Language Selection

English French German Italian Portuguese Spanish

today's leftovers

Filed under
Misc
  • Fedora 34 Looking To Tweak Default zRAM Configuration

    ast year with Fedora 33 zRAM was switched on by default. The setup was that using a compressed zRAM drive for swap space leads to better performance and in turn a better user experience. Some spins of Fedora have been using swap-on-zRAM by default going back many releases while since F33 it's been used for all spins. Now with Fedora 34 the configuration is being further refined.

    With Fedora 33, the zRAM configuration was limited to a 0.5 fraction of RAM or 4GB, whichever is smaller, while for Fedora 34 the zram-fraction will be 1.0 and the maximum zRAM size set to 8GiB.

    [...]

    This in particular should help the Fedora 34 experience for systems with minimal amounts of RAM.

  • A Zoological guide to kernel data structures

    Recently I was working on a BPF feature which aimed to provide a mechanism to display any kernel data structure for debugging purposes. As part of that effort, I wondered what the limits are. How big is the biggest kernel data structure? What's the typical kernel data structure size?

    [...]

    A lot of the articles we read about the Linux kernel talk about size, but in the context of numbers of lines of code, files, commits and so on. These are interesting metrics, but here we're going to focus on data structures, and we're going to use two fantastic tools in our investigation...

    [...]

    Zooming out again, what's interesting about the pattern of structure size frequency is that it seems to reflect the inherent cost of large data structures; they pay a tax in terms of memory utilization, so while we see many small data structures, and the falloff as we approach larger sizes is considerable.

    This pattern is observed elsewhere, bringing us back to the zoological title of this post. If we look at the frequency of animal species grouped by their size, we see a similar pattern of exponential decay as we move from smaller to larger species sizes. For more info see https://en.wikipedia.org/wiki/Body_size_and_species_richness. If metabolic cost is a factor in determining this pattern in nature, we can observe a similar "metabolic cost" in memory utilization for larger data structures in the Linux kernel also. A related observation - that smaller species (such as insects) exist in much larger numbers than larger species in nature - would be interesting to investigate for the Linux kernel, but that would require observing data structure utilization in running systems, which is a job for another day!

  • Destination Linux 208: Mythbusting Linux Misconceptions

    This week on Destination Linux, we’re going to bust some myths as we talk about some Linux Misconceptions. Then we’re going to review some information on openSUSE and review the interesting facts revealed in it’s most recent community poll. We’ve also got our famous tips, tricks and software picks. All of this and so much more this week on Destination Linux.

  • Software Is Eating Every Layer Of The Datacenter

    Software may be eating the world, as Marc Andreessen correctly asserted nearly a decade ago, but some parts of the world are crunchier than others and take some time for the hardware to be smashed open and for software to flow in and out of it.

    We have been watching with great interest since around 2008 or so as merchant silicon came to switching and routing and how control of hardware was broken free from control of software, much as the X86 platform emerged as a common computing substrate a decade earlier. Initial attempts at creating portable and compatible operating systems for switching and routing had their issues, but a second wave network operating systems are emerging and, we think, will eventually become the way that networking is done in the datacenter, breaking the hegemony of proprietary operating systems as happened in compute in the past. A decade of open systems Unix platforms on dozens of chip architectures really just helped create the conditions that allowed Linux on X86 to become the dominate platform in the datacenter. And, ironically, now that Linux dominates, now different hardware, now including various kinds of accelerators as well as new CPUs, can now be slipped easily in and out of compute in the datacenter without huge disruption to Linux.

    The same thing is starting to happen with network operating systems, including the SONiC/SAI effort championed by Microsoft, the ArcOS platform from Arrcus, whatever Nvidia ultimately cooks up through the combination of Mellanox Technology and Cumulus Networks. Cisco Systems is now a supplier of merchant silicon with its Silicon One router chips, which debuted in December 2019 and which were augmented with switch chips last October. Every switch ASIC vendor has created some form of programmability for its packet processing engines, with P4 as advanced by Barefoot Networks (now part of Intel) being the darling but by no means the only way to achieve programmability, and now we see the industry rallying behind the concept of the Data Processing Unit, or DPU, which among other things manages network and storage virtualization and increasingly runs the compute hypervisor, offloading these functions from the CPUs in host systems.

