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From: wkt@tuhs.org (Warren Toomey)
Subject: [TUHS] Pipes in the Third Edition Unix
Date: Wed, 4 Jan 2017 07:53:10 +1000	[thread overview]
Message-ID: <20170103215310.GA26242@minnie.tuhs.org> (raw)
In-Reply-To: <d9dd5f1e-f686-c642-5f55-3904946c9489@aueb.gr>

On Tue, Jan 03, 2017 at 10:54:57PM +0200, Diomidis Spinellis wrote:
> Peter Salus writes "The other innovation present in the Third Edition was
> the pipe" ("A Quarter Century of Unix", p. 50).  Yet, in the corresponding
> sys/ken/sysent.c, the pipe system call seems to be a stump.

The Third edition was still written in assembly code. The Fourth edition
was the first to be rewritten in C. So there was a time when both
existed in parallel.
 
>         1, &fpe,                        /* 40 = fpe */
>         0, &dup,                        /* 41 = dup */
>         0, &nosys,                      /* 42 = pipe */
>         1, &times,                      /* 43 = times */

This code, from the nsys kernel, clearly shows this. The kernel was
being rewritten in C. The C version had not yet caught up with the
functionality in the assembly version of the kernel, which did have pipes.

Cheers, Warren


  parent reply	other threads:[~2017-01-03 21:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-03 20:54 Diomidis Spinellis
2017-01-03 21:50 ` Clem Cole
2017-01-03 21:53 ` Warren Toomey [this message]
2017-01-03 22:04   ` Warren Toomey
2017-01-03 22:20     ` Paul Ruizendaal
2017-01-05  0:51     ` Dave Horsfall
2017-01-03 22:14 Norman Wilson
2017-01-03 23:52 Noel Chiappa

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