’t seem right: “GNU diff – compare files line by line” The comparison I believe I need is to compare the files by date modified and if different, that file has certainly changed. Do you have any idea how I can do this? Nick A Modification dates do not provide a reliable guide as to whether a file has changed. Consider a program that loads it settings when it starts and saves them on exit. The configuration file’s timestamp will change but the contents will be…

Back in July 2019, AMD launched a massive 7nm offensive on the CPU world. What can it do for an encore? More cores, more threads, and potentially higher clock speeds. The Ryzen 9 3950X really impresses in some areas, though it’s not quite as awesome in other respects. Let’s start with the best use case, which is anything in the content-creation realm. With 33 per cent more cores than the 3900X and similar clock speeds, it’s usually 25-30 per cent faster. If you do video editing, 3D rendering or any other task that can benefit from a 32-thread processor, you’ll love the 3950X. For tasks that don’t scale well to 16 cores, though, you’re better off with a less expensive part. Even though the 3950X is nominally a consumer CPU,…

Despite now being a KDE project, Falkon is still found lacking in this department. This is because it ships with just eight extensions out of the box, but they are all quite useful. You can access them from the Extensions tab on the Settings window. Apart from Adblock, the browser boasts a mouse gestures extension, this lets you navigate through webpages using gestures. There’s a reverse image search extension. Also on offer are two extensions dedicated to how the browser handles tabs. As the project gains popularity, more themes and extension will become available on the http://store.falkon.org website, which is currently home to just a handful (just thirteen) of extensions, with incomplete instructions on installation or the functionality they provide. Add-ons for Pale Moon are split across different categories. As…

Greg Kroah-Hartman is a man who needs no introduction. Sadly intros are strictly required by our interview template, so here goes: he has been described as the gentle giant of the Linux kernel. He’s custodian of the USB, PCI hotplug, Userspace I/O and debugfs kernel subsystems (not an exhaustive list), and he sits on the Linux Foundation’s Technical Advisory Board. He’s even featured in Linux Format before, in 2006 (LXF81, back when we had budgets exceeding a pittance). Jonni Bidwell was understandably starstruck and giddy when the towering figure agreed to talk drivers, desktop Linux and other diversions in a dimly lit meeting room in the Centre de Congrès de Lyon, while outside excited attendees mingled with open source luminaries at the Linux Foundation’s 2019 Open Source Summit. Linux Format:…

Whatever backup system you decide to employ, you will most likely need to encrypt your backups. Backups contain sensitive information, such as passwords and SSH keys, often in files that can only be read by the root user. But if your external hard drive is stolen, the thief can access all that information as the root user. Encryption also makes sense if you’re using a cloud or off-site service. You may not absolutely need it if you are backing up to a local NAS that is physically secure and not accessible from the internet, but why take a chance? Most backup software has an option to encrypt the backups, and if you are using an rsync-based method, you can encrypt the drive or folder used to store the backups.…

This a list with a good selection of backup software to try. It is far from exhaustive, but these are all established programs that approach the task of backing up in different ways. Amanda ...............................http://www.amanda.org Back In Time ...................https://backintime.readthedocs.io BackupPC..........................https://backuppc.github.io/backuppc Bacula...................................https://www.bacula.org Borg Backup....................https://borgbackup.readthedocs.io BorgWeb .............................https://pypi.org/project/borgweb Burp........................................https://burp.grke.org DAR.........................................http://dar.linux.free.fr Déjà Dup Backups ......https://gitlab.gnome.org/World/deja-dup Dirvish ..................................http://www.dirvish.org Duplicity..............................http://www.nongnu.org/duplicity luckyBackup....................http://luckybackup.sourceforge.net rdiff-backup .....................https://github.com/rdiff-backup/rdiff-backup rsnapshot...........................http://www.rsnapshot.org Simple Backup ..............https://sourceforge.net/projects/sbackup Snapper...............................http://snapper.io ZBackup: ............................http://zbackup.org…

In 2016 Western Digital briefly boarded the Raspberry Pi train with its PiDrive, a range of hard disk drives and cases. While the cases covered every purpose from media centre to home server, the real magic of this setup was the inclusion of a pre-installed microSD card running either NOOBs or BerryBoot. Some kits were simply a HDD (250GB, 314GB, or 375GB) and data/power cable, while others included a Raspberry Pi 3, case, cables and even a keyboard alongside the HDD. Regardless of whether the PiDrive shipped with BerryBoot or NOOBS (as in the WD PiDrive Foundation Edition), it’s optimised to run multiple operating systems. Connecting a Raspberry Pi 3 with a PiDrive of considerable capacity can deliver a system capable of handling multiple scenarios. It might run Raspbian, with…

