>From: Gordon Zaft <zaft@azstarnet.com>

>         Dumb question -- what difference (if any!) is there between a 
>"PDP-10" and a "DECsystem-10"?  I used the latter in the late 70s at U of 
>Ariz.  Is it the same processor but different peripherals?

The PDP-10 is the processor itself.  A DECsystem-10 is a PDP-10, balled up
into the rest of a system, painted blue, and presumably running TOPS-10.
A DECSYSTEM-20 is (or can be) the same thing, painted china red (i.e. orange)
and running TOPS-20.  There's no such thing as a PDP-20 but people like
saying so sometimes, they just mean the PDP-10 inside a DEC-20.

John Wilson
D Bit