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Re: Q: optimal swap file settings with win3.11

  • To: mathgroup at
  • Subject: [mg3907] Re: Q: optimal swap file settings with win3.11
  • From: ianc (Ian Collier)
  • Date: Sun, 5 May 1996 23:12:22 -0400
  • Organization: Wolfram Research, Inc.
  • Sender: owner-wri-mathgroup at

In article <4luue9$3u8 at>,
vrossum at (M.C.W._van Rossum) wrote:

> Hi, 
> I'm using mma 2.2.1 with windows3.11 and 16 mb ram.
> Often, when doing large calculations, mma quits kernel due to lack of memory,
> despite a large swapfile (48 mb) and giving 24 mb extra to the kernel.
> It seems mma runs into other limitations than memory.
> Indeed 1) the memory meter shows still lots of free memory
> 2) a smaller swap file works just as good
> So what are the optimal settings for swap file size,
> ExtraPages (math.ini) and PagesOverCommit ( system.ini) ??
> Any comments welcom,
> Mark

Without knowing exactly what you are doing I cannot be certain, 
but I suspect that this is a limitation of your version of 
Mathematica not a problem with how you have virtual memory 

The version of Mathematica that you are using is able to address
a total of 16 MB of RAM. About 4 MB of that is taken up by the 
front end and loading the kernel. The setting for "Kernel Extra
Memory" that you are using is only able to usefully allocate an 
additional 12 MB (despite the fact that apparently allows you to 
allocate more). This 12 MB is the space available to the kernel 
to perform computations.

If your computations regularly cause the kernel to run out of
memory then the best thing I can suggest is that you upgrade to
the current version of Mathematica for Windows (2.2.3). In this
version the front end and kernel are separate applications. The 
kernel is a Win32s appllication. It uses the Win32s libraries to
allow the kernel to address more than one 16 MB memory segment. 
This will allow you to complete computations that cause your
version of Mathematica to run out of memory.

In addition to this enhanced memory usage version 2.2.3 also 
supports MathLink, Mathematica's inter-application communication 

For information about upgrading contact info at

I hope this helps.


Ian Collier
Wolfram Research, Inc.
tel:(217) 398-0700   fax:(217) 398-0747    ianc at
Wolfram Research Home Page:


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