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Kernel: POSIX Experiment, Linux Dial, and EXT4 Performance
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University of Toronto ☛ In POSIX, you can theoretically use inode zero
Since I'm the sort of person that I am, this made me wonder if you could legally use inode zero today in a POSIX compliant system. The Single Unix Specification, which is more or less POSIX, sets out that ino_t is some unsigned integer type, but it doesn't constrain its value. Instead, inode numbers are simply called the 'file serial number' in places like sys/stat.h and dirent.h, and the stat() family of functions, readdir() and posix_getdents() don't put any restrictions on the inode numbers except that st_dev and st_ino together uniquely identify a file. In the normal way to read standards, anything not explicitly commented on is allowed, so you're allowed to return a zero for the inode value in these things (provided that there is only one per st_dev, or at least that all of them are the same file, hardlinked together).
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Hackaday ☛ What Does Linux Need? A Dial!
It’s fair to say that there can’t be many developers who have found the need for a rotary telephone dial as a peripheral for their Linux computer, but in case you are among them you might find [Stefan Wiehler]’s kernel driver for rotary dials to be of use.
It’s aimed at platforms such as systems-on-chip that have ready access to extra GPIOs, of which it will need a couple to service the BUSY and PULSE lines. There are full set-up instructions, and once it’s in place and configured it presents the dial as though it were a number pad.
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Web Pro News ☛ EXT4 Performance Soars with Linux 6.16 Update
In the ever-evolving world of Linux kernel development, the EXT4 filesystem, a stalwart of stability and reliability, has received a remarkable performance boost with the upcoming Linux 6.16 release.
The update, detailed in recent kernel patch submissions, introduces a transformative change to how EXT4 handles specific workloads, promising what developers describe as “really stupendous performance” gains. As reported by Phoronix, this enhancement could redefine expectations for one of the most widely used filesystems in the Linux ecosystem.
The driving force behind this optimization is Ted Ts’o, a veteran kernel developer and maintainer of EXT4, who submitted the changes for Linux 6.16 on May 27, 2025. According to a message posted on the Linux Kernel Mailing List, Ts’o outlined a patch that addresses long-standing inefficiencies in EXT4’s handling of certain file operations. The specific focus is on optimizing the filesystem’s behavior under heavy write workloads with delayed allocation, a technique that postpones block allocation until data is flushed to disk, often leading to fragmentation and performance bottlenecks.