MVT
MVT is an acronym for Multiprogramming with a Variable number of Tasks. It was intended as the operating system for the larger machines in the System/360 family, introduced in 1964, but MVT did not become available until 1967. Early versions had many problems and the simpler MFT continued in use for many years. It is a very old forerunner of IBM's MVS and z/OS.
Long since dead and buried, it is of historical interest as the most advanced of the early OS/360 operating systems and the one most influential in later developments.
In particular, the I/O queueing of all the OS/360 family left a lot to be desired. This was addressed by a 3rd party package, HASP, the Houston Automated Spooling Package. In MVS, HASP became JES, the Job Entry Subsystem (either JES2 or JES3), and it was many years before the HASP labels were removed from the JES source.
See Also: OS/360
