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Date:      Tue, 25 Jun 1996 16:12:49 -0400 (EDT)
From:      Bill/Carolyn Pechter <pechter@shell.monmouth.com>
To:        terry@lambert.org (Terry Lambert)
Cc:        freebsd-chat@freefall.FreeBSD.org
Subject:   Re: int link(const int inode, const char *name2)
Message-ID:  <199606252012.QAA13809@shell.monmouth.com>
In-Reply-To: <199606251838.LAA00282@phaeton.artisoft.com> from "Terry Lambert" at Jun 25, 96 11:38:42 am

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> 
> > > sync;sync;sync
> > 
> > That bit of ancient history is purely psychological. Since sync
> > isn't synchronous, after the command returns, your buffers aren't
> > all written. However, after you've typed the command twice again,
> > odds are they are. :-)
> 
> Actually, 3 sync's is superstition.
> 

Not really, they were a time delay -- the old 11/70's would take a 
while to sync to the RP04/5/6 or even RK disk drives.

Typing sync<cr>
sync<cr>
sync<cr>

with a 300 baud DECwriter gave a significant time delay before hitting
the halt switch.

The story is sync;sync;sync  wasn't good enough -- if the halt switch 
on the 11/70 was in reach easily...


> Two syncs was a trigger for a cache flush on a number of older UNIX
> and UNIX-like systems.  The second sync would wait, since the kernel
> knew that there was a sync pending.
> 

OK, I'll buy this.

> One could argue on an old (but active) system, you'd type sync until
> it hung for a bit.  Maybe the first one was preterbed by loading the
> sync code itself?
> 
> 
> 					Terry Lambert
> 					terry@lambert.org

I still think the third sync was "operator carriage return fill characters."
Keep them from hitting the big red switch (or magenta) too soon.

Bill
ex-11/70 RP04 Board swapper
-------------------------------------------------------------------------------
 Bill Pechter/Carolyn Pechter  | 17 Meredith Drive, Tinton Falls, NJ 07724, 
 908-389-3592                  | pechter@shell.monmouth.com                
 I'll run Win95 on my box when you pry the keyboard from my cold, dead
 hands.  FreeBSD, OS/2, CP/M, RT11, spoken here.



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