> 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
