which #filesystems support #reflinks: on #Linux, Bcachefs, btrfs, XFS, OCFS2, but not OpenZFS; on FreeBSD, neither OpenZFS nor #ZFS; on Solaris, ZFS (with cp -z); on MacOS, APFS (which Apple is switching to; with cp -c or the clonefile system call), and on Microsoft Windows, NTFS and DUPLICATE_EXTENTS_TO_FILE.
#Apple broke #Asahi #Linux booting on the #Macintosh with the new macOS beta, but apparently this will be fixed according to some #Mastodon account
on 02026-06-11#Linux without an #MMU such as #ucLinux
on 02026-06-07#Linux supported the #68K in 02000
on 02026-05-31The Mate #Linux desktop environment.
on 02026-04-30prevent #Linux from loading any modules after boot time for some #security hardening, including against #copy-fail
on 02026-04-30Today’s #security hole in #Linux, a local root, discovered in an hour with #AI, called #copy-fail.
on 02026-04-29#Linux is losing #AX.25, #PCMCIA Ethernet, etc., to reduce #security exposure due to #AI
on 02026-04-22discussion of Kent Overstreet’s temporary ban from contributing to #Linux. #bcachefs #history
on 02026-04-10#news summarizing #Trump #politics concerns driving #France to #Linux: “Since taking office in January 2025, Trump has upped his attacks on world leaders — straight-out capturing one and aiding in the killing of another. He has also weaponized sanctions against his critics, who include judges on the International Criminal Court, effectively cutting them off from transacting with U.S. companies. Those who have been sanctioned have reported having their bank accounts closed and access to U.S. tech services terminated, as well as being blocked from any other U.S. service.”
on 02026-04-10how Assistant Professor Kangjie Lu and his grad students Aditya Pakki and Qiushi Wu got the University of Minnesota banned from contributing to #Linux in 02021. #history
on 02026-01-13Ed Trager’s old notes from #Unifont about getting #Unicode working in #Linux and #Unix, from the Fribidi days. #documentation
on 02025-12-14#zram vs. #zswap in #Linux. #toread
on 02025-11-05using #zram vs. #zswap to get better UI #latency in #Linux. #Fedora eliminated disk-based swap by default. #toread
on 02025-11-05running #Linux on #CHERI for #security #toread
on 02025-11-05state of embedded #Linux #electronics #hardware
on 02025-11-05#object-orientation in #C in the #Linux kernel and in #OSDev in general #toread
on 02025-08-27#Treacherous-Computing for “confidential VMs” #privacy despite #Linux #virtualization #toread
on 02025-08-24#Secure-Boot stops working on #Linux in September because #Microsoft’s signature on "shim" expires
on 02025-07-20#Linux isn’t fully usable yet on #Snapdragon X Elite systems; it can boot, display, and do WiFi, but HDMI, the USB-A ports, and sound are broken
on 02025-03-28The #Linux kernel mailing list thread removing Russian maintainers due to #USA #politics and the #Ukraine invasion. Will Russia and China fork Linux? #LKML
on 02024-10-25to flush the instruction cache for #RTCG JIT #compilers on #ARM #Linux you need to make sure the memory is mapped with PROT_EXEC before you invoke sys_cacheflush or __clear_cache(). #hardware
Here’s how the #Linux kernel generates stack backtraces on #RISC-V by walking a chain of stack frames linked by frame pointers. With alloca() and variable-length arrays, the stack pointer alone isn’t enough to find your local variables.
on 02023-09-02#Android #AOSP #ARM #asm for #Linux system calls
on 02023-07-19#Linux #ARM system call interface (for #EABI), with a table of system calls and arguments. #asm
on 02023-07-19In #Linux on #ARM in #EABI, the system call arguments are in registers r0-r6, and the return value is in registers r0 and r1. #asm
on 02023-07-19Since #Linux 2.6, #ARM system calls under the #EABI use the swi 0 or svc 0 instruction with the system call number in R7 and arguments in r0-r5, with 64-bit arguments starting in an even register. #asm
The so-called #ARM #EABI is the standard ABI for #Linux, supplanting the so-called OABI. Explains how system calls work in #asm. Also explains the checkered history of interworking. Debian architecture “armel” is EABI, “arm” is OABI, dropped in Squeeze.
on 02023-07-19#Postgres (and probably other #databases) had a big bug with #fsync on #Linux (and OpenBSD and NetBSD) in 02018 (and for many years before that): disk write errors (usually caused by USB drive hotunplug) would discard the data that failed to be written and never report the error, even on fsync(), though since kernel 4.13 the error is only lost if the file is closed by the writer and reopened before calling fsync(). So Postgres, and I guess anything else that cares about recovering from I/O errors, has to move to direct I/O (DIO), which seems to mean O_DIRECT. dmsetup has error and flakey targets to simulate disk errors.
