GE 645

The GE 645 mainframe computer was a development of the GE 635 for use in the Multics project. This was the first computer that implemented a configurable hardware protected memory system. It was designed to satisfy the requirements of Project MAC to develop a platform that would host their proposed next generation time-sharing operating system (Multics) and to meet the requirements of a theorized computer utility. The system was the first truly symmetric multiprocessing machine to use virtual memory, it was also among the first machines to implement what is now known as a translation lookaside buffer, the foundational patent for which was granted to John Couleur and Edward Glaser.

General Electric initially publicly announced the GE 645 at the Fall Joint Computer Conference in November 1965. At a subsequent press conference in December of that year it was announced that they would be working towards "broad commercial availability" of the system. However they would subsequently withdraw it from active marketing at the end of 1966. In total at least 6 sites ran GE 645 systems in the period from 1967 to 1975.