  • The Fridge: Ubuntu Weekly Newsletter Issue 665

    Welcome to the Ubuntu Weekly Newsletter, Issue 665 for the week of January 3 – 9, 2021.

  • The 2020 CC Global Summit Keynotes Are Here!

    In addition to the 170+ sessions hosted at last year’s virtual event, we hosted three keynotes that helped us think through how to connect the events of 2020 with our work—and find a path forward in hope and optimism. We’re excited to share these recordings of the keynotes with you today!

  • Wikipedia’s future lies in poorer countries

    The number of people actively editing Wikipedia articles in English, its most-used language, peaked in 2007 at 53,000, before starting a decade-long decline. That trend spawned fears that the site would atrophy into irrelevance. Fortunately for Wikipedia’s millions of readers, the bleeding has stopped: since 2015 there have been around 32,000 active English-language editors. This stabilising trend is similar for other languages of European origin.

    Meanwhile, as more people in poorer countries gain [Internet] access, Wikipedia is becoming a truly global resource. The encyclopedia’s sub-sites are organised by language, not by nationality. However, you can estimate the typical wealth of speakers of each language by averaging the GDP per head of the countries they live in, weighted by the number of speakers in each country. (For Portuguese, this would be 80% Brazil, 5% Portugal and 15% other countries; for Icelandic, it is almost entirely Iceland.)

More in Tux Machines

Proprietary Software and Digital Restrictions (DRM)

  • GitHub still won’t explain if it fired someone for saying ‘Nazi,’ and employees are pissed

    The current conflict began the day of the riots in Washington, DC when a Jewish employee told co-workers: “stay safe homies, nazis are about.” Some colleagues took offense to the language, although neo-Nazi organizations were, in fact, present at the riots. One engineer responded: “This is untasteful conduct for workplace [in my opinion], people have the right to protest period.”

  • Amazon Web Services opens first office in Greece

    It said services covered areas from big data analytics and mobile, web and social media applications to enterprise business applications and the internet of things.

  • Critical Microsoft Defender Bug Actively Exploited; Patch Tuesday Offers 83 Fixes

    Researchers believe the vulnerability, tracked as CVE-2021-1647, has been exploited for the past three months and was leveraged by hackers as part of the massive SolarWinds attack. Last month, Microsoft said state-sponsored hackers had compromised its internal network and leveraged additional Microsoft products to conduct further attacks.

    Affected versions of Microsoft Malware Protection Engine range from 1.1.17600.5 to 1.1.17700.4 running on Windows 10, Windows 7 and 2004 Windows Server, according to the security bulletin.

  • Making Clouds Rain :: Remote Code Execution in Microsoft Office 365

    TL;DR; This post is a story on how I found and exploited CVE-2020-168751, a remote code execution vulnerability in Exchange Online and bypassed two different patches for the vulnerability. Exchange Online is part of the Office 365 suite that impacted multiple cloud servers operated by Microsoft that could have resulted in the access to millions of corporate email accounts.

  • Dropbox lays off 11% of its workforce as COO departs

    Dropbox in November provided revenue guidance of $497 million to $499 million for the fourth quarter. The company said at the time that it’s aiming to achieve margins of 28% to 30% in the long term.

  • Technical Error 'Saw 150,000 U.K. Police Records Wiped' From Databases

    Police have been asked to assess if there is a threat to public safety after it was revealed that thousands of police records were deleted in error, including data on fingerprints, DNA, and arrest histories.

    The error, first reported in the Times, saw 150,000 files lost, with fears it could mean offenders go free. A coding error is thought to have caused the earmarking of the files for deletion.

    The U.K. Home Office said the lost entries related to people who were arrested and then released without further action and no records of criminal or dangerous people had been deleted. Home secretary Priti Patel is now under pressure to explain the mistake, which the opposition Labour party said "presents huge dangers" for public safety.

  • January 2021 Linux Foundation Newsletter: Bootcamp Sale, SolarWinds Orion, New Kubernetes & WebAssembly Classes, LFX Webinar Series
  • How I hijacked the top-level domain of a sovereign state

    Note: This issue has been resolved and the .cd ccTLD no longer sends NS delegations to the compromised domain.

