| high memory area (HMA) The first 64 (minus 16 byte) of the on an . By a strange design glitch the processors can actually address 17*64 kbyte minus 16 byte of memory (from 0000:0000 to ffff:ffff) in real mode. In the and processors, unable to handle more than 1 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 can control the addressing mode dynamically, thereby allowing programs to load themselves into the 1024--1088 kbyte region and run in . From version 5.0 parts of can be loaded into HMA as well freeing up to 46 kbytes of . (1995-01-10) |
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