sync - update disk
sync() causes all information in memory that should be on disk to be
written out. This includes modified file system meta-data and delayed
It should be used by commands and programs that examine a file system,
such as fsck, df, etc. It is mandatory before a shutdown.
The writing, although scheduled, is not necessarily complete upon
return from sync.
In some HP-UX systems, sync() may be reduced to a no-op. This is
permissible on a system which does not cache buffers, or in a system
that in some way ensures that the disks are always in a consistent
sync() was developed by HP and AT&T Bell Laboratories.
sync(1M), fdatasync(2), fsync(2).
sync(): SVID2, SVID3, XPG2
Hewlett-Packard Company - 1 - HP-UX Release 11i: November 2000