X-Nico

4 unusual facts about Plessey System 250


CAP computer

Instead of the programmer-visible registers used in Chicago and Plessey System 250 designs, the CAP would load internal registers silently when a program defined a capability.

IBM System/38

(The earlier Plessey 250 was one of the few other computers with capability architecture ever sold commercially).

Plessey

Plessey was also the lead contractor for the Ptarmigan communications system supplied to the British Army that adopted the Plessey System 250 architecture.

By 1972 Plessey designed the first industrial Capability-based security computer, a fault-tolerant multiprocessor system called Plessey System 250.



see also