I was dismissive of the DTSS when I first saw the interface. When I learned how it was implemented and the hardware required I became very impressed. It was a classic case of genius removing complexity. It was basically a batch system modified to yield the main benefits of time sharing while avoiding a great deal of the complexity of later full fledged systems. One very small computer would interact by keystrokes with several teletypes in support of a users editing an input file, usually a program, and examining output of a previous run. The second computer, a bit larger, ran a conventional batch system, providing short runs, getting its inputs from a disk shared between the two computers.

Comparing CTSS with DTSS yields the following points: CTSS could run arbitrary machine language programs while maintaining control of the entire system; DTSS could only run arbitrary Basic programs. The CTSS editor and compiler were replaceable by user; the DTSS editor and compiler were built in.

The lines of the program were numbered; the DTSS system would collect concurrent character streams from many terminals to be interpreted as program updates. When updates were ready the updates would be applied to the previous program version and compiled and executed. The language was Basic and the interpreter limited the run time of the program.

Several complex components of a multi programmed kernel were thus avoided while still providing very quick turn-arround, especially compared with programs submitted to batch systems on cards.

This is the most complete description of DTSS that I have found.