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Q139157: HOWTO: Reducing RAM Memory to Test Visual FoxPro Applications

Article: Q139157
Product(s): Microsoft FoxPro
Version(s): 3.0
Operating System(s): 
Keyword(s): kbenv kbvfp kbvfp300 kbvfp600
Last Modified: 12-AUG-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 6.0 
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SUMMARY
=======

In previous versions of FoxPro, you could limit the amount of memory available
to FoxPro by including a MEMLIMIT statement in the FoxPro configuration file.
Visual FoxPro no longer uses the MEMLIMIT statement. Visual FoxPro dynamically
allocates memory as it is needed; therefore the total amount of memory that
Visual FoxPro is using varies at any given time.

When testing a Visual FoxPro application, you may need to test the application on
systems that have varying amounts of memory. This is particularly important when
determining the system requirements (memory requirements) for a Visual FoxPro
application. The only way to limit the amount of memory available to Visual
FoxPro is to limit the amount of memory available to the operating system, so
the method used to limit the memory available to Visual FoxPro will vary
depending on the operating system.

MORE INFORMATION
================

Windows NT
----------

To limit the amount of memory available to Visual FoxPro running under Windows
NT, you need to edit the Boot.ini file. The Boot.ini file specifies start up
options for Windows NT. It is located in the root directory of the boot drive.
The /MAXMEM switch is an undocumented switch that allows you to specify the
maximum amount of RAM memory that Windows NT will use. This switch is placed at
the end of the ARC path in the [Operating System] section of the Boot.ini file.
The following example forces Windows NT to use only 10 MB of RAM:

     multi(0)disk(0)rdisk(0)partition(1)\winnt= Windows NT /MAXMEM=10


Windows 95, Windows 3.x, and Windows for Workgroups 3.x
-------------------------------------------------------

These operating systems do not provide a way to limit the amount of memory
available. To limit the amount of memory available to these operating systems,
you must allocate extended memory to something else to make it unavailable to
the operating system. The easiest way to do this is to set up a RAM drive. A RAM
drive uses the computer's RAM memory to simulate a disk drive. Once this memory
is allocated to the RAM drive, it is unavailable to any other part of the
operating system, including Visual FoxPro. A RAM drive is created by loading the
Ramdrive.sys device driver in the Config.sys file. If the system had 16 MB of
RAM, and you want to limit the amount of available memory to 10 MB, create a 6
MB Ram drive. Adding the following line to the Config.sys file will create a 6
MB RAM drive:

     DEVICE=C:\WINDOWS\RAMDRIVE.SYS 6144 /E

For more information on creating a RAM drive, please consult your Windows or
MS-DOS documentation.

Additional query words:

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Keywords          : kbenv kbvfp kbvfp300 kbvfp600 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP600
Version           : 3.0
Issue type        : kbhowto

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