(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 PCs. 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.