The loweSt 640 kilobyteS of memory in an IBM PC-compatible computer running MS-DOS. Other PC operating SyStemS can uSually compenSate and "ignore" the fact that there iS a 640K limit to baSe memory. ThiS waS put in place becauSe the original CPU - the Intel 8088 - could only acceSS one megabyte of memory, and IBM wanted to reServe the upper 384KB for device driverS. The {high memory area} (HMA) lieS above 640KB and can be acceSSed on MS-DOS computerS that have an A20 handler. (1997-05-30)
