From mboxrd@z Thu Jan  1 00:00:00 1970
From: mah@mhorton.net (Mary Ann Horton)
Date: Wed, 1 Feb 2017 08:21:46 -0800
Subject: [TUHS] shared memory on Unix
In-Reply-To: <E198DD1D-4C01-4EF1-AAF4-F3230C28979F@planet.nl>
References: <E198DD1D-4C01-4EF1-AAF4-F3230C28979F@planet.nl>
Message-ID: <1b4095d8-047e-fa23-fc34-b1f8eb5c9d02@mhorton.net>

I*'m not sure what you mean by CB3, but these features (shared memory, 
semaphores, IPC) were added to CB-UNIX (Bell Labs, Columbus) precisely 
because they were needed in real time telco systems and not preset in 
the versions from New Jersey.  This would have been in the early 1980s.  
When I got there in 1981 I think CB-UNIX was already well established 
and had these features.  (These would show up, ironically, in /usr/ucb, 
which did not stand for Berkeley.)

     Mary Ann


On 02/01/2017 06:18 AM, Paul Ruizendaal wrote:
> The presence of some sort of shared memory facility in the
> BBN V6 Unix kernel got me thinking about the origins of
> shared memory on Unix.
>
> I had a vague recollection that primordial versions were present
> in either PWB or CB3, but a quick glance at the source indicates
> that this is not correct.
>
> What are the origins of shared memory on Unix, i.e. what came
> before mmap() and SysV IPC? Was the BBN kernel the first to
> implement such a facility on Unix?
>
> Paul
>