    TL;DR: Imagine what could happen if the country-code top-level domain (ccTLD) of a sovereign state fell into the wrong hands. Here’s how I (@Almroot) bought the domain name used in the NS delegations for the ccTLD of the Democratic Republic of Congo (.cd) and temporarily took over 50% of all DNS traffic for the TLD that could have been exploited for MITM or other abuse.

  • Apple begins blocking M1 Mac users from side loading iPhone and iPad applications

    As a refresher, Apple Silicon Macs allow users to run iOS and iPad applications on their Mac, but developers can opt out of allowing their apps to be installed on the Mac. This is the path that many developers have taken, making the necessary change in App Store Connect to remove their app from the Mac App Store.

    But with that being said, until today, you could manually install iOS apps like Netflix, Instagram, and Facebook on an M1 Mac by using their respective IPA files downloaded under a valid Apple ID. Many people were using tools such as iMazing to complete this process.

    9to5Mac has now confirmed that, starting today, this is no longer possible unless the application is available on the Mac App Store. Apple has flipped the necessary sever-side switch to block iPhone and iPad applications from being installed on Apple Silicon Macs.

  • Apple is blocking Apple Silicon Mac users from sideloading iPhone apps

    Apple has turned off users’ ability to unofficially install iOS apps onto their M1 Macs (via 9to5Mac). While iOS apps are still available in the Mac App Store, many apps, such as Dark Sky and Netflix, don’t have their developer’s approval to be run on macOS. Up until now, there was a workaround that allowed the use of third-party software to install the apps without having to use the Mac App Store, but it seems like Apple has remotely disabled it.

    When we tried to install an unsupported app on an M1 Mac running macOS 11.1, we got an error message saying that we couldn’t install it and should “try again later”. You can see a screenshot at the top of this article.

  • Apple TV Plus Free Subscriptions Extended Again, This Time Through July 2021

    The tech giant is extending the free-access period for Apple TV Plus customers who have signed up through its 12-month free subscription offer through July 2021. That’s after it had previously pushed that gratis period to February. So if you were among the first to take the one-year-free deal back in November 2019, that’s turned into 21 months free of Apple TV Plus.

  • Spotify Enters Settlement Talks With PRO Music Rights Founder Jake P. Noch

    But a new legal filing, shared with DMN this afternoon, reveals that Spotify and Noch have officially entered settlement talks. The involved parties “jointly” moved for a 60-day stay, “including discovery and all deadlines,” so that they can “attempt to negotiate a resolution of this matter,” the three-page-long document (dated January 13th, 2021) indicates.

    Furthermore, the filing specifies that Sosa Entertainment, Jake P. Noch, and Spotify “have recently made progress towards a potential resolution of the litigation.” The joint motion doesn’t elaborate upon the terms of this possible agreement – though Noch said in a statement that he’s eager to begin working towards an “excellent resolution” in earnest.

  • The FSF fights for your right to repair

    It is this example of automated vehicles that served as inspiration for the FSF's animated video Fight to Repair.

    However, any technology we use could potentially be co-opted by the proprietary, DRM-controlled subscription model Tesla and the tractor manufacturers are proposing. Imagine your "smart home" having a broken lock, or worse, being broken into, and not having the control, or the simple right to repair the bug. Countless other examples can be found showing us that the key to a free future is the right to repair. We need to fight for a future in which the software used is free in order to maintain ownership and control not only over our technology, but over our lives.

Debian Developers: Christian Kastner, Junichi Uekawa, and Michael Prokop

  • Christian Kastner: Keeping your Workstation Silent

    I've tried numerous coolers in the past, some of monstrous proportions (always thinking that more mass must be better, and reputable brands are equally good), but I was never really satisfied; hence, I was doubtful that trying yet another cooler would make a difference. I'm glad I tried the Noctua NH-D15 anyway. With some tweaking to the fan profile in the BIOS, it's totally inaudible at normal to medium workloads, and just a very gentle hum at full load—subtle enough to disappear in the background. For the past decade, I've also regularly purchased sound-proofed cases, but this habit appears anachronistic now. Years ago, sound-proofed cases helped contain the noise of a few HDDs. However, all of my boxes now contain NVMe drives (which, to me, are the biggest improvement to computing since CPUs going multi-core). On the other hand, some of my boxes now contain powerful GPUs used for GPGPU computing, and with the recent higher-end Nvidia and AMD cards all pulling in over 300W, there is a lot of heat to manage. The best way to quickly dump heat is with good airflow. Sound-proofing works against that. Its insulation restricts airflow, which ultimately causes even more noise, as the GPU's fans need to spin at very high RPMs. This is, of course, totally obvious in hindsight.

