Burroughs B5000

The B5000 was a mainframe computer introduced by the Burroughs Corporation in 1961. It was notable for being:

• an early dual-processor system with segmented memory hardware
• implemented as a stack machine
• programmable in a Burroughs-specific ALGOL 60 extension known as Elliot ALGOL (implemented by C.A.R. Hoare)

Besides the end-user applications, the operating system itself (called MCP, short for Master Control Program), was programmed in Elliot ALGOL—almost a decade before the creation of Unix.

Furthermore, the command interface (à la job control language) was eventually developed into a compiled, structured, procedural programming language called WFL (short for Work Flow Language).