Gary Sielaff wrote:
>
> Was VM Virtual Memory or Virtual Machine?
> Just Curious in Moses Lake

Virtual Machine.  Current incarnation is VM/ESA (Virtual Machine,
Extended System Architecture).  ESA allowed full 32-bit addressing.
While IBM has always had a 32-bit "word", addressing was done with
the low-order 24 bits (high-order bits somewhat platform dependent,
but generally storage protection key).  ESA provided a full 32 bits.

Abbreviated OS acronym history:

DOS - Disk Operating System (and they had it long before Gates)
DOS/VS - DOS/Virtual Storage
OS - Operating System (OS360 and later OS370)
OS/MFT - OS, Multitasking with a Fixed number of Tasks (fixed partition)
OS/MVT - OS, Multitasking with Variable number of Tasks
OS/VS - OS, Virtual Storage
OS/MVS - OS, Multiple Virtual Storage (each task has its own space)

Jeff Kell <[log in to unmask]>