1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.roff% 5.\" 6.\" @(#)update.8 8.3 (Berkeley) 04/19/94 7.\" 8.Dd 9.Dt UPDATE 8 10.Os 11.Sh NAME 12.Nm update 13.Nd flush internal filesystem caches to disk frequently 14.Sh SYNOPSIS 15.Nm update 16.Sh DESCRIPTION 17The 18.Nm update 19command helps protect the integrity of disk volumes 20by flushing 21volatile cached filesystem data 22to disk at thirty second intervals. 23.Nm Update 24uses the 25.Xr sync 2 26function call to do the task. 27.Pp 28.Nm Update 29is commonly invoked at startup time by 30.Xr rc 8 31when the system goes multi-user. 32.Sh SEE ALSO 33.Xr sync 2 , 34.Xr fsck 8 , 35.Xr init 8 , 36.Xr rc 8 , 37.Xr sync 8 38.Sh BUGS 39It is possible on some systems that a 40.Xr sync 41occurring simultaneously with a crash may cause 42file system damage. See 43.Xr fsck 8 . 44.Sh HISTORY 45An 46.Nm update 47command appeared in 48.At v6 . 49