UNIX Futures

Doug Gwyn gwyn at brl-smoke.ARPA
Sat Mar 15 10:40:31 AEST 1986


In article <865 at inset.UUCP> boyd at inset.UUCP (Boyd Roberts) writes:
>
>The SysV shl is a much better implementation, because it's a "bolt-on".
>Not, a huge kernel/user level kludge/rewrite (4.N approach).

This isn't quite right.  "shl" depends on the addition of an "sxt"
pseudo-device driver to the UNIX System V kernel, since otherwise
UNIX System V has no multiplexing or pseudoterminals.  It also
requires the addition of another special "switch" control character.
It is true that the changes necessary to add shl/sxt are less
extensive and less intrusive than those needed for 4BSD job control.

>The way to go is to buy a jerq (5620) and somehow run the V8 mux/jim etc.
>The stuff that comes with SysV is truly revolting, and almost unusable.
>Invest some time into fixing the SysVile layers mess.

The Blit/Jerq/DMD is indeed a nice alternative to job control,
but of course it is not quite the same thing.  I have both here
and have found job control to still be of some (minimal) utility.
I would much prefer full 8th Edition UNIX process control, though.
Does anybody know for sure whether SVR3 includes this?

Software for the Teletype 5620 (DMD) is available from AT&T.  They
provide it for VAX or various 3B machines, UNIX System V only; there
is also a 4.2BSD port distributed by Teletype.  At BRL we run the
DMD software on a 4.3BSD kernel; it was built under our UNIX System
V emulation, essentially unmodified except for layers, which was
totally replaced by "mpx" (originally obtained from Teletype, then
heavily modified at CWI in the Netherlands).  The only thing missing
is the hostagent feature, which can't be made to work reasonably
with the Berkeley implementation of pseudo-terminals.  I have also
ported the DMD software to the Gould PowerNode (60x0/90x0) family.
This software is available to sites that are properly licensed for
it, as an added part of the BRL UNIX System V emulation for 4.2BSD.



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