* Dartmouth Time Sharing System (DTSS) → GE Time-sharing → GEnie* DEC PDP-6 Time-sharing Monitor → TOPS-10 → TSS-8, RSTS-11, RSX-11 → VAX/VMS* HP 2000 Time-Shared BASIC* IBM CALL/360, CALL/OS - using IBM 360/50* IBM CP-40 → CP-67 → CP-370 → CP/CMS → VM/CMS* IBM TSO for OS/MVT → for OS/VS2 → for MVS → for z/OS* IBM TSS/360 → TSS/370* International Timesharing Corporation on dual CDC 3300 systems.
* Dartmouth Time Sharing System (DTSS) → GE Time-sharing → GEnie* DEC PDP-6 Time-sharing Monitor → TOPS-10 → TSS-8, RSTS-11, RSX-11 → VAX/VMS* HP 2000 Time-Shared BASIC* IBM CALL/360, CALL/OS - using IBM 360/50* IBM CP-40 → CP-67 → CP-370 → CP/CMS → VM/CMS* IBM TSO for OS/MVT → for OS/VS2 → for MVS → for z/OS* IBM TSS/360 → TSS/370* International Timesharing Corporation on dual CDC 3300 systems.