Yeah - they are different, but I'm pretty sure that Dale's work in CB UNIX came first.   I know I saw the CB/UNIX code as hacks to PWB 1.0 I think (maybe 2.0) when I was still at CMU in 1978 (Phil Karn had it IIRC).   I was under the impression that folks at Summit (e.g. UNIX Support Group) had the job of collecting different features that had been done and putting them into the AT&T 'Standard' for the operating companies.  I agree it would be interesting to learn who did the work.  But as I always understood it, Dale's team gave the CB/UNIX stuff to the USG folks who reimplemented it, I thought because USG was redoing the memory code and wanted something that would integrate better.   I suspect it is also possible, Dale and his team redid it in the key of System V at some point and pushed it back. 


On Sat, Jul 24, 2021 at 2:38 PM Paul Ruizendaal via TUHS <> wrote:
Currently reading through IPC in CB Unix 3.0, Vr1-vax and SVr1-pdp11.

The IPC primitives in CB Unix (maus, event and msg) are quite different from those in SVr1 (although maus survives in SVr1-pdp11).

It made me wonder: is it still known who designed the IPC primitives for SysV?