How, When, and Why to Use MONOUMB and MONOUMB2.386 (93680)

The information in this article applies to:
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft Windows 3.1
    Microsoft Windows for Workgroups 3.1

This article was previously published under Q93680
3.10     | 6.00 6.20 6.21
kbusage kbdisplay


This article discusses the MONOUMB virtual device drivers (MONOUMB.386 and MONOUMB2.386) and the differences between them.


The MONOUMB virtual device drivers (VxDs) work around problems with Windows video display drivers (VDDs) written for Windows 3.0 with the Windows 3.0 Device Development Kit (DDK). Windows 3.0 VDD VxDs always claim the B000-B7FF memory region, even when they don't use it.

Windows checks the installed expanded memory manager (EMM) and loads a "VDD_2" VxD if it's present; this allows Windows to use the B000-B7FF region. 386Max and BlueMax both contain the VDD_2 VxD. However, because they don't implement VDD_2 correctly, they require MONOUMB2.386 to patch it.

QEMM and EMM386 do not contain the VDD_2 VxD, and therefore require MONOUMB.386 (the complete VDD_2 VxD).

Using MONOUMB.386 or MONOUMB2.386

If you are using a Windows 3.0 VDD under Windows 3.1, you get the following error message when you start Windows:

Windows cannot set up an upper memory block at segment B000. Exclude this address space by using the syntax of your memory manager. For more information, see the README.WRI file. Type WIN /S to start Windows in standard mode and choose the Read Me icon.
If the VDD is not using the B000-B7FF range, you can install MONOUMB.386 or MONOUMB2.386 to make more memory available to Windows.

If you are using QEMM or EMM386.EXE, add the following line to the [386enh] section of your SYSTEM.INI file:


If you are using 386Max or BlueMax, add the following line to the [386enh] section of your SYSTEM.INI file:


Where to find MONOUMB.386 and MONOUMB2.386

MONOUMB.386 is provided with Windows version 3.1 and MS-DOS versions 6.0, 6.2, and 6.21. MONOUMB2.386 is provided with Windows version 3.1 and Windows for Workgroups version 3.1. Windows version 3.11 and Windows for Workgroups version 3.11 do not include either MONOUMB.386 or MONOUMB2.386.

Modification Type: Major Last Reviewed: 11/26/2003
Keywords: KB93680