Using VCPI Programs with Windows

Article translations Article translations
Article ID: 81493 - View products that this article applies to.
This article was previously published under Q81493
This article has been archived. It is offered "as is" and will no longer be updated.
Expand all | Collapse all


Many MS-DOS-based applications use the Virtual Control Program Interface (VCPI) specification to directly access protected-mode extended memory on an 80386 or 80486 computer. These programs do not work with Microsoft Windows version 3.0 in 386 enhanced mode. They work in Windows in real mode and may work in standard mode. Windows uses a newer standard called DOS Protected Mode Interface (DPMI).

DPMI is a multitasking version of VCPI with a few other enhancements. Many software companies have already announced plans to support DPMI in future releases of their products. If you experience difficulties running an MS- DOS-based application in standard or enhanced mode of Windows, check with the MS-DOS-based-application manufacturer to see if it now supports the DPMI specification.


The following switch can be entered into the SYSTEM.INI file in the [386Enh] section to turn off the warning message that appears when an MS-DOS-based application attempts to use VCPI:
NOTE: Changing this switch does not allow the application to run. It merely suppresses the warning message if you attempt to run one of these applications.

The following is a partial list of applications that use the VCPI specification to access extended memory:
   Application                          Vendor
   Lotus 1-2-3 release 3.0              Lotus
   Interleaf Publisher                  IBM
   Autocad 386                          Autodesk
   Paradox 386                          Borland
   FoxBase+ 386                         Microsoft
   Smalltalk 80 386                     ParcPlace
   Common Lisp CLOE-386                 Symbolics
   Laboratory Microsystems UR/Forth     STSC
   APL Plus II                          STSC
   VM/386                               Intelligent Graphics Corporation
   Concurrent DOS 386                   Digital Research
   PC-MOS/386                           The Software Link
Lotus has announced that version 3.1 will follow the DPMI specifications and will run under all three modes of Windows 3.0.

PC-MOS is a multitasking operating environment similar to Windows/386. You cannot run Windows under PC-MOS because Microsoft Windows/286, Windows/386, and Windows 3.0 and 3.1 are all protected-mode software competing for the same resources.

The following is a list of 386 memory managers that use the VCPI specification and are incompatible with Windows 3.0 running in enhanced mode:
   Memory Manager                       Vendor
   ILIM386.SYS                          Intel
   Soft Bits 386                        Soft Bits
   CEMM                                 COMPAQ Computer Company
   QEMM                                 Quarterdeck Office Systems
   386-to-the-Max                       Qualitas
Most of the companies listed above are also planning versions of their applications that will use the DPMI specification.


Article ID: 81493 - Last Review: February 27, 2014 - Revision: 2.2
  • Microsoft Windows 3.0 Standard Edition
  • Microsoft Windows 3.1 Standard Edition
  • Microsoft Windows 3.11 Standard Edition
kbnosurvey kbarchive KB81493

Contact us for more help

Contact us for more help
Connect with Answer Desk for expert help.
Get more support from