Dictionary: A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z

High memory area

(HMA) The first 64 kilobytes (minus 16 byte) of the extended memory on an IBM PC. By a strange design glitch the Intel 80×86 processors can actually address 17*64 kbyte minus 16 byte of memory (from 0000:0000 to ffff:ffff) in real mode. In the Intel 8086 and Intel 8088 processors, unable to handle more than 1 megabyte of memory, addressing wrapped around, that is, address ffff:0010 was equivalent to 0000:0000. For compatibility reasons, later processors still wrapped around by default, but this feature could be switched off. Special programs called A20 handlers can control the addressing mode dynamically, thereby allowing programs to load themselves into the 1024–1088 kbyte region and run in real mode. From version 5.0 parts of MS-DOS can be loaded into HMA as well freeing up to 46 kbytes of conventional memory.


Read Also:

  • High-milling

    noun 1. a process for making fine flour, in which the grain is alternately ground and sifted a number of times.

  • High-minded

    [hahy-mahyn-did] /ˈhaɪˈmaɪn dɪd/ adjective 1. having or showing high, exalted principles or feelings. adjective 1. having or characterized by high moral principles 2. (archaic) arrogant; haughty adj. c.1500, “arrogant;” 1550s, “morally lofty,” from high (adj.) + minded. Related: High-mindedness.

  • High moby

    /hi:’ mohb’ee/ The high half of a 512K PDP-10’s physical address space; the other half was of course the low moby. This usage has been generalised in a way that has outlasted the PDP-10; for example, at the 1990 Washington D.C. Area Science Fiction Conclave (Disclave), when a miscommunication resulted in two separate wakes being […]

  • High-muck-a-muck

    [hahy-muhk-uh-muhk, -muhk-uh-muhk] /ˈhaɪˌmʌk əˈmʌk, -ˈmʌk əˌmʌk/ noun 1. an important, influential, or high-ranking person, especially one who is pompous or conceited. noun 1. a conceited or haughty person

Disclaimer: High memory area definition / meaning should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. All content on this website is for informational purposes only.