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Compatible Time-Sharing System
The Compatible Time-Sharing System (CTSS) was the first general purpose time-sharing operating system. Compatible Time Sharing is time sharing which is compatible with batch processing, in that they operate concurrently.
CTSS was developed at the MIT Computation Center ("Comp Center"). CTSS was first demonstrated on MIT's modified IBM 709 in November 1961. The hardware was replaced with a modified IBM 7090 in 1962 and later a modified IBM 7094 called the "blue machine" to distinguish it from the Project MAC CTSS IBM 7094. Routine service to MIT Comp Center users began in the summer of 1963 and was operated there until 1968.
A second deployment of CTSS on a separate IBM 7094 that was received in October 1963 (the "red machine") was used early on in Project MAC until 1969 when the red machine was moved to the Information Processing Center and operated until July 20, 1973. CTSS ran on only those two machines; however, there were remote CTSS users outside of MIT including ones in California, South America, the University of Edinburgh and the University of Oxford.
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". 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".
In June 1959, Christopher Strachey published a paper "Time Sharing in Large Fast Computers" at the UNESCO Information Processing Conference in Paris, where he envisaged a programmer debugging a program at a console (like a teletype) connected to the computer, while another program was running in the computer at the same time. 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.
John McCarthy wrote a memo about that[clarification needed] at MIT, after which a preliminary study committee and then a working committee were established at MIT, to develop time sharing. The committees envisaged many users using the computer at the same time, decided the details of implementing such system at MIT, and started the development of the system.
By July 1961 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. On May 3, 1962, F. J. Corbató, M. M. Daggett and R. C. Daley published a paper about that system at the Spring Joint Computer Conference. "[M]ajor portions of [the CTSS system were largely prepared by]: Mrs. Marjorie M. Daggett, Mr. Robert Daley, Mr. Robert Creasy, Mrs. Jessica Hellwig, Mr. Richard Orenstein, and Professor F. J. Corbató".
The system used an IBM 7090, modified by Herbert M. Teager, with added 3 Flexowriters for user consoles, and maybe a timer. Each of the 3 users had two tape units, one for the user's file directory, and one for dumping the core (program in memory). There was also one tape unit for the system commands, there were no disk drives. The memory was 27 k words (36-bit words) for users, and 5 k words for the supervisor (operating system).
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Compatible Time-Sharing System AI simulator
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Compatible Time-Sharing System
The Compatible Time-Sharing System (CTSS) was the first general purpose time-sharing operating system. Compatible Time Sharing is time sharing which is compatible with batch processing, in that they operate concurrently.
CTSS was developed at the MIT Computation Center ("Comp Center"). CTSS was first demonstrated on MIT's modified IBM 709 in November 1961. The hardware was replaced with a modified IBM 7090 in 1962 and later a modified IBM 7094 called the "blue machine" to distinguish it from the Project MAC CTSS IBM 7094. Routine service to MIT Comp Center users began in the summer of 1963 and was operated there until 1968.
A second deployment of CTSS on a separate IBM 7094 that was received in October 1963 (the "red machine") was used early on in Project MAC until 1969 when the red machine was moved to the Information Processing Center and operated until July 20, 1973. CTSS ran on only those two machines; however, there were remote CTSS users outside of MIT including ones in California, South America, the University of Edinburgh and the University of Oxford.
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". 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".
In June 1959, Christopher Strachey published a paper "Time Sharing in Large Fast Computers" at the UNESCO Information Processing Conference in Paris, where he envisaged a programmer debugging a program at a console (like a teletype) connected to the computer, while another program was running in the computer at the same time. 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.
John McCarthy wrote a memo about that[clarification needed] at MIT, after which a preliminary study committee and then a working committee were established at MIT, to develop time sharing. The committees envisaged many users using the computer at the same time, decided the details of implementing such system at MIT, and started the development of the system.
By July 1961 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. On May 3, 1962, F. J. Corbató, M. M. Daggett and R. C. Daley published a paper about that system at the Spring Joint Computer Conference. "[M]ajor portions of [the CTSS system were largely prepared by]: Mrs. Marjorie M. Daggett, Mr. Robert Daley, Mr. Robert Creasy, Mrs. Jessica Hellwig, Mr. Richard Orenstein, and Professor F. J. Corbató".
The system used an IBM 7090, modified by Herbert M. Teager, with added 3 Flexowriters for user consoles, and maybe a timer. Each of the 3 users had two tape units, one for the user's file directory, and one for dumping the core (program in memory). There was also one tape unit for the system commands, there were no disk drives. The memory was 27 k words (36-bit words) for users, and 5 k words for the supervisor (operating system).