Upper Memory Area

The way that the PC organizes its use of memory is somewhat confusing--welcome to the most confusing part of that confusion. :^) The upper 384 KB of the first megabyte of system memory, directly above conventional memory, is called the upper memory area or UMA, and it is a very busy place. Confusion abounds regarding this important part of memory. It is important because it is the cause of many system configuration problems, and because it is one of the key enabling factors in allowing you to free up conventional memory for program use.