If there’s only lesson to be learned from [alnwlsn]’s conversion of an IBM Selectric typewriter into a serial terminal for Linux, it’s that we’ve been hanging around the wrong garbage cans. Because that’s where he found the donor machine for this project, and it wasn’t even the first one he’s come across in the trash. The best we’ve ever done is a nasty old microwave.
For being a dumpster find, the Selectric II was actually in pretty decent shape. The first couple of minutes of the video after the break show not only the minimal repairs needed to get the typewriter back on its feet, but also a whirlwind tour of the remarkably complex mechanisms that turn keypresses into characters on the page. As it turns out, knowing how the mechanical linkages work is the secret behind converting the Selectric into a teletype, entirely within the original enclosure and with as few modifications to the existing mechanism as possible.
In a session at the 2023 Real Time Linux Summit, Thomas Gleixner answered questions about the realtime feature of the kernel, its status, and the Real-Time Linux project's plans for the future. The talk was billed as a "Q&A about PREEMPT_RT" with a caveat: "anything except printk() and documentation". As might be guessed, the first two questions were on just those topics, but there were plenty of other questions (and answers) too. The summit was held in conjunction with the inaugural Embedded Open Source Summit in Prague, Czechia at the end of June.
The time_t rollover is still over 14 years away, so solving it might not appear to be an urgent problem. The fact that it does not affect most 64-bit systems may also encourage complacency. But there are affected 32-bit systems on the market now, and some of them are likely to still be operating in 2038; that is especially true of embedded systems, which might prove harder to fix as the date approaches. It would be far better if these systems were prepared for 2038 at deployment time; that means solving the problem as quickly as possible.
Work has been underway in the kernel for some years, and it is mostly free of year-2038 problems at this point. The GNU C Library (glibc) has also seen a considerable amount of work to allow it to handle both 32-bit and 64-bit time_t values, depending on how a program has been compiled. So the core of a Linux system is ready, but there is a lot more than that to the problem.
The page structure sits at the core of the kernel's memory-management subsystem; one such structure exists for every page of installed RAM. This structure is increasingly seen as a problem, though, and phasing it out is one of the many side projects associated with the folio conversion. One step in that direction is currently meeting some pushback from memory-management developers, though, who think that some of these changes are coming too soon.
The purpose of struct page is to allow the kernel to keep track of the status of each page — how it is being used, its position in a least-recently-used list, how many references to it exist, and more. The information needed varies considerably depending on how a given page is being used; a page of user-space anonymous memory is managed differently from, say, memory used for a kernel-space DMA buffer. Since page structures must be kept as small as possible — there are millions of them in a modern system, so every byte hurts — data must be stored as efficiently as possible. As a result, struct page is declared as a maze of nested unions, allowing the data fields for each usage type to be overlaid.
The kernel-development process routinely absorbs large changes to fundamental subsystems and still produces stable releases every nine or ten weeks. On occasion, though, the development community's luck runs out. The per-VMA locking work that went into the 6.4 release is a case in point; it looked like a well-tested change that improved page-fault scalability. There turned out to be a few demons hiding in that code, though, that made life difficult for early adopters of the 6.4 kernel.
The mmap_lock controls access to a process's address space. If a process has a lot of things going on at the same time — a large number of threads, for example — contention for the mmap_lock can become a serious performance problem. Handling page faults, which can involve changing page-table entries or expanding a virtual memory area (VMA), has traditionally required the mmap_lock, meaning that many threads generating page faults concurrently can slow a process down.
Developers have been working for years to address this problem, often pursuing one form or another of speculative page-fault handling, where the work is done without the protection of the lock. If contention occurred during the handling of a fault, the kernel would drop the work it had done before making it visible and start over. This work never got to the point of being merged, though. Eventually, Suren Baghdasaryan's per-VMA locking work was merged instead. Since a page fault happens within a specific VMA, handling it should really only require serialized access to that one VMA rather than to the entire address space. Per-VMA locking is, thus, a finer-grained version of mmap_lock that allows for more parallelism in the execution of specific tasks.
The extensible scheduler class enables the creation of CPU schedulers in BPF. After the fourth version of this series was greeted with relative silence, Tejun Heo asked about the status of this work...
All users of the 6.4 kernel series must upgrade.
