U

UFS snapshot

A backing store image (fancy term for an image used as a backup) of a file system at a given point in time.

umask

A value that modifies the default permissions on a newly created file or directory, resulting in the file or directory's real permission structure.

Universal Disk Format (UDF)

The file system used for DVD-ROMs.

UNIX File System (UFS)

The standard hard disk-based file system used in Solaris (and most of the rest of the UNIX world).

unmount

To make a file system unavailable for use.

User ID (UID)

A number that uniquely identifies a user on the computer.

username

A character string that uniquely identifies a user on the computer. Users log in by using their username and a password.

user profile

A set of files run during the login process that configures the user's working environment.