Multiprocessor Qbus PDP-11

Paul Koning paulkoning at
Fri Aug 20 15:14:49 CDT 2021

> On Aug 20, 2021, at 4:07 PM, Guy Sotomayor via cctalk <cctalk at> wrote:
> There were a couple of other PDP-11 multiprocessors that I know of (and used):
> * C.MMP (eventually 16 PDP-11/40e's in an SMP configuration with a
>   crosspoint switch accessing a large memory).  It ran a capability
>   based OS called Hydra.
> * CM*  this was a cluster of LSI-11s (as I recall) that were
>   hierachially interconnected to allow for distributed operation (I
>   think it was potentially capable of running with 255 nodes). I don't
>   recall what OS CM* used.
> Of course both of the above did not use off the shelf OS's or software.
> TTFN - Guy

Did you ever run across an ALGOL-68 compiler for either of these?  At one time (while at the U of Illinois I think, late 1970s, or perhaps a few years later at DEC) I had a set of DECtapes that contained the run time libraries for that compiler.  I think they were in Bliss, and PDP-10 format DECtapes.  I lost them at some point, unfortunately, and I never had the compiler itself.

Some vague memory says it was an ALGOL-68 subset; most compilers were, ALGOL-68 is a rather difficult language to compile if you want to support the whole thing.


More information about the cctalk mailing list