Topic summary
Enhanced EMS
Extracted from the Wikipedia article Expanded memory.
Expanded Memory Specification (EMS)
Quadram, AST, and Ashton-Tate created the Enhanced EMS (EEMS) standard. EEMS, a superset of EMS 3.2, allows any 16 KiB region in lower RAM to be mapped to expanded memory, as long as it was not associated with interrupts or dedicated I/O memory such as network or video cards. Thus, entire programs can be switched in and out of the extra RAM. EEMS also added support for two sets of mapping registers. These features are used by early DOS multitasker software such as DESQview. 1987's LIM EMS 4.0 specification incorporated practically all features of EEMS.