Architects, Lotus Development Corp., Quadram, Qualitas and Rational Systems, VCPI is provided by an expanded memory manager in DOS (e.g. CEMM, QEMM, later EMM386) and does allow 80386 protected-mode DOS extenders to coexist with 80386 EMS expanded memory emulators.
(This was typically accomplished through a memory manager operating as a virtual [mode] control program for the processor.)
Between 1989 and February 1990[7] an alternative specification was proposed under the name Extended VCPI[8][9][10] (XVCPI[8][9][11]) by a number of companies including Intel's Software Focus Group,[7][9][10] Lotus,[7] Digital Research,[7] Interactive Systems, Viewport International and others to address some of the shortcomings of VCPI and better exploit the memory management and multitasking capabilities of the 386 processor.
[nb 1] Since February 1990[7] these efforts ultimately succumbed to the (parallel) development and publication of the DPMI specification in May 1990, which addressed similar problems, but was compatible with the implementation of Microsoft Windows 3.0 to be released the same year.
In February 1991, the Multiuser DOS Federation (MDOS), an initiative formed in July 1990,[12] issued a statement regarding their support of DPMI.