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From: minow@mountn.dec.com (Martin Minow)
Newsgroups: comp.sys.dec
Subject: Re: Unix for PDP-11/23s
Message-ID: <1860@mountn.dec.com>
Date: 20 Aug 90 13:33:07 GMT
References: <14695@shlump.nac.dec.com>
Reply-To: minow@bolt.enet.dec.com (Martin Minow)
Distribution: usa
Organization: Digital Equipment Corporation
Lines: 33

In article <1990Aug19.034635.26429@virtech.uucp>, rickr@virtech.uucp (Rick
Rodman) writes...

>1. Of the four operating systems once offered for the PDP-11, RSX, RT-11,
>RSTS, and Ultrix, Digital has discontinued only one: Ultrix (Unix).
>So much for Digital's commitment to Unix.

Digital has also "discontinued" several other operating systems for
the PDP-11:

-- Dos-11 and Dos-Batch.  (replaced by RT11).
-- IOX (paper-tape operating system).
-- Caps-11 (IOX for casette tapes).
-- RSTS-11 (RSTS/E running on an 11/20; replaced by RSTS/E).
-- RSX-11D (replaced by RSX-11M and IAS).
-- RSX-11B and -C (replaced by RSX-11S (?) and RSX-11M).  Hmm, maybe
   RSX-11S is also obsolete.
-- RSX-11A (replaced by other RSX variants).
-- Multi-user Basic (4 Basic-users on an unmapped PDP-11).
-- Focal (stand-alone).
-- Mumps-11 (replaced by Digital Standard Mumps).
-- Trax-11.

Most of these appeared and disappeared in the early to mid 1970's.
All of them were "operating systems" in the sense that they had a
command-line interface and a centralized mechanism for device-independent
I/O.  Some of them, such as RSTS-11, had "systems programs" written in a high-
level language.  (RSX-11A, -B, -C, and -S were intended for embedded systems
rather than programming and often did not have either command-line,
programming, or file systems).

Martin Minow.
minow@bolt.enet.dec.com