[TUHS] shutdown for pre-v7 unix

[Norman Wilson]

After a day and an evening of fighting with modern hardware,
the modern tangle that passes for UNIX nowadays, and modern
e-merchandising, I am too lazy to go look up the details.

But as I remember it, two syncs was indeed probably enough.
I believe that when sync(2) returned, all unflushed I/O had
been queued to the device driver, but not necessarily finished,
so the second sync was just a time-filling no-op.  If all the
disks were in view, it probably sufficed just to watch them
until all the lights (little incandescent bulbs in those days,
not LEDs) had stopped blinking.

I usually typed sync three or four times myself.  It gave me
a comfortable feeling (the opposite of a syncing feeling, I
suppose).  I still occasionally type `sync' to the shell as
a sort of comfort word while thinking about what I'm going
to do next.  Old habits die hard.

(sync; sync; sync)

Norman Wilson
Toronto ON