X-Nico

2 unusual facts about Virtual memory


AutoSketch

One limitation of the first DOS release was that it needed to store all of a drawing in RAM, while editing and could not use any sort of swapping.

Memory mapping

Virtual memory, technique which gives an application program the impression that it has contiguous working memory, while in fact it is physically fragmented and may even overflow on to disk storage


Page fault

Contrary to what the name 'page fault' might suggest, page faults are not always errors and are common and necessary to increase the amount of memory available to programs in any operating system that utilizes virtual memory, including Microsoft Windows, Unix-like systems (including Mac OS X, Linux, *BSD, Solaris, AIX, and HP-UX), and z/OS.

University of Michigan Executive System

UMES was in use at the University of Michigan until 1967, when MTS was phased in to take advantage of the newer virtual memory time-sharing technology that became available on the IBM System/360 Model 67.

Virtual storage

virtual memory; IBM uses "virtual storage" rather than "virtual memory"


see also

IBM System/370

In June 1971, on the S/370-145 (one of which had to be 'smuggled' into Cambridge Scientific Center to prevent anybody noticing the arrival of an S/370 at that hotbed of virtual memory development – since this would have signaled that the S/370 was about to receive address relocation technology).

Memory management unit

In the mapping of virtual memory addresses, instead of needing an MMU, the MCP systems are descriptor-based.