VCPI-DPMI

12/12/98

VCPI/DPMI - Virtual Control Program Interface/DOS Protected Mode Interface -- A 80386 Memory management standard for memory above 1mb created by Phar Lap with the collaboration of other software developers. VCPI has been largely replaced by Microsoft's DOS Protected Mode Interface (DPMI) Interface.

DPMI provides a more extensive memory model than VCPI and is compatible with Unix, 386 Enhanced Mode Windows, etc. Unlike VCPI, DPMI can be used with 80286 computers.

VCPI provides MSDOS programs running on an 80386 or above computer with a method of accessing extended memory (memory with addresses above 1mb). 80386 Extended memory managers such as EMM386, QEMM, 386MAX support the VCPI interface to DOS extension software via an elaborate set of Interrupt calls based on INT 2F.

VCPI supports both extended and expanded memory. It is intended to support MSDOS applications and to allow multiple users to coexist under the extended mode memory manager. VCPI will not work with 386 Enhanced mode Windows. When setting up older MSDOS programs, it may be necessary to research whether support for VCPI, DPMI or neither is required. Some applications require a /NOVCPI switch be used with EMM386 to prevent VCPI from being used.

For an extensive discussion of memory management, refer to:

http://web.archive.org/web/19980624123308/http://www.taxprep.com/support/ms_ory.html

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