In 1964, Multics was developed initially for the GE-645 mainframe, a 36-bit system; later around 1973, it was supported on the Honeywell 6180 series machines.
In 1985, Multics was issued certification as a B2 level secure operating system using the Trusted Computer System Evaluation Criteria from the National Computer Security Center (NCSC) a division of the NSA, the first operating system evaluated to this level.