DESCRIPTION

     The update command helps protect the integrity of disk volumes by flush-
     ing volatile cached filesystem data to disk at thirty second intervals.
     Update uses the sync(2) function call to do the task.  The normal_inter-
     val and save_energy_interval can be used to set the sync(2) interval in
     seconds of the normal case and the case where the computer is trying to
     save energy.

     Update is commonly invoked at startup time by rc(8) when the system goes
     multi-user.

SEE ALSO

     sync(2), fsck(8), init(8), rc(8), sync(8)

BUGS

     It is possible on some systems that a sync occurring simultaneously with
     a crash may cause file system damage. See fsck(8).

HISTORY

     An update command appeared in Version 6 AT&T UNIX.

BSD                             April 19, 1994                             BSD