How the Extended (32-Bit) Version of FoxPro Uses Memory

ID: Q121079

The information in this article applies to:

Microsoft FoxPro for MS-DOS, versions 2.5x, 2.6, 2.6a

SUMMARY

The "Installation & Configuration Guide" makes several incorrect and misleading statements about how the Extended (32-bit) version of FoxPro for MS-DOS makes use of memory.

MORE INFORMATION

Page 3-7 of the "Installation & Configuration Guide" states:

   The Extended version of FoxPro can take advantage of extended memory
   or extended memory that has been made to act like expanded memory, but
   it cannot mix and match the two.

This sentence makes it sound like FoxPro will only use certain types of memory depending on how the memory is configured.

FoxPro actually will take all the memory it finds, no matter what form it is in, and convert it all to XMS/DPMI memory. It does this through its internal memory manager, which is a modified version of the Phar Lap DOS extender.

The example in the second paragraph on page 3-7 is also incorrect. It should say that FoxPro will find and convert all 8 MB of memory to XMS/DPMI and use all 8 MB of memory.

In addition, page 3-7 also shows an alert box that states:

   When trying to use both DPMI and VCPI, the Phar Lap DOS extender
   uses only VCPI.

This is statement is incorrect. If FoxPro finds both types of memory, it will convert all the VCPI-compliant memory to XMS/DPMI memory.

Additional reference words: FoxDos 2.50 2.50a 2.50b 2.60 2.60a extended memory usage dpmi vcpi docerr KBCategory: kbenv kbdocerr KBSubcategory: