UMA
(1) (Unlicensed Mobile Access) See GAN.
(2) (Upper Memory Area) Memory in a PC between 640K and 1M. More relevant in the days of DOS, this region was broken into Upper Memory Blocks (UMB) reserved for video memory and other peripherals. Because people wanted to run larger applications that took up much of the lower 640K, a variety of different memory managers became available to load and manage drivers and TSRs into unoccupied UMA blocks. EMM386, which came with DOS 5 and Windows 3.0, was an example of such software. See DOS EMM386.EXE and QEMM.
Memory Allocation in a PC