XMS - Computer Definition
(1) See cross memory services.
(2) (eXtended Memory Specification) A programming interface that allowed DOS programs to use memory above 1MB in 286s and up. It provided functions to reserve, release and transfer data to and from extended memory and the high memory area (HMA). XMS allowed data and programs to be "stored" in, but not "run" in, extended memory. See extended memory, HMA, HIMEM.SYS, VCPI and DPMI.