From mboxrd@z Thu Jan  1 00:00:00 1970
From: lm@mcvoy.com (Larry McVoy)
Date: Mon, 6 Mar 2017 07:34:53 -0800
Subject: [TUHS] [TUHS} communication files: interprocess IO before pipes
In-Reply-To: <201703060350.v263oM7u024080@coolidge.cs.Dartmouth.EDU>
References: <201703060350.v263oM7u024080@coolidge.cs.Dartmouth.EDU>
Message-ID: <20170306153453.GL16343@mcvoy.com>

On Sun, Mar 05, 2017 at 10:50:22PM -0500, Doug McIlroy wrote:
> It's not really Unix history, but Dartmouth's "communication files"
> have so often been cited as pipes before Unix, that you may like
> to know what this fascinating facility actually was. See
> http://www.cs.dartmouth.edu/~doug/DTSS/commfiles.pdf

If I'm understanding correctly, an I/O on the slave side would cause
an event on the master side.  So the master was almost like a debugger
with break points at open/read/write/lseek/close?

That would explain a lot of the complexity.  And if the slave does a
read(comm, buf, 1<<20) I suspect that the master does multiple writes?
As in is there a PIPEBUF analogy?
-- 
---
Larry McVoy            	     lm at mcvoy.com             http://www.mcvoy.com/lm