DOS Protected Mode Interface
(DPMI) The method which Microsoft
prescribes for a DOS
program to access extended memory
under a multitasking
environment, e.g. Microsoft Windows
This service is provided by the HIMEM.SYS driver on IBM PC
The DPMI specification was finalized in 1990.
The specification itself is available from Intel Literature Sales
VCPI (Virtual Control Program Interface), which was an alternative, and incompatible method for doing the same thing.
["Windows 3.1 Secrets", Brian Livingston, 1992, ISBN 1-878058-43-6, pages 280-281 and 302].