QDPMI is Quarterdeck's True DPMI host. Actually the DPMI host was written by
Ergo, though, and Quarterdeck merely put a pretty face on it. Since a True DPMI
host is really a DOS extender, Ergo was perfectly fit to write one. So QDPMI is
just a version of Ergo's DPMI host, their DPM16 and DPM32 products being other
versions. QDPMI is tied to QEMM-386 only by this version of the Ergo DPMI host
being only able to run on a 386 with VCPI (not starting in real mode and
allocating extended memory by other means) and by QDPMI.SYS checking for
QEMM-386. If this check is removed QDPMI can work with any 386 memory manager
that supports VCPI.

QDPMI.SYS is the resident "driver" that hooks INT 2Fh and provides the
INT 2Fh/AX=1687h interface, and QDPMIVM.OVL is the actual DPMI host that is
loaded and run when someone calls the real to protected mode switch entry
point.

QDPMIANY.SYS is a hacked version of QDPMI.SYS with the check for QEMM-386
removed.

QDPMIXFL.DOC (Word v6.00 format) contains my notes on reverse-engineering
QDPMI.SYS.

Have fun!

Michael Sokolov
msokolov@ivan.Harhan.ORG
2003-04-19