1.\" @(#)update.8 6.2 (Berkeley) 6/24/90 2.\" 3.\" %sccs.include.redist.man% 4.\" 5.\" @(#)update.8 6.3 (Berkeley) 03/16/91 6.\" 7.Dd 8.Dt UPDATE 8 9.Os ATT 7th 10.Sh NAME 11.Nm update 12.Nd flush internal filesystem caches to disk frequently 13.Sh SYNOPSIS 14.Nm update 15.Sh DESCRIPTION 16The 17.Nm update 18command helps protect the integrity of disk volumes 19by flushing 20voliatile cached filesystem data 21to disk at thirty second intervals. 22.Nm Update 23uses the 24.Xr sync 2 25function call to do the task. 26.Pp 27.Nm Update 28is commonly invoked at startup time by 29.Xr rc 8 30when the system goes multi-user. 31.Sh SEE ALSO 32.Xr sync 2 , 33.Xr fsck 8 , 34.Xr init 8 , 35.Xr rc 8 , 36.Xr sync 8 37.Sh BUGS 38It is possible on some systems, that a 39.Nm sync 40occuring simultaneously with a crash may cause 41file system damage. See 42.Xr fsck 8 . 43.Sh HISTORY 44An 45.Nm 46command appeared in Version 6 AT&T UNIX. 47