DOS Memory Management

In IBM PC compatible computing, DOS memory management refers to software and techniques employed to give applications access to more than 640 kibibytes (KiB) of "conventional memory". The 640KiB limit was specific to the IBM PC and close compatibles; other machines running MS-DOS had different limits, for example the Apricot PC could have up to 768KiB and the Sirius Victor 9000, 896KiB. Memory management on the IBM family was made complex by the need to maintain backward compatibility to the original PC design and real-mode PC DOS (MS-DOS), while allowing computer users to take advantage of large amounts of low-cost memory and new generations of processors. Since MS-DOS has given way to Microsoft Windows and other 32-bit operating systems not restricted by the original arbitrary 640KiB limit of the IBM PC, managing the memory of a personal computer no longer requires the user to manually manipulate internal settings and parameters of the system.

The 640KiB limit imposed great complexity on hardware and software intended to circumvent it; the physical memory in a machine could be organised as a combination of base or conventional memory, upper memory, high memory (not the same as upper memory), extended memory, and expanded memory, all handled in different ways.

Read more about DOS Memory Management:  Conventional Memory, Upper Memory Area, Expanded Memory, The 80286 and The High Memory Area, 80386 and Subsequent Processors, Extended Memory

Famous quotes containing the words dos, memory and/or management:

    “It is part of the nature of consciousness, of how the mental apparatus works, that free reason is only a very occasional function of people’s “thinking” and that much of the process is made of reactions as standardized as those of the keys on a typewriter.”
    —John Dos Passos (1896–1970)

    “Beauty sat bathing by a spring,
    Where fairest shades did hide her;
    The winds blew calm, the birds did sing,
    The cool streams ran beside her.
    My wanton thoughts enticed mine eye
    To see what was forbidden:
    But better memory said Fie;
    So vain desire was chidden—”
    —Anthony Munday (1553–1633)

    “Why not draft executive and management brains to prepare and produce the equipment the $21-a-month draftee must use and forget this dollar-a-year tommyrot? Would we send an army into the field under a dollar-a-year General who had to be home Mondays, Wednesdays and Fridays?”
    —Lyndon Baines Johnson (1908–1973)