Operating System (OS)
Memory management is :

not used on multiprogramming systems
not used in modern operating system
critical for even the simplest operating systems
None of these
replaced with virtual memory on current systems

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Operating System (OS)
Most of the microcomputer's operating systems like Apple DOS, MS DOS and PC DOS etc. are called disk operating systems because

they are partly in primary memory and partly on disk
they are memory resident
they are initially stored on disk
they are available on magnetic tapes
None of these

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