Linux MagazineMay 2021的目錄

Dear Reader, Is the web changing before our eyes? We in tech media certainly talk about change all the time. (One could argue that the whole point of tech media is to talk about change.) And of course, big tech companies are always on the message of change. In all my years in the business, I don’t think I’ve ever read a press release that said “Nothing happened! Everything is still the same!” When you look at how far the tech world has come over the last generation, it would be fair to say that things must be constantly changing, or we wouldn’t have come so far so fast. But given the constant rumble, it is prudent to wonder how much of that change is meaningful and real. The big…

On the heels of the alpha release of Gnome 40, the developers have announced the availability of the beta, which includes a number of improvements and bug fixes. Of course, the biggest change to Gnome is the new horizontal Activities Overview, which makes for a much-improved workflow on the desktop. With the desktops residing at the top of the Overview, it is now easier to drag and drop an application to the specific desktop you want. It’s far more intuitive and efficient. This new layout also improves usage with touch screen navigation and faster overall performance. Another hotly anticipated change comes by way of how multi-monitor support will work with the new horizontal Activities Overview. Gnome 40 will default to only showing workspaces on the primary display, with the top…

Ubuntu 20.04.2 has already shipped and the developers found themselves in a tricky position with Thunderbird, the popular open source email client. Essentially they had two choices: • Backport individual security fixes to Thunderbird 68.• Port the latest version. One of the most important aspects of Ubuntu is stability. Because of this, the platform doesn’t generally ship with the latest releases of software. And initially Ubuntu 20.04 shipped with Thunderbird 68. However, because that version is no longer supported by upstream, it would no longer be receiving security updates. That’s a problem. So the Ubuntu developers had to choose between two options. Fortunately, they opted to go with porting the latest version of Thunderbird. This will cause an issue for some users, as not all Thunderbird extensions will work with…

Modern CPU cores do not run constantly at the maximum possible clock speed, but instead, are capable of scaling the computing power up or down in defined steps as needed in order to save energy. On Linux, this task is performed by the CPU Frequency Scaling system (cpufreq) [1], which is built into the kernel. Several different approaches or philosophies exist for how to accelerate the system. Is it better to immediately ramp up the clock speed to the max for a computing task, or should the system gradually increase the computing power? The CPU needs a large amount of energy at the highest clock speed, but, when it is running at a high speed, it completes the computing task more quickly, so that the CPU can go back to…

Python apps on lower-end hardware like Raspberry Pis can be a bit slow, but luckily you have some options that can improve their performance. A number of interesting packages allow you to compile, interpret, or repackage your Python apps. In this article, I highlight two packages that have given me good success: • PyPy [1] – a replacement to the native Python interpreter that runs more than four times faster• Nuitka [2] – a native Python utility to compile Python apps to C code How a Python application performs is based on a lot of different factors, so it’s important to know the limitations and how best to work with them. PyPy and Nuitka might not work for all applications, but for many common types of projects they are great…

Open Source Ingenuity In the middle of the night a friend sent me a message about NASA designing a heavier-than-air drone named Ingenuity to fly on the planet Mars. Even though I had finished my article for this month I knew I had to scrap it and write about Ingenuity, built mostly with off-the-shelf components and Free and Open Source Software (FOSS) which has several real-world (and even Mars-world) ramifications. The Mars rovers are machines that “have to work.” The cost of designing them, launching them, and managing them is tremendous. Not working after all of that expense and time is something that needs to be avoided at all costs. Plus the operating environment on Mars is so unlike anything on Earth that extra care has to be taken with…

Sparkling gems and new releases from the world of Free and Open Source Software Flight simulator MScSim The clue to the seriousness of this flight simulator is in its name, “MScSim.” The developer is also responsible for an earlier project called “BScAero,” and we can only assume these projects represent milestones in the developer’s ongoing education from “Bachelor of Science” to “Master of Science.” This is backed up by a mathematically intense document that accompanies MScSim entitled “Flight Dynamics Model for the Real-Time Flight Simulation” (itself released under a Creative Commons Public Domain license). The paper is difficult to understand without some prior insight into how flying works, but it does presumably illustrate how accurate the flight model in the simulator is. If you want to learn how to fly,…

We are always looking for good articles on Linux and the tools of the Linux environment. Although we will consider any topic, the following themes are of special interest: • System administration• Useful tips and tools• Security, both news and techniques• Product reviews, especially from real-world experience• Community news and projects If you have an idea, send a proposal with an outline, an estimate of the length, a description of your background, and contact information to edit@linux-magazine.com. The technical level of the article should be consistent with what you normally read in Linux Magazine. Remember that Linux Magazine is read in many countries, and your article may be translated into one of our sister publications. Therefore, it is best to avoid using slang and idioms that might not be understood…

OpenMandriva is a direct descendant of the not forgotten (and much-loved) Mandriva Linux, and was the first to ever make use of the LLVM toolchain by default. With the release of Lx 4.2, OpenMandriva brings to the table a few improvements, as well as the latest release of the KDE desktop environment, and some exciting ARM news. As for software, OpenMandriva improves the OM Welcome, which is an on-boarding tool that makes it incredibly easy for new users to do things like install software with a single click. Beyond the welcome app, OpenMandriva includes LibreOffice 7.1, Krita 4.4.2, Digikam 7.2, SMPlayer 21.1.0, VLC 3.0.12.1, Falkon browser 3.1, Simple-ScreenRecorder 0.4.3, and much more. Also included with OpenMandriva is Desktop Presets, which allows users to easily customize the appearance of the Plasma…

