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)
