(1) To make a
file or other piece of
data inaccessible.
File locking is a critical component of all
multi-user computer systems, including
local-area networks. When
users share files, the
operating system must ensure that two or more users do not attempt to modify the same file simultaneously. It does this by
locking the file as soon as the first user
opens it. All subsequent users may
read the file, but they cannot write to it until the first user is finished.
In addition to file locking, many database management systems support record locking, in which a single record, rather than an entire file, is locked. This enables different users to access different records within the same file without interfering with one another.
(2) In Macintosh environments, locking a diskette means write-protecting it.
