RSTS/E has just had its 50th Birthday...

Ethan Dicks ethan.dicks at
Mon Jun 29 12:02:36 CDT 2020

On Sun, Jun 28, 2020 at 2:36 PM Paul Koning via cctalk
<cctalk at> wrote:
> > Err, I expect that that was RSTS-11 in June, 1970, not RSTS-E. Since RSTS-11
> > (which I learned to program on; happy memories :-) was a BASIC-PLUS only
> > system, and ran on a PDP-11/20, I suspect it was a fairly different operating
> > system (although no doubt it's BASIC-PLUS interpreter was ported to RSTS-E).
> >
> > I think RSTS/E needed the -11/45, introduced around June 1972; sources
> > give 1973 for RSTS/E.

I came to RSTS some time later (not counting dialling from a
DECwriter, I first really used RSTS/E in 1984) but with the difference
between RSTS-11 and RSTS/E, I went over David Ahl's "101 BASIC
Computing Games" to figure out from the code, from the run listings,
and from the descriptions, which of the many systems were used.  I
found references identifying about 40% of the games, and relevant to
this thread, ANIMAL and BLKJAC mention RSTS-11, several mention RSTS/E
mentions the EduSystem 70 (HRMABI).  In various places I've found
mention of the EduSystem 60 (single-user on a 4K PDP-11/20), the
EduSystem 70 (up to 8 users on a 16K PDP-11/20), and the EduSystem 80
(up to 16 users on a 24K PDP-11/20 and a specific mention or RSTS-11).
The EduSystem handbook (1973 publication date) only covers up to the
EduSystem 50 so I don't have configuration details of any of the

As I mention from time to time, I have an 11/20 that needs extensive
restoration work (it was rescued from the dumpster at work after my
supervisor stripped out fans and PSUs) and I'd love to find things to
run on it other than paper tape and toggle-in programs.  Finding a
copy of an EduSystem distro would be fantastic for demos.



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