Many Linux programs, be they distributions or applications, still use IRC as a means of connecting with the user community. You’ll often find many developers on these IRC channels and there’s a good amount of help and information to be found if you can make your way to IRC. The Irssi application is quite popular and you’ll find it in the software repositories of most modern desktop distributions. When you run Irssi for the first time, the tool will use the settings from your current user account to populate its config file. Your username will be your nickname, and your full name will be used as the real name. During chat session on IRC channels, the nickname is used to identify individual users. You can define a custom nickname with…

One of Booksonic’s strengths is its support for multiple users, allowing family or friends to have their own customised access to your server. Do so via the Users tab under Settings: you’ll see that by default new users can change personal settings and their password, as well as play files, but we’d recommend allowing them to also download files to listen to offline. You’ll notice that Booksonic allows you to add multiple media folders to its library: this enables you to organise your collection by genre or set up multiple folders for a multi-user setup. That way you can restrict access on a per-user basis to specific parts of your (Mills & Boon collection?–Ed) library. Simply provide a suitable name, enter the path manually (for example /home/username/audiobooks/ mrspeers) and click…

Having a Kali Linux NetHunter phone of its own can be fun, but where it really comes into its element is when you pair it with a BadUSB. Get yourself a premade unit, or build a P4wnP1 out of a Raspberry Pi Zero W. Pop the small unit into a target’s machine and walk away, then use the NetHunter phone to remote-access into the local Wi-Fi access point via SSH, and you’ve essentially got full access to a target’s machine, while still in line of sight. At this point you can initiate behind-the-scenes reconnaissance, or launch a RubberDucky (see LXF226) prank and enjoy the reaction in real time, bringing a whole other dimension to hacking. Wait until your target gets back to their PC, then launch Rick Astley’s Never Gonna…

We’ve simulated elements of a simple microprocessor as a means of learning how they work, but CPUs are also simulated for historical purposes. Take, for example, the SSEM, known as the Manchester Baby, which was the world’s first stored program computer and ran its first program at Manchester University on 21 June 1948. Although the original hardware didn’t survive, a working replica was built to celebrate its 50th anniversary, and is now on show at the Science and Industry Museum in Manchester. While this is occasionally exercised by running software, it’s not readily available for most people to use, and this is where simulation comes in. A web search will reveal at least a couple of Manchester Baby simulators, but the one we’d recommend, should you fancy learning about the…

Grafana comes with a command line tool named grafana-cli that allows you to perform admin tasks, including the installation of plugins and the resetting of the admin password. Fortunately, the Grafana Docker image contains grafana-cli, which means you can execute it without having to install it on your own. Learn the version of grafana-cli installed on the container with: The grafana-cli plugins list-remote command lists all available plugins, whereas grafana-cli plugins ls lists all installed plugins. You can remove a plugin with the grafana-cli plugins remove <plugin-id> command, you can install a new plugin with the grafana-cli plugins install <plugin-id> command, and you can update all installed plugins with the grafana-cli plugins update-all command. Note that you can find the list of available Grafana plugins at https://grafana.com/grafana/plugins, where you can…

It’s 2020 and there’s no doubt that this is the year of Linux on the desktop. That’s the running joke among the Linux community, but the truth hiding behind it, is that there are millions of happy desktop Linux users out there in the world and this is your chance to join them. If you’d told many people ten years ago Linux would be getting same-day driver support from manufacturers, you could game with Steam and play AAA titles natively on Linux, run a full office suite that is used by governments, render with software used by the largest game and film companies, that it was going to run the majority of mobile phones, and that a best-selling home computer (that’s the Pi) used it, they’d think you were mad.…

