Scientific Data Systems of El Segundo, California, produced a line of 24-bit computers in the early and mid 1960's. The first system, the SDS 900, was succeeded by the SDS 920 and SDS 930. Project Genie at the University of California Berkeley modified the SDS 930 to increase its memory address capability and add support for timesharing. The Project Genie timesharing system provided many of the seminal ideas for Tenex and thus TOPS-20.
The SDS 940 is a commercial version of Project Genie's modified SDS 930. It was succeeded by the SDS 9300, which was not compatible. After the 9300, SDS built 32b systems, the SDS (and then XDS) Sigma series.
| Option | Description | Capacity |
| CPU and memory | SDS 940 | 16KW - 64KW |
| CPU options | Genie mode or SDS 940 mode I/O decoding | |
| Console | integral typewriter | |
| Paper tape | integral tape reader | |
| integral paper tape punch | ||
| Real time clock | integral | |
| Line printer | line printer | |
| Drum | Project Genie drum | 1376KW |
| Fixed head disk | rapid access disk | 2097KW |
| Moving head disk | 9164 moving head disk | 16777KW |
| Magnetic tape | 7-track magnetic tape |
Updated 08-Aug-2020 by Bob Supnik (simh AT groups DOT io - anti-spam encoded)