History of IBM Mainframe Operating Systems - System/370 and Virtual Memory Operating Systems

System/370 and Virtual Memory Operating Systems

When System/370 was announced in 1970 it offered essentially the same facilities as System/360 but with about 4 times the processor speeds of similarly-priced System/360 CPUs. Then in 1972 IBM announced "System/370 Advanced Functions", of which the main item was that future sales of System/370 would include virtual memory capability and this could also be retro-fitted to existing System/370 CPUs. Hence IBM also committed to delivering enhanced operating systems which could support the use of virtual memory.

Most of the new operating systems were distinguished from their predecessors by the presence of "/VS" in their names. "VS" stands for "Virtual Storage" - IBM avoided the term "memory", allegedly because it might be interpreted to imply that their computers could forget things.

All of today's IBM mainframe operating systems except z/TPF are descendants of those included in the "System/370 Advanced Functions" announcement - z/TPF is a descendant of ACP, the system which IBM initially developed to support high-volume airline reservations applications.

Read more about this topic:  History Of IBM Mainframe Operating Systems

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