The CDU, Germany’s ruling party, has passed a resolution to demand that software developed with public money will also be made publicly available as free software. As the Free Software Foundation Europe (FSFE) notes in a press release (which can be read at http://bit.ly/LXF259FSFE),this move aligns with the FSFE’s “Public Money, Public Code!” campaign, which is supported by over 170 organisations and 26,000 individuals. The CDU’s convention resolution (find it her: http://bit.ly/LXF259CDU) declares that, “It is only through openness that competition can be created; only through openness can new players in competition challenge the top dogs,” and that all future public… projects in Germany will “be subject to compliance with the principles of open source and open standards.” Matthias Kirschner, president of FSFE, welcomed the move: “We are pleased that…

“I recently swung by the second annual RISC-V Summit in San Jose, California. At the conference were gathered hundreds of developers who are vigorously engaged in making RISC-V the next big thing. They’re building an open source architecture unencumbered by licensing fees or even geographical restrictions, but beyond that they’re having a lot of fun in the process. Hanging out with these folks feels like the early days of being involved in Linux, back when everything was new and the world was just starting to be put together. In many ways, watching the RISC-V community also feels like watching the early days of Arm, modulo and a lot of the learnings having been taken on board – though not all of them (there’s still a giant hole where various platform…

Build Brighton Thursday evening is open night. http://buildbrighton.com Cornwall Tech Jam Second Saturday of the month, alternating between Bodmin and Camborne. www.cornwalltechjam.uk Thingqbator An IoT-focused makerspace, meeting weekly at The Shed MMU. mcr.thingqbator.org Leeds Hackspace Open night every Tuesday 7pm-late. Open day second Saturday of the month, 11am-4pm. http://leedshackspace.org.uk Huddersfield Raspberry Jam Meet every month at Huddersfield Library, typically the fourth Saturday of each month. http://huddersfieldraspberryjam.co.uk rLab Reading Hackspace Unit C1, Weldale St, Reading, open sessions Wednesday from 7pm. http://rlab.org.uk Horsham Raspberry Jam Park Side, Chart Way, Horsham. www.facebook.com/hackhorsham Medway Makers Meet every 3-4 weeks on a Sunday. Full details at: http://meetup.com/Medway-Makers Maidstone Hackspace We hold open evenings every Wednesday from 5.30pm-8pm. https://maidstone-hackspace.org.uk Glasgow Makers and Hardware Hackers Mitchell Library, Glasgow. www.facebook.com/groups/115303729096198…

A file link is a way of having the same file (or directory) appear in two or more places, or under different names. You could copy the file to each location, but this wastes space, and if the original file is updated, the copy is the old version. Linux filesystems have a means of accessing the same file or directory from a number of places – links. There are two types of link; hard links and symbolic links, often called symlinks. Technically, every file is a hard link, as this is a link from the file’s name to the data structure on the disk that holds its contents. When referring to hard links, we mean extra links, so that a file has more than one name. Hard links have limitations…

Send your thoughts to the Linux Format dungeon server at linuxformat@futurenet.com, be picked as Letter Of The Month and win* a 32GB Nitrokey Storage 2! The Nitrokey is worth a cool €149, has 32GB of hardware-encrypted storage, supports hidden volumes, secures your online accounts with onetime passwords, can encrypt emails, files and hard drives and is an open source, open hardware solution. Protected with AES-256 and RSA keys up to 4,096! Learn more at www.nitrokey.com.…

Like the other “Super”-branded GPUs launched recently by Nvidia, the 1650 Super represents modest improvements to an existing part. In this case, the part is the TU116. That’s a step up from the bottom Turing TU117 GPU used in the GTX 1650. Why the change? Simple: The TU117 lacks a few of the extra features found in its big brother. Specifically, it uses the older Pascal-era NVENC block that promises better quality than x264 Fast encoding via the CPU, with a minimal hit to frame rates, as well as GDDR6 support. In terms of core specs, the GTX 1650 Super is a healthy jump in performance from the existing GTX 1650. It has 42 per cent more GPU cores, and while it sticks with a 128-bit memory interface, the move…

As the browser is one of the most indispensable applications on the desktop, it’s important to be able to run it without constantly worrying about resource usage. So the most important criteria for this Roundup is the performance. That said, we’re not using any scientific test to measure the resource usage, opting instead to report the results of pmap. In addition to comparing the memory usage at launch, we’ll repeat the test after extensive usage of the browser, accessing various popular websites as well as different types of content. We’re also interested in the security and privacy features that you can expect from these apps. These features, however, should not come at the cost of usability. Also important is the ability to get additional features through extensions and plugins. We’ve…

