B5000
The B5000 was a mainframe computer , to the Burroughs Corporation in 1961 developed. Burroughs merged with Sperry in 1986 to form Unisys .
The B5000 had a modular design and was built with one or two processors and different memory and peripherals. The processors worked as stack machines . The B5000 had a word length of 49 bits with one parity bit . Each magnetic core memory module contained 4096 words (corresponds to 24 KiB), up to eight modules could be connected. There were also up to two drum memories with 32768 words (192 KiB) each.
The operating system - called MCP (Master Control Program) - was, like many user programs, written in ALGOL . There were compilers for an extended ALGOL 60 called Elliot ALGOL and for COBOL , but no assembler .
The term Master Control Program was later used in the film Tron .