https://slow-is-smooth.io/tags/kernel/Recent content in Kernel on Shai AsherHugoen-gbSat, 31 Oct 2026 09:30:00 +0200https://slow-is-smooth.io/blog/the-fat-sector-that-was-written-256-times/Sat, 31 Oct 2026 09:30:00 +0200https://slow-is-smooth.io/blog/the-fat-sector-that-was-written-256-times/<p>On a FAT32 volume mounted <code>-o sync</code>, asking Linux to reserve 16 MiB for each of sixteen files used to take twelve and a half minutes. With three small patches merged for Linux 7.4, the same request takes three and a half seconds. The disk did not get faster, and no instruction got cheaper. The kernel just stopped writing the same 512-byte sector to the disk 256 times in a row.</p>