FreeBSD’s filesystem, the Unix File System (UFS), is a direct descendant of the filesystem shipped with BSD 4.4. One of the original UFS authors still develops the FreeBSD filesystem and has added many nifty features in recent years. FreeBSD is not the only operating system to still use the 4.4 BSD filesystem or a descendant thereof. A Unix vendor that doesn’t specifically tout its “improved and advanced” filesystem is probably running a UFS derivative.

UFS’s place as the primordial filesystem has given it leave to extend tendrils throughout FreeBSD. Many UFS concepts underlie FreeBSD’s support for other filesystems, from ...

Get Absolute FreeBSD, 3rd Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.