If you’ve grown tired of your current browser, there are still many more alternatives than just the ones we’ve featured in this Roundup. One of the oldest, and the winner of the lightweight browsers Roundup in LXF 213 is Midori. You’ll find it in the software repositories of most distributions. Opera is a good alternative if you want a build-in VPN service to access blocked websites. There are even text-based alternatives such as Links or Lynx. Seamonkey shares its codebase with Firefox, but is developed entirely by the community without any interference from Mozilla. The suite comprises a browser, IRC chat client as well as a mail and newsgroup client. Also based on Firefox ESR, the Tor browser is aimed towards providing users with anonymity, but it is not intended…

UEFI, the modern replacement for the BIOS, should make things much cleaner. Instead of relying on a Master Boot Record to point to a bootloader on a disk (you can’t fit a whole one in the 440 bytes provided), UEFI uses a FAT32 partition to store EFI images to do much the same thing. There should only ever be one such partition (even if you have multiple drives), and as OSes are installed they can add their own EFI images to this partition. Which OS to boot can be selected from the UEFI interface, so there should no longer be any issues with one OS depriving you of access to others, even if they’re located on the same drive. When it first appeared, UEFI was much maligned, in part because…

Don’t forget to back up your phone. We carry a lot of information on these devices, including photos that cannot be replaced. You could look for a backup program for your phone’s OS, or you could synchronise your phone with another service. Many cloud providers have an app to copy photos etc. to your storage. Alternatively, you could use something like Syncthing (https://syncthing.net) to synchronise your mobile devices with your computer whenever you connect to your local network, and then include them in the normal run of backups.…

Eight years ago we were all in a right jam when it came to building smart, Linux-based projects, but then the Raspberry Pi was born and combined with Linux, suddenly making smart IoT physical projects become as easy as pie. It’s simply mind-blowing how far the Pi has come in that time – with 30 million sales under its belt it’s now comfortably the third best-selling general-purpose computer ever. Only the Mac and PC have sold more units. To celebrate, the Raspberry Pi Foundation is offering swag bags to Jams that are being run between 15 February and 15 March in 2020. You’ll obviously need to be registered as a Jam and fill out the form linked below, and they also ask you to register six weeks before your event,…

Node-RED is a powerful programming language that requires no code to be written – rather we connect nodes containing functions together to perform a task. When used with MQTT (Message Query Telemetry Transport–a lightweight protocol to send and receive data) we can create applications that can talk across the world. In this tutorial we’ll build an Internet of Things temperature probe with built-in OLED screen. All powered by a Raspberry Pi. The DHT22 sensor is an affordable and simple sensor to work with and works well for breadboard use. It requires a 10K Ohm resistor between 3V and pin 2 (data), which ensures that the data pin is always pulled up. The OLED screen connects to the I2C pins of the Raspberry Pi. See the diagram for pin connections. Power…

For the ultimate media experience, you need the ultimate media server – and Plex (www.plex.tv) is just that. This is a client/ server solution that uses a media server – in this case a Pi 4 – on your home network. The server contains all the local audio and video files that you want to use. Plex can serve these files to multiple users and multiple devices at once; it can also transcode videos on the fly, so that your device receives the best possible quality. Plex Media Server for Raspberry Pi 4 is easy to install – you just need to take each step carefully and slowly. There is a great guide at https://pimylifeup.com/raspberry-pi-plex-server. So why is Plex so good? It offers the ability to stream your local content…

Three simple ways to access the boot partition. First, open it with the microSD card attached to your PC; or access the boot partition when Raspbian is running. Changes won’t take effect until the Pi reboots. The boot partition can also be accessed remotely via SSH. Booting from a USB hard disk or solid state drive will prolong the life of your Pi’s microSD card. While you’re unlikely to reach your card’s maximum write-cycle, relying on USB drives reduces the data corruption issues that come with unscheduled shutdowns. Using multiple Raspberry Pi SD cards? It’s easy to lose track of which card stores which operating system(s). A quick and easy fix is to create a new empty text file in the boot partition, describing the OS installed. You might call…

