[Info-vax] pdp11

[Glenn Everhart]

Yes, I remember running DOS on pdp11; first did that with DOS V4, which became known as DOS/BATCH in V8
and later.

Anyone still interested in running it, I have some old DECtapes (for TU56 drives, yes) that still
have copies of DECUS 11-195 on them. That is a sub-monitor that can either greatly extend (and
somewhat speed up) DOS-11 or also allow it to service 2 users at a time.

(Seeing that you have at most 28K words of memory, it's tough to get more than two sets of
CUSPs in memory at once. However I successfully used it with a 16K word machine with two
users running....one driven by command files. There was also a print spooler that could run
as a kinda/sorta third user in the mix.)

If anyone can still read TU56 I would be glad to let them have the tapes in exchange
for their letting me have a copy of the contents. The DECUS library used to have them but
I don't know that they are still extant anywhere.

DOS-11 would sort of run on DECtape, but there was a limit on its DECtape handling on the
number of files that could be open on one DECtape at a time, which made it not very useful.
Also what with all the swapping from disk that DOS did when PCP11/MFT11 (the DECUS 11-195 thing)
was not loaded, watching it run was an exercise for the VERY patient...a bit like running
VMS on a remote virtual disk over a 9600 baud link. Interesting that it can be done at all,
but not something you do unless desperate for some reason.

Glenn Everhart