This article discusses how Microsoft Windows version 3.1 determines the
file size to recommend for swap files.
Temporary Swap File
- Q. What is the temporary swap file recommended maximum size?
A. It is four times the physical RAM in the computer, rounded to the
next 4 megabytes (MB). For example, if you have 3 MB of free XMS
memory, you can create 16 MB of virtual memory ([3 MB * 4] + 4MB = 16
MB). Four is the default value for the SYSTEM.INI [386Enh] switch
The recommended maximum size is also limited by the "50 percent free
hard drive space" rule (that is, a swap file cannot take more than 50
percent of the available, usable hard drive space [compressed or
stacked hard drive space is not considered usable]).
Whichever limit is reached first establishes the maximum size.
Q. When I set a temporary swap file to a size larger than the
maximum recommended size, the following error message is displayed.
What does this message mean?
A. WIN386.EXE creates the temporary swap file at run time, and the
file grows as necessary; the swap-file functionality only controls the
maximum size allowable. You can never exceed 50 percent of the free
hard disk space or four times the amount of physical RAM.
Windows will not use more than the virtual memory specified by
the Recommended Size. Are you sure you want to create a larger
Permanent Swap File
- Q. When I set a permanent swap file to a size larger than the
recommended maximum size, Windows forces the setting back to the
recommended maximum size, even when plenty of free hard drive space
exists. When this occurs, the following message is displayed. What
does this message mean?
A. When Windows sets up a permanent swap file, free and contiguous
hard drive space limits the recommended maximum size. A permanent swap
file must be located on unfragmented space; therefore, even if there
is plenty of disk space, the swap file is limited by file
The number you specified is too large. The number currently
displayed is the largest you can specify.
If you have an disk-optimization program, such as Speedisk by Norton
Utilities or Compress by PC Tools, you can use it to make more of the
free hard drive space contiguous and usable for a permanent swap file.
NOTE: The maximum size limitations described in the first answer apply
in addition to the required unfragmented disk space.
NOTE: These utilities should not be run from Windows and should not be
run if you are using a disk cache. For more information, consult the
manual for the utility you are using.
KBSubcategory: wfw win31 wfwg
Article ID: 83968 - Last Review: November 26, 2003 - Revision: 2.0
- Microsoft Windows 3.1 Standard Edition
- Microsoft Windows 3.11 Standard Edition
- Microsoft Windows for Workgroups 3.1
- Microsoft Windows for Workgroups 3.11