Registry Entries for NT Virtual DOS Machine (VDM):

Last reviewed: May 8, 1997
Article ID: Q102059

The information in this article applies to:
  • Microsoft Windows NT operating system, version 3.1
  • Microsoft Windows NT Advanced Server, version 3.1

SUMMARY

This article covers the registry entries for Windows NT virtual DOS machines (VDMs).

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Control\VirtualDeviceDrivers

This registry entry contains all the virtual device drivers (VDDs) that are loaded in the VDM at initialization. This is entry is mainly intended for independent hardware vendors (IHVs) who want to provide virtual device drivers with their native device drivers. By default, this entry does not have any VDDs.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\WOW

This registry entry supports the following keys:

  • cmdline: The command line which NT uses to create NT virtual
                    DOS machines (VDMs) for MS-DOS-based applications.
                    This entry is not useful for end users in any way.
    
    
  • size: This tells NT what should be total memory size for
                    the VDM created for MS-DOS-based applications. This
                    includes conventional and extended memory. Default
                    value is 0, which means NT should choose the size
                    depending on the machine configuration. If this value
                    is altered, NT uses it rather than determining a value
                    itself.
    
    
  • wowcmdline: Same as cmdline described above but used by Windows on
                    Windows (WOW) VMDs.
    
    
  • wowsize: same as size described above but used by WOW VDMs.
  • KnownDLLs: This is only for WOW applications. If a DLL name is
                    included in this entry and the application loads it
                    without specifying the full path, the WOW subsystem
                    loads that DLL from the Windows NT system directory
                    (\SYSTEM32). This ensures the Windows NT loads a
                    specific version of the WOW DLL rather than the
                    application's version of that DLL (since the
                    application's version of the DLL may not work under
                    Windows NT.
    
    
  • LPT_Timeout: This is used by MS-DOS-based applications. There is no
                    specific call to tell MS-DOS that the print job has
                    completed. Under Windows NT (which spools print jobs),
                    it is important to close the print job for printing to
                    start. NT VDMs uses this timeout value to detect no
                    printing activity before closing the print job handle.
                    The default value is 15 seconds.
    


Additional query words: prodnt
Keywords : kbprint nt16ap ntdosap ntprint NTSrvWkst
Platform : WINDOWS


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Last reviewed: May 8, 1997
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