Fans of USA Network / Amazon Prime’s Mr. Robot will have seen the protagonist, Elliot, using what’s referred to as a “Pwn Phone” – a heavily customised mobile phone with a host of tools for hacking on the go. Of course, the television show is completely fictitious, but many of the tools and props are based on real-life (there are Raspberry Pis in there too) counterparts. Kali Linux NetHunter is a prime example, a fantastic custom Android ROM designed for mobile penetration testing. This is an OS that turns your phone into a portable hacking station. Kali Linux NetHunter from Offensive Security comes complete with a custom kernel, Kali Linux chroot, and a suite of Android applications designed around cyber security. While Kali Linux NetHunter is prime for mobile/WiFi penetration,…

The Network Spoofer app makes a great addition to the KLN toolkit. When enabled, the app looks out for devices trying to connect to WiFi access points and spoofs the names of those access points. The app then lets users connect to your phone and access the internet via your 3G/4G connection. But unlike a regular WiFi tether you have the option to play with their content. Change YouTube videos to play Rick Astley videos instead of whatever they’re trying to watch. Custom image change can switch out images. Custom direct can send targets to websites of your choosing. You can delete random words, flip content or turn images upside down. ‘Website gravity’ makes all elements of the website fall to the bottom of the page. ‘Wobble images’ makes images…

If you want to see some of these circuits working in actual hardware – a 4-bit adder would be a good choice because the circuit is interesting but of manageable proportions – there’s absolutely no reason why not. Unlike building logic gates, your basic building blocks will be logic gates. As a 1-bit adder requires two XOR gates, two AND gates and an OR gate, a 4-bit adder will need eight XOR gates, eight AND gates and four OR gates. Gates don’t come as single components but as small 14-pin or 16-pin ICs that typically contain four two-input gates, all of the same type. So, for our example of a 4-bit adder, you’d need two XOR gate chips, two AND gate chips and one OR gate chip. There are actually…

EVERNOTE DESKTOP CLIENT Quentier Version: 0.5 Web: https://github.com/d1vanov/quentier Making the most out of the Evernote service does not necessarily require you to install the official Evernote client. This time we will be stepping out of the walled garden in order to replace the official Evernote desktop client with something new. Quentier is a very promising candidate for that, and even a brief usage showed that our Evernote notebooks load up and work just right. The very first time you start Quentier it shows a setup wizard and suggests you log in to your Evernote online account. The available options enable you to proceed with a Google authentication or continue with local settings. For everyone use to writing down notes in the mobile version of Evernote it makes sense to authorise…

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…

“Well so far so good – I haven’t been extraordinarily rendered following my incendiary hacking feature last issue. And hopefully no one tries to lynch me as a result of my perpetuating the myth that anyone can switch to Linux. This whole pretend tech journalism lark is a hazardous occupation. You really should switch to Linux though, it’s great. For many years I have held the secret suspicion that self-anointed “Windows power users” are the ones that have most difficulty with Linux. Now I make this suspicion public. The thing is, those people really make life difficult for themselves. Those skills don’t transfer over to Linux at all. If you go looking for out-of-tree drivers before you learn that most hardware is supported in the kernel, or if you go…

Nvidia has been less accommodating when it comes to supporting open source drivers for its graphics cards compared to AMD, but it’s recently been softening its stance. In 2019 Nvidia extended a helping hand to the developers working on Nouveau, the open source Linux driver for its GPUs, with the release of hardware documentation to aid the project. That move came as a welcome surprise, and at the upcoming GTC (GPU Technology Conference). which runs 23-26 March 2020, John Hubbard, principle SW engineer at Nvidia will host a talk titled “Open Source, Linux Kernel, and Nvidia”. According to Nvidia’s website (http://bit.ly/LXF259Nvidia), the talk will discuss Nvidia’s future plans for contributing to the Linux kernel, as well as its ongoing support for Nouveau. Hopefully this is an indication that Nvidia will…

“PipeWire, (see LXF232) the new open source framework that aims to greatly improve the exchange and management of audio and video streams inside a Linux system, has seen a number of improvements and bug fixes over the past year. At Collabora, we have been busy helping clients work with PipeWire, notably Automotive Grade Linux, which has chosen to adopt PipeWire for its implementation of the low-level platform audio service, replacing previous solutions like 4A, PulseAudio and AudioManager. Assisting early adopters such as AGL has brought us to design and implement new elements within PipeWire, such as the session & policy management component WirePlumber, which George Kiagiadakis presented at the GStreamer Conference in Lyon. In addition to WirePlumber, we have now implemented a new tool to simplify and ease the debugging…

