UNIX FILE SYSTEM

1/23/98

Unix File System: The Unix file system consists of a series of inodes each of which describes one file. Each inode contains the size, owner, read\write permissions, link counts, other security data, and pointers to disk blocks containing parts of the file. Unix has 10 user accessible attributes - Directory and read-write-execute permission for the user, the user's group, and others. Large files may be chained through "indirect" blocks of pointers. Directories are simply files that contain file names (case sensitive) and pointers to the inodes for the files.

The Unix file system is somewhat similar to NTFS, but data is not treated as an attribute, so each inode must point to a data block elsewhere on the disk. Unix file systems can become fragmented and defragmentation utilities exist. Like HPFS, Unix does deferred writes and must be shut down properly in order to clear all operations in the queue. Like HPFS and unlike NTFS, recovery from a crashed file write can be quite time consuming as integrity of the entire file system must be checked.

Return To Index Copyright 1994-2002 by Donald Kenney.