update(8) [osx man page]

UPDATE(8)						    BSD System Manager's Manual 						 UPDATE(8)

NAME

     update -- flush internal filesystem caches to disk frequently

SYNOPSIS

     update

DESCRIPTION

     The update utility has been incorporated into launchd(8).	It historically helped protect the integrity of disk volumes by flushing volatile
     cached filesystem data to disk at thirty second intervals using the sync(2) function call.

SEE ALSO

     sync(2), fsck(8), launchd(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 utility appeared in Version 6 AT&T UNIX.

BSD
								  August 18, 2008							       BSD

sync(2) 							   System Calls 							   sync(2)

NAME

       sync - update super block

SYNOPSIS

       #include <unistd.h>

       void sync(void);

DESCRIPTION

       The  sync() function writes all information in memory that should be on disk, including modified super blocks, modified inodes, and delayed
       block I/O.

       Unlike fsync(3C), which completes the writing before it returns, sync() schedules but does not  necessarily  complete  the  writing  before
       returning.

USAGE

       The  sync()  function  should  be  used	by  applications that examine a file system, such as fsck(1M), and df(1M), and is mandatory before
       rebooting.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       df(1M), fsck(1M), fsync(3C), attributes(5), standards(5)

SunOS 5.11							    5 Jul 1990								   sync(2)