The updated 6.4.y git tree can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git linux-6.4.y and can be browsed at the normal kernel.org git web browser: https://git.kernel.org/?p=linux/kernel/git/stable/linux-s...
thanks,
greg k-h
Today, we hear of people "distro hopping." Some of us may be guilty of it. It's hard to resist, trying out that new Linux distro with the new features. Even I am not immune, and I have a couple of laptops that I routinely try a new OS (or older if I'm feeling nostalgic) on.
There was a time though, when distro hopping wasn't common as there were fewer distros in the beginning days of Linux. What many of us early users did instead was to play around with different window managers.
Compiz was one of those window managers, released in 2006. It is one of the oldest compositing window managers for the X Window System and it was quite advanced for its day. Window managers aren't as popular as they once were, but Compiz is still maintained, still has remarkable performance and a large number of features.
Odoo is a full-featured, extensible open-source ERP (Enterprise€ Resource€ Planning) software built using Python and PostgreSQL database for data storage.
It is a suite of open-source business applications, that consists of multiple apps under various categories such as website, sales, finances, operations, manufacturing, human resource (HR), communication, marketing, and customization tools.
Occasionally, while dealing with files in a Linux terminal, you may want to clear the content of a file without necessarily opening it using any Linux command line editors. How can this be achieved?
In this article, we will go through several different ways of emptying file content with the help of some useful commands.
Sometimes when you try to ping a website, update a system or perform any task that requires an active internet connection, you may get the error message ‘temporary failure in name resolution’ on your terminal.
For example, when you try to ping a website, you might bump into the error shown...
In our previous article, we have seen 20 Netstat Commands (netstat now replaced by ss command) to monitor or manage a Linux network.
This is another ongoing series of packet sniffer tools called tcpdump. Here, we are going to show you how to install tcpdump and then we discuss and cover some useful commands with their practical examples.
Odoo is an open-source business platform that comes with a vast set of productivity apps allowing you to deal with what an average company needs — sales, CRM, electronic commerce, project management, human resources, accounting, inventory, marketing, etc.
The built-in Odoo marketplace makes it possible to create a highly customizable platform that can be easily adapted to any business by installing the required apps. The choice is so extensive that exploring all the available integration options might take a lot of time.
If you work in IT, you may have been lucky enough to take home some hardware your company was going to donate, or recycle. Whether its a few small form factor workstations or a giant enterprise grade server, they can be a great tool for learning on your own. A similar situation is what started my homelab. My previous boss was going through his garage, and was getting rid of boxes and boxes of old IT equipment. He asked if I wanted to pick through it all before he donated it. I did exactly that, and came out with a bunch of cool stuff. One of those items was an old Lenovo workstation running Windows 7. As you know, Windows 7 is pretty old. Released in 2009, and support ended in 2020. Not something we want on our network , even if its going to be used for internal use. That leaves us 2 options:
Before installing a new package, you need to check if it’s already installed on your system. Additionally, if you are shifting to a new system, having a list of all the installed packages can save you significant time and effort. It can also facilitate you in identifying unwanted packages that you want to remove to free up some space.
Here's how to list all installed packages on various Linux distributions including Ubuntu, Debian, CentOS, Arch Linux, and openSUSE.
Bash scripts have been around since the humble beginnings of Linux. But what are they and how do you create your first one? Find the answers to those questions here.
The security of Linux servers is of paramount importance in today's digital environment where cyber threats are constantly evolving. One such critical vulnerability requiring immediate action is the PwnKit vulnerability, identified as CVE-2021-4034.
Let's examine the nature of this vulnerability, its potential impact on Linux servers, and most importantly, ways to effectively patch and secure your Linux server against this threat.
It’s important to keep your system packages up-to-date because you can quickly upgrade your PC’s software and enjoy all the latest features and fixes. If you’ve encountered an error like “hash sum mismatch” on Linux, this routine task can quickly become frustrating.
The event took place over at the Geekerwan YouTube channel, where the tech-tuber explains the extremely painful process of getting first Android, and then Ubuntu Linux, onto the Nintendo Switch.
