.\" Copyright (c) 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" %sccs.include.redist.roff%
.\"
.\"	@(#)update.8	8.2 (Berkeley) 12/11/93
.\"
.Dd 
.Dt UPDATE 8
.Os
.Sh NAME
.Nm update
.Nd flush internal filesystem caches to disk frequently
.Sh SYNOPSIS
.Nm update
.Sh DESCRIPTION
The
.Nm update
command helps protect the integrity of disk volumes
by flushing
volatile cached filesystem data
to disk at thirty second intervals.
.Nm Update
uses the
.Xr sync 2
function call to do the task.
.Pp
.Nm Update
is commonly invoked at startup time by
.Xr rc 8
when the system goes multi-user.
.Sh SEE ALSO
.Xr sync 2 ,
.Xr fsck 8 ,
.Xr init 8 ,
.Xr rc 8 ,
.Xr sync 8
.Sh BUGS
It is possible on some systems that a
.Xr sync
occuring simultaneously with a crash may cause
file system damage. See
.Xr fsck 8 .
.Sh HISTORY
An
.Nm update
command appeared in
.At v6 .