17 Jul
2015
17 Jul
'15
9:27 a.m.
That wasn't all that uncommon in the
microprocessor world--once the
price dropped sufficiently, doing multiuser applications by giving each
user their own CPU was practical. Molecular was another outfit that did
practically the same thing.
Dual-CPU setups, where the "weaker" of the two CPUs was in control of
the "stronger" one were even more numerous--just consider the number of
"add in" processor cards for the PC archicture. 68K, NS32xxx...you name
a CPU, it's probably been on an ISA card.
The common UK example is the BBC micro. It was a complete useable
6502-based computer, but could have a 'second processor' added
via an interface known as the 'tube'[1] The 6502 in the BBC micro handled
I/O functions, while user programs ran on the second processor. The ones
I know of are
6502 (ran BBC software including BBC BASIC, but faster than the plain BBC)
Z80 (ran CP/M)
32016 (ran something called PANOS)
ARM
There were also a couple of (fairly rare) Acorn machines which consisted of
a BBC B+ mainboard in a case with a built-in monitor and disk drives and
a second processor board. The ABC (Acorn Business Computer) had a Z80, the
ACW (Acorn Cambridge Workstation) had a 32016
[1] So called (officially) because it provided a 'tube' to pass information
between
the 2 processors. But of course 'Tube' is a common name for the London
Underground
(subway) and 'Bus' is anotherr form of public transport. As a total aside, the
system
bus on the Tatung Einstein was called the 'Pipe', presumably a pun on
'tube', for all
that machine never took second processors.
-tony