Unix on top of/in parallel with other operating systems

[meissner at dg_rtp.UUCP]

Disclaimer -- I work for Data General (C compiler), but will try to keep hype
out of this discussion.

At Data General, we have two versions of UNIX, one that runs in conjuction with
our properitary OS's (MV/UX), and one that runs native (DG/UX).  The fortran
(and C and Pascal) compilers are the same under both systems.  I don't have
performance figures, but our fortran is competive with VMS fortran.

The DG gear runs on a propritary architecture with machines from .5MIPS to
5MIPS for uniprocessors, and a 10MIP dual processor (DG/UX, the native UNIX,
currently does not support the dual processor, but is working on it).

MV/UX runs under either AOS/VS or AOS/DVS.  MV/UX users can transparently
access AOS/VS files, processes, etc.  Similarly, you can invoke MV/UX processes
from the AOS/VS (AOS/DVS) command line interpreter.  Since MV/UX is based
on a library that translates UNIX system calls into AOS/VS (AOS/DVS) system
calls, there are some features of UNIX that can't eaisly be translated.  The
underlying AOS/VS operating system has been out in the field for 5+ years,
and there are various tools to tune systems to increase performance.  MV/UX
is currently based on system V UNIX (the next rev will be system V.2) with
some berkley features (csh, vi).  There is limited TCP/IP (ie, you can't write
sockets in user programs yet) ethernet support, as well as X.25 ethernet/sync
support.  AOS/DVS is a superset of AOS/VS for a distributed environment that
was announced last november.

DG/UX runs native on the hardware, and supports full system V.2, as well as
most of berkley 4.2.  It has only been out for 1 1/2 - 2 years, and so is
still maturing.

In terms of performance, DG/UX seems faster for normal job mixes, though I
suspect that AOS/VS wins in cases like large fortranish finite element
cases, because you have more tuning capability.

	Michael Meissner
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