#history of how Linus debugged the earliest versions of #Linux, using an infinite loop to provide one bit of information about how far the boot process had gotten
on 02022-12-28#PostmarketOS #Linux supports the #Redmi-2 chip #MSM8916 except for the camera
on 02022-02-09The #XFS #filesystem on #Linux has supported #reflinks since about 02016 (XFS 4.9), and btrfs for longer.
on 02021-11-11"reflinks" allow you to make a copy-on-write link to a file snapshot; now supported both on #Linux (cp --reflink) and #MacOS (cp -c). Not supported by ext4fs I think. #filesystem
“A #filesystem “change journal” and other topics” (in support of, e.g., backups) #Linux
on 02021-11-11Why #RISC-V doesn’t yet support #KVM; looks like #Linux will change some RISC-V policies
on 02021-05-29notes from 02009 on #tracing with #Linux tracepoints, including the use of #perf. On Ubuntu you need to install, for example, linux-tools-5.8.0-40-generic if you’re running linux-image-5.8.0-40-generic.
on 02021-02-03how to use #Linux kernel #tracing tracepoints effectively and analyze #performance with #perf
on 02021-02-03how to define #Linux kernel #tracing tracepoints
on 02021-02-03how to use #Linux kernel #tracing tracepoints
on 02021-02-03#Linux on #AVR #hardware by running #ARM #emulation ("μARM") in the AVR, achieving about 0.01 MIPS
on 02021-01-24a GCC bug that freed a stack frame one instruction before returning a value allowed interrupts to sometimes panic #Linux on ARM when compiled in 02021 with GCC 4.9.4 from 02014. So now you have to compile Linux with GCC 5.1. #facepalm
on 02021-01-24Firecracker lets you start up VMs in under 125 ms using #KVM, but #Linux then takes 2–3 seconds to run systemd. DigitalOcean does support nested #virtualization. #emulation
on 02021-01-24#fsync on #Linux and other Unixes can fail, which indicates not that your data hasn’t been written yet but that it’s actually been lost entirely. There’s no interface to tell which data and thus no reasonable way to retry, except that you can reread the data you tried to write to see which data is wrong.
on 02019-02-11How different #Linux #kernels did context switch on i386 and amd64.
on 02019-02-01#PDF #paper on #futexes and #concurrency in #Linux
on 02017-11-25Nicolas Perriault switched back to #Linux after 10 years on #MacOS now that #Apple is kind of sucking
on 02017-01-14Short #introduction to how virtual memory works, mostly for novices but also explaining why strict overcommit works so poorly in #Linux
on 02016-10-10Linaro and #ARM working on #Linux scheduler power saving
on 02016-10-07CRIU implements checkpoint-and-restore functionality for #Linux in userspace. It works as long as your tasks aren’t running under a debugger, don’t have device files open, aren’t running in i386 mode on an amd64 platform, aren’t using X11 (!!), aren’t using sockets “other than TCP, UDP, UNIX, packet and netlink”, or a couple of other things. The #checkpointing facilities it needs are integrated into the mainline kernel since 3.11.
on 02016-08-01In 2014, the #XKEYSCORE code was published, including their list of “extremist forums”, which apparently includes #Linux Journal. #security #privacy #human-rights #NSA
on 02016-06-26State of #Linux on the desktop.
on 02016-01-02Drepper explains how to #JIT in #Linux.
on 02015-11-16Nested uid/gid namespaces since #Linux 3.8 to enable #security #virtualization of users and groups! The uid namespace can map users arbitrarily to outside-namespace uids. Not sure if you can invent new uids. Unfortunately, since #Red-Hat doesn’t trust new features, they’re going to make this useless in RHEL for a while, but Fedora is enabling it.
on 02015-08-11“How to print out #Java compiled #asm instructions on #Linux/MacOS” by installing #hsdis (for #performance mostly).
on 02015-08-10More about how to read and write #HFS+ filesystems on #Linux.
on 02015-08-10How to mount #HFS+ filesystems on #Linux safely by turning off journaling on #MacOS.
on 02015-08-10The history of the 2000–1 #dnotify and 2005 #inotify filesystem event APIs in the #Linux kernel. #LWN
on 02015-08-10