[TUHS] [TUHS} communication files: interprocess IO before pipes

Larry McVoy lm at mcvoy.com
Tue Mar 7 01:34:53 AEST 2017

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 

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