This seems like a game bundle not to be missed if you're an RPG fan. Humble Bundle has teamed up with Beamdog for the RPG Legends: Baldur's Gate & Beyond.€ Using the usual rating system of Deck Verified,€ ProtonDB€ and Native Linux notes to save you clicking around. Each game title is also a Steam link in case you need more info first.€
A city-building colony-sim where a bunch of Beavers are building a society long after us pesky humans died off is not a thing I thought I needed but Timberborn is properly great. Note: key provided by Evolve PR.
Want to make games but don't know how to code? The free and open source GDevelop is a great cross-platform tool with an events-driven system.
With the Summer Event live until September 15th, 2023 it seems Valve still aren't quite done updating Team Fortress 2 with the renewed popularity. Team Fortress 2 managed to smash it's all time player record at€ 253,997 around 2 weeks ago, but it's settled back down to around 100,000 now.
Okay now THIS is exciting as heck. Armored Core VI Fires Of Rubicon will be "fully supported" on Steam Deck according to FromSoftware.
This is great to see. Ratchet & Clank: Rift Apart from Insomniac Games, Nixxes Software and PlayStation is out on Steam today and it's Steam Deck Verified!
The KDE development team is gearing up for an exciting milestone as they prepare to unveil the highly anticipated Plasma 6 desktop environment. As the successor to the widely acclaimed Plasma 5, the latest iteration promises to bring a host of new enhancements and optimizations to the KDE ecosystem.
However, with progress often comes change, and to refine the user experience and streamline performance, KDE developers have announced their decision to remove certain features from Plasma 6.
Icons on the desktop!
The minimize button!
Visible Panels and docks!
Just kidding, don’t have a heart attack. Well actually there are some things… just not those! The full list can be found at https://community.kde.org/Plasma/Plasma_6#Removals, and it’s public; we’re not hiding anything! Today I wanted today provide a bit of context and explain the why, since it may not be obvious how it makes sense to remove things. So let’s go through the list...
Krita 5.2.0 is a major new release, and the first of the Krita 5.2 series of releases. Especially internally, there have been huge changes and improvements. While there are a lot of important user-visible changes that will make artists’ workflow smoother, most work has been inside Krita, preparing Krita for the future.
The release notes will give you all the details, but here are some highlights...
GNOME is a free and open-source desktop environment for Linux and Unix-like operating systems. It is one of the most popular desktop environments in the world and is used by millions of people via mainstream Linux distributions such as Ubuntu and Fedora alike.
The GNOME 45 release is expected to be a major update with many new features and improvements.
Let's take a look at the new improvements.
Unfortunately I couldn’t be at GUADEC this year, but that wont stop me from demoing new things!
I’ve been doing a lot of work on Sysprof now that we have semi-reliable frame unwinding on Fedora, Silverblue and GNOME OS. When I have tolling that works on the OS it makes it a lot easier to build profilers and make them useful.
Additionally, we’re at a good point in GTK 4 where you can do really powerful things if you design your data models correctly. So this cycle I’ve spent time redesigning how we record and process our captured data.
The next update for IPFire is available for testing! It contains more hardening features for modern processors and a large number of security fixes in third-party packages.
This update comes with extended hardening for the kernel by using Indirect Branch Tracking wherever possible. This will prevent hackers to hijack functions calls and jump into injected code. This feature is currently only supported on Intel processors.
In the near future, we will extend this feature to the user-space and more processor types.
Zorin OS 16.3 is here nine months after Zorin OS 16.2 and includes all the latest updates from the upstream Ubuntu repositories to provide those who want to deploy the latest Zorin OS 16 series on new computers with an updated live/installation media with top-notch hardware support and the most recent security patches.
Apart from shipping with all the latest updates from the Ubuntu 22.04 LTS repositories, as well as an updated software selection that includes the latest and greatest LibreOffice 7.5 open-source office suite series, the Zorin OS 16.3 release comes with a cool new feature out of the box, Zorin OS Upgrader.
The news of the time interval is that Red Hat has stopped making Red Hat Enterprise Linux source code generally available, although just as with the switch to 'CentOS Stream' from CentOS their article doesn't put it that way. This created difficulties for at least two CentOS replacement distributions, forcing AlmaLinux to change what they are. I don't have much to say on this specific topic, but it has sparked a series of exchanges about, for example, the history of RHEL rebuilds (via). As it happens, I have some views on why people would want to use a free 'clone' (rebuild) of RHEL, as CentOS was before it became CentOS Stream, partly based on personal experience.