Rijo Thomas posted “Add TEE interface support to AMD Secure Processor driver”, that teaches the kernel how to talk to a TEE (trusted execution environment) running within a separate co-processor built into certain AMD chips. The AMD Platform Security Processor (PSP) is a “dedicated processor which provides TEE to enable HW platform security” and enables certain code to be run where it can’t easily be introspected by potential attackers. TEEs are generally favoured for use in certain cryptographic regimes, or for DRM purposes. Thara Gopinath posted an updated patch series titled “Introduce Thermal Pressure”, that aims to teach the kernel about how to handle the impact of thermal events on the scheduling of tasks (processes). Typically, when a processor overheats (such as in a heavily loaded phone), the CPU will…

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 an illegal alien), 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…

No matter how responsive or quick to launch a browser may be, you’ll only care for these alternatives if they can properly render the websites you visit and accurately display the content you cherish. For this reason, we subjected each of these alternative browsers to the Acid3 and the HTML5 tests. As the name suggests, the latter test is used to determine how well the browser supports HTML5. Refer to the websites of these tests to understand the scoring and what it means. Generally speaking, for all such benchmarking tools, a higher score is desirable. On the Acid3 tests, all the browsers scored 97/100, except for Pale Moon, which managed 99/100. This is not necessarily a bad thing as most modern browsers now fail the Acid3 test and are unable…

In April 2014 Windows XP, loved by some, a thorn in the side of others, went End of Life (EOL). There would be no more bug fixes, and no more security updates. Anyone who continued to use it was on their own. Users had the choice of updating to the newly released Windows 8.1 (though its Metro interface was unpopular and its system requirements were considerably higher than XP’s) or 2007’s Windows 7, which we can rightly describe as the least worst Windows release of the last 20 years. At the same time, Ubuntu 14.04 had just been release, as had LXF187. We shamelessly took advantage of this coincidence to remind people that there was another way. And that way was Linux. And here we are, pulling exactly the same…

The first thing you should do after making your first backup is to make sure you are able to restore from it. Most backup software has an option to test the integrity of the backups after creating them, but a real test to make sure you are able to get your files out of the backup is well worth the time. Another point to consider is how you will restore your backups if your OS filesystem is hosed. You will need the software you used to create the backup in order to restore it, so make sure you have a copy of that quickly available in case something bad happens.…

There are a couple of technologies that are often discussed in the context of backups, but aren’t really backups. RAID, in all levels but RAID0, means that if you have a disk failure, your data will still be safely stored on at least one other disk. Swapping out the failed disk and letting the RAID array rebuild will keep your data safe against a future failure. However, it won’t help if you delete files you shouldn’t, or if your computer catches fire! So it’s not a backup. Advanced filesystems like ZFS and Btrfs have a snapshot feature. This enables you to quickly take a snapshot of your filesystem, allowing you to roll back if something goes wrong at the file level. As the snapshots are almost instant and take up…

In June 2019 the Raspberry Pi 4 surprised everyone in the Pi community, and the release was full of hidden surprises. The power of the Pi 4 is almost enough to replace your desktop PC – if you only send emails and do some light web surfing. This extra power means that your new Pi 4 runs hotter than any model before it, and so active cooling is the order of the day. But wait! Those clever engineers at Raspberry Pi Trading have released a firmware patch that will cool your Pi 4 and more! In the latest firmware update the Pi 4 has a new bootloader that can now boot over Ethernet (sorry no Wi-Fi booting yet) offering users the chance to create their own thin client. But this…

In this tutorial we sent temperature data via MQTT, which was fed back to the Pi, but what if we could see this data on our smartphones? Well we can. MQTT works across many different devices and there are clients available for Android and iOS. We used the MyMQTT app for Android, this free app enabled us to receive the raw temperature data. We entered the MQTT broker into the Settings section, and then entered the topic LXF_Temp into the Subscribe menu. Then in a few seconds we started to receive live sensor data. Using the same app we could also send (publish) a message from our smartphone to the Pi and see the message in the debug output. MQTT is a powerful yet lightweight protocol. It can work on…