Spectre has been in the public knowledge base since January 9, 2018, when Intel was forced to go public with the information that all of their CPUs (since 1995) can allow applications to be tricked into leaking information they hold in memory. Since then, there have been a number of Spectre exploits, across all operating systems on Intel hardware. Recently a French researcher, Julien Voisin, announced (https://dustri.org/b/spectre-exploits-in-the-wild.html) he was able to view the contents of /etc/shadow on a vulnerable Fedora system, thereby verifying this new Spectre exploit. This vulnerability works in four stages: • Finding the superblock of a file.• Finding the inode of the file to be dumped.• Finding the corresponding page address.• Dumping the contents of the file. According to Voisin, this exploit had a 0 detection rate…

CPUs, RAM modules, and storage media keep getting faster, but today’s Linux systems are still a little too slow at startup for many busy users. With a few useful tools and a little knowledge of the Linux environment, you can shave some seconds from the startup process. Read on for some insights. systemd-analyze The systemd-analyze tool supplied with systemd gives a first impression of where time is being wasted. The time option outputs the total startup time and shows what portion of that time is used for firmware, bootloader, kernel, and user space: Listing 1 shows the output, which will vary depending on you firmware, hardware, and software configuration. Test Setup The test system for this article was a four-year-old Tuxedo BU1406 with a “Kaby Lake” Intel i7-7500U CPU, 32GB…

The coronavirus pandemic has the world in its grasp. With social distancing and family dispersion, many people are not able to see their grandchildren. Even a cellphone is too complicated for some senior citizens, and they may not want to have anything to do with PCs. One alternative could be an Internet-enabled baby monitor with a return channel, but it won’t have video. Besides, grandma and grandpa don’t want to be monitored, and you don’t want the baby monitor to alert you every time your grandparents walk past the device. Jitsi and WebRTC Today, many multimedia applications such as audio or video calls no longer require separate programs such as Skype. The free WebRTC [2] standard enables modern web browsers to send voice, video, and data directly from user to…

Order online: https://bit.ly/Linux-Newsstand #245/April 2021 Choose a Shell You’re never stuck with the same old command shell – unless you want to be. This month we review some of the leading alternatives. On the DVD: Arch Linux 2021.02.01 and MX Linux mx-19.03 #244/March 2021 Stream Processing The explosion of real-time data from sensors and monitoring devices is fueling new interest in alternative programming techniques. This month we wade into stream processing. On the DVD: FreeBSD 12.2 and GhostBSD 20.11.28 #243/February 2021 iNet With Linux, more innovation is always on the way. This month we take a look at the iNet wireless daemon, a new wireless client that is poised to replace the venerable WPA Supplicant. On the DVD: Linux Mint 20 and Kali Linux 2020.4 #242/January 2021 3D Printing The…

NVIDIA Optimus laptop users rejoice, Mageia 8 now includes improved support, thanks to an upgraded graphics stack that includes Mesa 20.3.4 and X.Org Server 1.20.1. This upgrade improves both the AMD and NVIDIA GPU experience with the platform. For NVIDIA users, there’s the new experimental mageiaprime configuration tool that makes it possible to get the most out of your NVIDIA GPU. But the new release isn’t all about the graphics stack. Anyone who begins Mageia 8 with a live instance will see faster performance, thanks to the inclusion of Zstd compression on the base file systems, and better optimizations for hardware detection. NFS file system support has also been improved, with added support for NFSv4. Mageia also includes a new version of RPM (version 4.16.1.2) which offers a number of…

Linux Magazine www.linux-magazine.com ADMIN HPC http://www.admin-magazine.com/HPC/ How Linux and Beowulf Drove Desktop Supercomputing • Jeff Layton Open source software and tools, the Beowulf Project, and communities changed the face of high-performance computing. ADMIN Online http://www.admin-magazine.com/ HTML to Database with a Perl Script • Thomas Valentine A Perl script strips HTML markup, creating text files, and makes each file an entry in a database. Managing Access Credentials • Erik Bärwaldt Most Internet services require passwordprotected individual accounts. A password manager can help you keep track of all your access credentials. Hardware Suitable for Cloud Environments • Martin Loschwitz If you want to build scalable clouds, you need the right hardware, but which servers are the right choice as controllers, storage, and compute nodes?…

Author The Linux kernel mailing list comprises the core of Linux development activities. Traffic volumes are immense, often reaching 10,000 messages in a week, and keeping up to date with the entire scope of development is a virtually impossible task for one person. One of the few brave souls to take on this task is Zack Brown. Opening a Random Can of Worms Torsten Duwe was mad as hell, and he wasn’t going to take it anymore! Or at least, he had certain objections to /dev/random, which he felt should be addressed. In particular, one of the main points of random numbers in the Linux kernel is to support system security. Torsten pointed out that “Input entropy amounts are guesstimated in advance, obviously much too conservatively, compiled in and never…

The Quicksort sorting algorithm has been around for 60 years, and, if implemented properly, it is still the fastest option for many sorting tasks. According to the description on Wikipedia, a well designed Quicksort is “…somewhat faster than Merge sort and about two or three times faster than Heapsort.” Many Linux users today have studied Quicksort at some point in the past, through a computer science class or other training scenario, but unless you are working as a professional programmer, chances are it has been a few years since you have taken the time to ponder the elegant Quicksort algorithm. Still, sorting goes on all the time on Linux networks. You don’t have to be a fulltime app developer to conjure up an occasional script to rank results or order…

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