Burroughs MCP

The MCP (Master Control Program) is the proprietary operating system of the Burroughs large systems including the Unisys Clearpath/MCP systems. Originally written in 1961 in ESPOL (Executive Systems Programming Language), which itself was an extension of Burroughs Extended ALGOL, in the 1970s it was converted to NEWP, a better structured, more robust, and more secure form of ESPOL. The MCP was a leader in many areas, including: the first operating system to manage multiple processors, the first commercial implementation of virtual memory, and the first OS written exclusively in a high-level language.