High Memory Area
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High Memory Area IBM PC/AT- ( ). 65520 ( 64 KiB 16 ).
«HMA» Microsoft, , . «High Memory Area» . Microsoft HMA «High Memory Arena».
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Intel 8086 Intel 8088 : 16- («») 16-
- () × 16 + ().
20- 1 (220 ) , 0000:0000 FFFF:000F. FFFF:0010 FFFF:FFFF 21-:
- FFFFh × 16 + 0010h = 100000h,
- FFFFh × 16 + FFFFh = 10FFEFh,
, 21- , , FFFF:0010 , 0000:0000.
Intel 80286/80288 24- ( 224 = 16 ), .
IBM PC/AT Intel 80286, IBM PC IBM PC/XT, Intel 808x, (), 21- (A20) . (Gate A20 (.).) ( Intel 8042) .
-, A20 handler, , , 1024 1088 .
[] MS-DOS
HMA Microsoft Windows 2.1 ( MS-DOS) 1988 A20 handler HIMEM.SYS.
1991 MS-DOS 5.0, HMA , 46 . MS-DOS . HIMEM.SYS MS-DOS.
DOS HMA, CONFIG.SYS :
device = HIMEM.SYS dos = high
HMA DOS HIMEM.SYS, HMA DOS .
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. Upper . . High . Upper Memory Area (Upper Memory Block) High Memory Area.
, UMB HMA. UMA .
