UNIX File System

The UNIX File System (UFS) is compatible with the Berkeley 4.3 Tahoe release. UFS allows a pathname component to be 255 bytes, with the fully qualified pathname length restriction of 1023 bytes. The Digital UNIX Version 4.0 implementation of UFS supports file sizes which exceed 2 GBs.

Digital added support for file block clustering which provides sequential read and write access that is equivalent to the raw device speed of the disk and up to a 300% performance increase over previous releases of the operating system; file-on-file mounting (FFM) for STREAMS; and integrated UFS with the Unified Buffer Cache. UFS also supports Extended File Attributes (XFAs). For more information on XFAs, see the section called Virtual File System.