The Raspberry Pi 4 can generate a lot of heat; even at idle, it’s around 39°C. If you push the Pi too hard it’s possible for it to reach 80°C, which will mean thermal throttling drops the speed of the CPU from 1.5GHz to 1GHz in an effort to cool it down. Running the Pi 4 at high temperatures is not detrimental to the system. In fact, it can survive temperatures far hotter than that; it is reflowed in a solder oven at 250°C, as confirmed by Eben Upton on Twitter! With the latest firmware, which we installed in this tutorial, we can reduce the temperature of the USB 3 controller chip which contributes to cooling the Pi 4, but we still need some form of passive (heatsink) or active…

Booting a Raspberry Pi is usually straightforward. However, if it refuses to boot, make the following checks. First, watch the LEDs. The red power (labelled PWR) and the green activity (ACT) LEDs are used to indicate changes in status. For example, the ACT LED will flash when there is data activity on the SD card. PWR will blink when power drops below 4.65V. Meanwhile, if the PWR LED lights up but there is no ACT, there is no boot instruction on the SD card. The ACT LED can also indicate error statuses. For instance, four flashes mean the start.elf file cannot be found, while seven flashes tells us that kernel.img is missing. Second, consider the PWR LED. If the power is dropping, it’s likely that the Pi’s power supply is…

Offensive Security is always looking for new devices to port Kali Linux NetHunter to. If you’re interested in getting involved or supporting this open source project, head over to https:// github.com/offensive-security/kali-nethunter/ wiki/Porting-Nethunter Operating Linux on a smartphone is a fun novelty, but it can be difficult to type out long strings of text on a touchscreen keyboard. We’d highly recommend getting yourself a Bluetooth keyboard to interface with, you will thank us later! Remember, if you’re doing anything while connected to the internet be sure to use a VPN. This should be a good rule of thumb for everything – whether you’re pentesting or just browsing, always use protection!…

Black and white photos can look very dramatic in some instances. We’ll leave you to learn which subjects really lend themselves to this – although scenes with lots of contrast and texture often look good – but we will provide a bit of guidance on converting a photo to B&W. This suggests that you should always shoot in colour, and that’s undoubtedly true because it offers you much more flexibility. The simplest method is to select Image>Mode>Greyscale. This might provide an acceptable result, but it’s very similar to what your camera would do if you shoot in B&W, and offers no options. It considers all colours as equal, so the end result might exhibit poor contrast. Since good B&W is often high-contrast photo, you could do better by carrying out…

It might not form part of the CPU, but because memory is so closely tied up with a microprocessor, a brief word on memory circuitry would be appropriate. We’ve already seen memory that’s internal to the CPU in the form of registers made from D-type latches. However, since the simplest comprise an inverter and four gates, each of which requires a minimum of two transistors, a few gigabytes of RAM made from D-type latches would consume serious real estate on a chip. Memory made from D-type latches is an example of static RAM (SRAM), but the alternative dynamic RAM (DRAM) is more frugal in its transistor use. Each bit is a cell that uses a single transistor plus a capacitor, so that 0s and 1s are represented by the absence…

You may well be wondering which of this plethora of dialog box libraries to use. If you can’t make up your mind, then a good choice is the EasyBashGUI library (https://github.com/BashGui/easybashgui) this makes the choice for you. Depending on which desktop is running on your system, it may create a component using yad, gtkdialog, kdialog, zenity, Xdialog, (c)dialog, whiptail, or Bash built-ins. We’ll finish up this article with a discussion about EasyBashGUI. Dialog was originally developed by Savio Lam, but was given a major overhaul by Pasquale De Marco and renamed cdialog (as it was coded in C). Cdialog has mostly replaced the now-defunct dialog, and has largely taken over its name. (C)dialog should not be confused with gtkdialog, kdialog, or Xdialog, these are all GUI-based versions of the library…

A Grafana data source is a database, file or service that provides data to Grafana – it cannot operate without data. A Grafana panel is the basic building block of Grafana. Panels are made of visualisations or queries. A Grafana query is used for requesting data from a data source. A visualisation is a graphical representation of the data returned by a query. Grafana dashboards are made off rows and panels – a row can have multiple panels, which you can edit if you want. Lastly, a plugin is a Grafana extension that adds more functionality to a Grafana installation. Time series databases are databases that store time-stamped data, which means that you will have to work with dates and times. Time-series data includes data like stock trades and quotes,…

USING THE LXFDVD Using Linux for the first time can be very confusing. It’ll be unlike anything that you’ve likely 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) 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 boot from a…