From mboxrd@z Thu Jan 1 00:00:00 1970 From: drsalists@gmail.com (Dan Stromberg) Date: Wed, 16 Jul 2014 19:09:11 -0700 Subject: [TUHS] shutdown for pre-v7 unix In-Reply-To: References: Message-ID: On Wed, Jul 16, 2014 at 2:12 PM, Dave Horsfall wrote: > On Wed, 16 Jul 2014, Mark Longridge wrote: > >> I've been typing sync;sync at the shell prompt then hitting ctrl-e to >> get out of simh to shutdown v5 and v6 unix. > > The "correct" way used to be: > > sync > sync > sync 3 sync's was net.wisdom for a long time, but some discussions in the Linux mailing lists suggested that 2 was enough all along. The first schedules all dirty buffers to be flushed to disk. The second does the same, but to provide an ordering guarantee, doesn't return until the dirty buffers from the first are finished. Hence the 2. But I'm a relative newcomer to *ix - I didn't get involved until SunOS 4.