  • Junichi Uekawa: It's been 20 years since I became a Debian Developer.

    It's been 20 years since I became a Debian Developer. Lots of fun things happened, and I think fondly of the team. I am no longer active for the past 10 years due to family reasons, and it's surprising that I have been inactive for that long. I still use Debian, and I still participate in the local Debian meetings.

  • Michael Prokop: Revisiting 2020

    Mainly to recall what happened last year and to give thoughts and plan for the upcoming year(s) I’m once again revisiting my previous year (previous editions: 2019, 2018, 2017, 2016, 2015, 2014, 2013 + 2012). Due to the Coronavirus disease (COVID-19) pandemic, 2020 was special™ for several reasons, but overall I consider myself and my family privileged and am very grateful for that. In terms of IT events, I planned to attend Grazer Linuxdays and DebConf in Haifa/Israel. Sadly Grazer Linuxdays didn’t take place at all, and DebConf took place online instead (which I didn’t really participate in for several reasons). I took part in the well organized DENOG12 + ATNOG 2020/1 online meetings. I still organize our monthly Security Treff Graz (STG) meetups, and for half of the year, those meetings took place online (which worked OK-ish overall IMO). Only at the beginning of 2020, I managed to play Badminton (still playing in the highest available training class (in german: “Kader”) at the University of Graz / Universitäts-Sportinstitut, USI). For the rest of the year – except for ~2 weeks in October or so – the sessions couldn’t occur. Plenty of concerts I planned to attend were cancelled for obvious reasons, including the ones I would have played myself. But I managed to attend Jazz Redoute 2020 – Dom im Berg, Martin Grubinger in Musikverein Graz and Emiliano Sampaio’s Mega Mereneu Project at WIST Moserhofgasse (all before the corona situation kicked in). The concert from Tonč Feinig & RTV Slovenia Big Band occurred under strict regulations in Summer. At the beginning of 2020, I also visited Literaturshow “Roboter mit Senf” at Literaturhaus Graz.

Games: Familiars.io, Valve and Godot

  • Familiars.io is a MMO monster catching game where the creatures have permadeath

    Well this is quite unusual. You've played monster catching games before but not like this. Familiars.io put a fresh spin on it all and it's quite ingenious. Developed as a pixel-art retro-looking browser game, it's super accessible since you can play it on pretty much anything that can run some simple graphics in a browser window. It's an MMO too, so you can join up with others and chill out. When you want to, go off and catch some monsters, engage is some PvP and perhaps find a new favourite game waiting for you.

  • What we expect to come from Valve to help Linux gaming in 2021 | GamingOnLinux

    By now you've probably heard either through us in our previous article or elsewhere that Valve are cooking something up to help Linux gaming even further. We have an idea on what one part of it is. Valve already do quite a lot. There's the Steam Play Proton compatibility layer, the new container runtime feature to have Linux games both natively supported and Windows games in Proton run through a contained system to ensure compatibility, their work on Mesa drivers and much more. In Valve's review of Steam in 2020 that we covered in the link above, one thing caught our eye and has been gaining attention. Valve mentioned for 2021 they will be "putting together new ways for prospective users to get into Linux gaming and experience these improvements" so what exactly does that mean? Well, a big part of that might have already been suggested directly.

  • Godot Engine - Dev snapshot: Godot 3.2.4 beta 6

    While our main focus stays on the 4.0 branch, the current stable 3.2 branch is receiving a lot of great improvements, and the upcoming 3.2.4 release is going to be packed with many new features.

Zeroshell 3.9.5 Released

Zeroshell 3.9.5 is ready. In this release TLS 1.0 has been disabled and TLS 1.2 enabled for HTTPS. This improves security and compatibility with new browser releases. Read more