Windows 3.1: Insufficient Memory Error on a 2-MB Machine

• Microsoft Windows operating system versions 3.1, 3.11

SUMMARY

If you run the Microsoft Windows operating system version 3.1 in 386 enhanced mode, Windows cannot run a 640K MS-DOS prompt on a machine with only 2 MB of memory. If you attempt to do this, Windows generates the following error message:

   Insufficient memory for application requested space, decrease PIF KB
   required and try again.

Note: Some machines cannot create permanent swap files and enable 32-bit disk access because of hardware limitations. On machines with these limitations, you must add more memory or reduce the memory requirements for the virtual machines (VMs).

MORE INFORMATION

Reducing the Memory Requirements in DOSPRMPT.PIF

DOSPRMPT.PIF has the KB Required and the KB Desired values set to -1 by default. This tells Windows the VM must be as large as possible. If there is insufficient memory available to create a 640K VM, Windows returns the aforementioned error message.

In Windows 3.0, the equivalent program information file (PIF) has settings of 384 for KB Required and 640 for KB Desired. These settings allow a VM with less than 640K of conventional memory.

If you choose to reduce the memory settings for the MS-DOS prompt in Windows 3.1, change the value for KB Required to 128 and the value for KB Desired to 640 using the PIF Editor.

Reducing Memory Requirements for All MS-DOS Applications

You can reduce the memory requirements for all MS-DOS applications that you run in Windows 3.1 with the use of the WindowsKBRequired and WindowMemSize settings in the [386 Enh] section of the SYSTEM.INI file. Use equal settings for these two settings to ensure that Windows accepts the values as valid. Settings of 400 should allow a VM to be run in Windows 3.1 on a 2-MB machine, even if a PIF has a -1 setting for KB Desired and KB Required. The following section is taken from the Windows Resource Kit (WRK) SYSINI.WRI file:

   ============================================================
   WindowKBRequired=<kilobytes>
   Default:  256
   Purpose:  Specifies how much conventional memory (in
             kilobytes) must be free in order to start Windows.
   To change:  Use Notepad to edit the SYSTEM.INI file.
   ============================================================
   WindowMemSize=<number-or-kilobytes>
   Default:  -1
   Purpose:  Limits the amount of conventional memory Windows
             can use for itself. The default value (-1)
             indicates that Windows can use as much
             conventional memory as it needs. If there is not
             enough memory to run Windows in 386 enhanced mode,
             try entering a positive value less than 640.
   To change:  Use Notepad to edit the SYSTEM.INI file.
   ============================================================