Here are some major reasons people could want or need CentOS, at least back in the era of CentOS, before CentOS Stream became your only option from RHEL 8 onward: [...]
"Red Hat themselves did not reply to our repeated requests to join us on this panel... SUSE was also invited but let us know they were unable to send someone on short notice to Portland for the panel."
One interesting audience question for the panel came from Karsten Wade, a one-time Red Hat senior community architect who left Red Hat in April after 21 years, but said he was "responsible for bringing the CentOS team onboard to Red Hat." Wade argued that CentOS "was always doing a clean rebuild from source RPMS of their own..." So "isn't all of this thunder doing Red Hat's job for them, of trying to get everyone to say, 'This thing is not the equivalent to RHEL.'"
In response Jeremy Alison made a good point. "None of us here are the arbiters of whether it's good enough of a rebuild of Red Hat Linux. The customers are the arbiters." But this led to an audience member asking a very forward-looking question: what are the chances the community could adopt a new (and open) enterprise Linux standard that distributions could follow. AlmaLinux's Vasquez replied, "Chances are real high... I think everyone sees that as the obvious answer. I think that's the obvious next step. I'll leave it at that." And Oracle's Wright added "to the extent that the market asks us to standardize? We're all responsive."
There is an update of Sparky ISO images of the stable line 7.0.1 out there.
This is a minor update, it mainly fixed an issue of the live config, which did not let you launch password reqiured application without password in live session, such as: Calamares, APTus, GParted, Gufw, etc.
Now, the apps don’t need a password to be launched in live session (excluding MinimalGUI i686).
As usually, all packages have been upgraded from Debian and Sparky stable repos, as of June 26, 2023, so all updates of Debian 12.1 are included.
No reinstallation is required if you have Sparky 7 installed, simply keep Sparky up to date. The new iso images only fix the live session issue.
SolidRun revealed today two fanless PCs built around the 8-core AMD Ryzen 7040 Series CPUs along with up to three Hailo-8 AI accelerators to provide 78 TOPS AI performance. The Bedrock R7000 Edge AI has been designed to operate in diverse commercial and industrial applications including robotics, agriculture, transportation, etc. €
If you ever looked at a PCI to PCIe x16 adapter and wondered what’d happen if you were to stick a modern PCIe GPU in it, the answer apparently is ‘it works’ according to an attempt by [Circuit Rewind]. As long as you accept needing to supply external power with even a low-end GT 1030 card – as the PCI slot cannot provide enough power – and being limited to a single PCIe lane. This latter point isn’t so much of an issue as a single PCIe lane offers more bandwidth than the (shared) PCI bus anyway.
A really great one came out on the Debian mailing list this week. RISC-V is becoming a first-class citizen on Debian. RISC-V has now been accepted as an official architecture. This is huge news for the RISC-V community.
Although many boards have microphones and can run sound recognition machine learning models, the Nicla Voice contains a Syntiant NDP120 Neural Decision Processor that is specifically designed to accelerate deep learning workloads while also decreasing the amount of power needed to do so. Apart from the board, Kumar added an Adafruit DRV2605L haptic motor driver and haptic motor as a way to wake up the user without disturbing others nearby.
To make it as easy as possible to get started with Java on the Raspberry Pi to interact with electronic components, I started a new section on the Pi4J website with JBang examples.
In this tutorial, I want to show you how you can read the temperature, humidity, and pressure from a BME280 Sensor.
Came back from vacation, started working on the neck but realised I really needed more tools. Luckily, I could get some that weren’t too expensive.
Once upon a time, a remote controlled (RC) car was something you’d buy at Radio Shack or your local hobby store. These days, you can print your own, complete with suspension, right at home, as this project from [Logan57] demonstrates.
While I don’t care too much about ideas and projects that I believe to be dead ends or maybe even doomed to fail eventually, a recent interaction on Superhighway84 got me to write down a few thoughts on why I believe Project Gemini is a really bad idea.
Therefore, in an attempt to make an inclusive solution (rather than exclusive, as Marius thought of Gemini), I suggest a new browser, namely the Small Web Browser, with the following design requirements: [...]
