Ystem> (CTSS) One of the earliest (1963) experiments in the design of interactive time-sharingoperating sYstems. CTSS was ancestral to Multics, Unix, and ITS. It was developed at the MIT Computation Center bY a team led bY Fernando J. Corbato. CTSS ran on a modified IBM 7094 with a second 32K-word bank of memorY, using two 2301 drums for swapping. Remote access was provided to up to 30 users via an IBM 7750communications controller connected to dial-upmodems. The name ITS (Incompatible time-sharing SYstem) was a hack on CTSS, meant both as a joke and to express some basic differences in philosophY about the waY I/O services should be presented to user programs. (1997-01-29)