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Re: Kernel Memory

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  • Subject: [mg1965] Re: [mg1957] Kernel Memory
  • From: John Fultz <jfultz>
  • Date: Sun, 27 Aug 1995 23:24:31 -0400

> Can someone explain:
>    In the Options menu under Kernel...
>    The Run Kernel in background option (when selected lets you run/access other
> windows applications while you have Mathematica going)
>    My question is what do you do with the Kernel File... button and why?
> I'm having problems running out of Kernel Memory (have Kernal extra memory set
> to 12288, the max)
> thanks
> Robert
> - 
> ------------------------------------------------------------------
> 			      Robert W. Fuentes
> 		 Lockheed Martin - Tactical Aircraft Systems
> 		      Mission Planning Systems 068-3800
> 	       PO Box 748, Ft. Worth, TX. 76101, Mail Zone 5975
> 		   Voice: 817-763-7530   FAX: 817-777-0473
> 		     EMail: robert at
> 		      LMTAS MS-Mail:  FNTSRWAA@smtpgate

The Kernel File button would be used if you had multiple kernels (say a
2.1 kernel and a 2.2.1 kernel) which you might want to access.  Not
terribly useful, really, and it's also obsolete now that later versions
of Mathematica (e.g. 2.2.2, 2.2.3) use MathLink to communicate with a
standalone kernel program instead of launching the kernel as an "EXP"
file like 2.2.1 does.

In Mathematica 2.2.1 and earlier for Windows, the maximum memory you
could allocate to the kernel for data storage was 12 megabytes.  This
limitation was due to a number of factors I won't go into (unless
someone's really interested, that is), but due to the new MathLink and
standalone kernel design, the more recent versions do not have a 12
megabyte limit.  The only existing limit now, outside of the Windows
limit for addressing memory (which I don't recall off the top of my
head) is that you cannot create or manipulate a single data structure
which requires more than 16 megabytes to store.

My suggestion to you would be to either find a way to save memory with
your calculations (tricks like clearing the command history and unused
variables), or to upgrade to Mathematica 2.2.3, where you needn't worry
about this limitation.

If you'd like to upgrade, you can contact Wolfram Research at
1-800-441-6284 or e-mail to orders at  Be prepared to have your
license number ready so they know you're a registered user.

John Fultz
Wolfram Research, Inc.

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