[1][5] John Backus said in the 1954 summer session at MIT that "By time sharing, a big computer could be used as several small ones; there would need to be a reading station for each user".

[6] Computers at that time, like IBM 704, were not powerful enough to implement such system, but at the end of 1958, MIT's Computation Center nevertheless added a typewriter input to its 704 with the intent that a programmer or operator could "obtain additional answers from the machine on a time-sharing basis with other programs using the machine simultaneously".

[8][9] Debugging programs was an important problem at that time, because with batch processing, it then often took a day from submitting a changed code, to getting the results.

By July, 1961[10] a few time sharing commands had become operational on the Computation Center's IBM 709, and in November 1961, Fernando J. Corbató demonstrated at MIT what was called the Experimental Time-Sharing System.

The console commands implemented at the time were login, logout, input, edit, fap, mad, madtrn, load, use, start, skippm, listf, printf, xdump and xundump.

[13][14] DOTSYS on CTSS was first demonstrated on August 18, 1966, as part of a feasibility study where teletypesetter tape, in the form of news, was converted to Grade 2 Braille.

The following month the feasibility of converting textbook information on teletypesetter tape to error-free Grade 2 Braille was successfully demonstrated.

[15] As MIT CTSS was an academic system, a research vehicle and not a system for commercial computing, two years later a version of DOTSYS stripped of CTSS dependencies for software portability was used on an IBM 709 at the American Printing House for the Blind to print the first braille edition of a book produced from teletypesetter input, only a few weeks after the ink-print version.

Intrex was an experimental, pilot-model machine-oriented bibliographic storage and retrieval system with a database that stored a catalog of roughly 15,000 journal articles.

[18][19][20] A deployment of three BRISC CRT consoles for testing at the MIT Engineering Library showed that it was preferred over two other systems, ARDS and DATEL.

CTSS had a protected-mode kernel; the supervisor's functions in the A-core (memory bank A) could be called only by software interrupts, as in modern operating systems.

[8] Processor allocation scheduling with a quantum time unit 200 ms, was controlled by a multilevel feedback queue.

These included six data channels connecting to: CTSS was described in a paper presented at the 1962 Spring Joint Computer Conference, and greatly influenced the design of other early time-sharing systems.