Welcome. Due to some annoying regressions in the previous release we think we owned it to everyone to do a quick patch follow-up.
HTTP Strict Transport Security (HSTS) is a way to signal to a web client that valid HTTPS certificates must be used when connecting to a domain. There are two main benefits to HSTS.
First, it prevents a user from connecting over an unencrypted HTTP connection. Unencrypted HTTP leaks data to the network and is vulnerable to manipulation in man-in-the-middle attacks.
Second, it prevents a user from connecting if the server presents an untrusted TLS certificate. Users aren’t great at deciding if a warning message about an untrusted TLS certificate is a security concern or just a misconfiguration. They don’t have the knowledge or tools to decide, and they may inadvertently allow an attack to proceed by clicking through the warning.
In a previous post, I observed that the classic way to compute round-trip time (RTT) statistics and retransmission timers does not work well. When acknowledgements are too frequent, the correlation between successive RTT measurements causes the smoothed RTT estimate to track closely the last values, and the RTT variations to be widely underestimated.
This imprecision impacts both the effectiveness of loss recovery and the implementation of delay-based congestion algorithms like BBR. I think this can be fixed by updating the variables just ‘once per RTT’. In this post, I first describe the once per RTT update algorithm, then report on promising measurements using the simulations in the Picoquic test suite.
Tor Browser 13.0a1 is now available from the Tor Browser download page and also from our distribution directory.
This release updates Firefox to 115.2.0esr, including bug fixes, stability improvements and important security updates. This is a Desktop platform only release (Windows, macOS, and Linux), but Android should be available in the coming weeks.
We previously discussed in our webinar The Case for OS Diversity and Independence the great deal of value, security, and flexibility to be gained from using a diversity of operating systems. To help make implementation such diversity possible, Klara has produced a set of articles that discuss the differences between Linux and FreeBSD across various subsystems. These articles aim to act as a sort of Rosetta Stone, helping experienced administrators and developers turn their skills with one of the operating systems into knowledge of the other. With summer upon us, now is a great time to read through this series and learn how you can take maximum advantage of OS diversity.
GUADEC 2023 is underway in Riga. It’s great to see people face to face after a long time. Kicked off the first day with an ADHD trip of a talk. Rather than putting links in my slides, where nobody has the chance of actually follow, I’ve assembled them here. Enjoy!
The Internet does not forget? The opposite is the case. Huge mountains of data are lost on the internet every day. That’s why the Archive Team scours the vastness of the WWW and rescues data from extinction – around the clock and on a voluntary basis.
This is the first of a (hopefully) series of posts about Nix. Disclaimer: I’m a
super beginner with Nix. So this series of blog posts is more akin to notes that
I’m taking while learning than a super detailed tutorial. So if you’re a Nix
Fallback is a risk mitigation strategy for reducing the negative impact of failures in a cost-effective manner.
Where failover uses the same type of solution to achieve the same outcome, fallback uses a different type of solution to maintain the essential system functionality.
Hopefully, at the end of this year of experimentation, I’ll be a bit closer to figuring out what I want to do professionally. Do I want to really focus on something new like Python or Go? Do I want to lean into Java more? Or possibly do I even try and stay working on as many technologies as I can?
Choosing to use a block range index (BRIN) to query a field with high correlation is a no-brainer for the optimizer. The small size of the index and the field's correlation makes BRIN an ideal choice. However, a recent event taught us that correlation can be misleading. Under some easily reproducible circumstances, a BRIN index can result in significantly slower execution even when the indexed field has very high correlation.
The advantages of the Rust programming language are generally well-known; memory safety is a feature that has attracted a lot of developer attention over the last few years. At the inaugural Embedded Open Source Summit (EOSS), which is an umbrella event for numerous embedded-related conferences, Martin Mosler presented on using Rust for an embedded project. In the talk, he showed how easy it is to get up and running with a Rust-based application on a RISC-V-based development board.
Mosler works for Zühlke Engineering in Switzerland; both he and his company see the potential of Rust for new development, particularly for embedded projects. That is why the company supports his community work on Rust, including holding Rust meet-ups and traveling to Prague to attend EOSS and give the talk. He is building up Rust knowledge within the company so that it is available for new projects as they arise.
