:this article is about the mit computation center operating system. ctss may also stand for the cray time sharing system, a separate system developed for cray supercomputers.  the compatible time-sharing system (ctss), was one of the first time-sharing operating systems; it was developed at mit's computation center. ctss was first demonstrated in 1961, and was operated at mit until 1973. during part of this time, mit's project mac had a second copy of ctss, but the system did not spread beyond two sites (though this applies to many early computer systems). 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.  ==overview== the "compatible" in the name refers to backwards compatibility with the standard batch processing os for the ibm 7094, the fortran monitor system (fms). ctss ran an unaltered copy of fms, processing a standard batch stream, in a pseudo-virtual 7094 provided by its background facility. (the hardware was partly but not fully virtualized; see history of cp/cms for further details.) background fms jobs could access tapes normally, but could not interfere with foreground time-sharing processes or the resources used to support them. ctss was very influential. it showed that time-sharing was viable; it fostered important new applications for computers; it had a significant influence on the next generation of time-sharing systems (notably cp/cms); and its direct successor, multics, pioneered many core concepts of current operating systems. ==characteristics== * ctss had one of the first computerized text formatting utilities, called runoff. * ctss had one of the first inter-user messaging implementations, possibly inventing email.tom van vleck's memoir of the history of electronic mail * mit computation center staff member louis pouzin created for ctss a command called runcom, which executed a list of commands contained in a file. (he later created a design for the multics shell, which in turn inspired unix shell scripts.) runcom also allowed param
1960s_software Discontinued_operating_systems Massachusetts_Institute_of_Technology Time-sharing_operating_systems