Compatible Time-Sharing System

The Compatible Time - Sharing System ( CTSS ) was one of the first multi-user systems. It was developed in the early 60s at MIT and used until 1973.

CTSS was developed and operated 7094 mainframe on a modified IBM.

The "Compatible " in the name referred to run in the background on the possibility of an unmodified copy of the Fortran Monitor System ( FMS). This made it possible to continue using the developed under this batch processing operating system programs.

At the beginning of the use, there was a problem, and indeed it was found that larger programs ever ran and never came to a conclusion. This occurred due to an error in the code, wherein the users only one priority is assigned to that determined the assigned amount of hardware resources. So visitors with more and more users new one to run a small program that was the big, lengthy programs taken more and more power available, so this could not be executed completely. This error has been detected after some time and Tom Hastings, a co-developer of the system, add a Subpriorität solved by.

CTSS is considered the precursor of Multics, which in turn is the precursor of Unix.