Unisys MCP & MS-DOS. Two Operating systems. MCP on Unisys mainframes was the most reliable Operating System I ever used. MS-DOS started the world domination o

Unisys MCP & MS-DOS. Two Operating systems. MCP on Unisys mainframes was the most reliable Operating System I ever used. MS-DOS started the world domination of Personal Computers, after a few false / failed starts by other desktop Operating Systems.