[Info-vax] OT: obscure PDP11 OSes (even more dinosaury)

[Lederman]

Someone mentioned the PDP-11/74

I was active in RSX-11M and M+ using mostly 11/70s at that time,
and like many others, thought having an 11/74 would be a good
thing.

Some years later I saw a presentation at a DECUS symposium
by one of the chief RSX people (don't remember who, but
I don't think it was Brian McCarthy) who showed photos
and diagrams of the 11/74.  Interconnecting the memory
systems of the four machines used 100 cables, and therefore,
200 memory cable connections. And though the sockets had
keyways, the cables did not have keys, so it was possible to
plug them in the wrong way.

If, like me, you ever had to connect memory on even a single
PDP-11/70, you would never, ever want to run an 11/74.

As for which was faster, it all depended on what you did
and which systems were involved. The company I worked
for was going to get an 11/44 for a project, but DEC cut
a deal to get us a VAX-11/730 for the same price. It was
an o.k. machine, and we got VMS experience, but there
was no way it was going to run our application as fast
as an 11/44 would have.  Fortunately, or plans for the
system (and some corporate raider's plans for our
division) meant that the system never had to run fast
enough.

Bart.


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