Vista - Cannot get DOS program (1992 Foxpro) to work

A couple of things.

The A20 handler being different. DOS would "guess" at the correct one, but
not always get it right. You could try forceing one:

http://support.microsoft.com/kb/96711

WARNING: Have a boot disk, real or virtual, in case forceing one locks the
VM.

Your Expanded Memory Page Frame, the point in conventional memory that is
used as a "swap frame" is in a different location. This may be because the
VM uses E000 for a BIOS extension, or the Video BIOS. It's not specified in
the BIOS, but it does seem to be in use for something.

Foxpro may be trying to use this memory directly, and is causing the error.
You might be able to tweak the settings for EMM386.EXE.

http://support.microsoft.com/kb/78557

PC Magazine used to have a program, UMASCAN that would map the area of
memory above 640K and tell you what was there.
The only place I can find it on the 'net is in a ZIP file here:

http://www.programmersheaven.com/dow.../download.aspx

Good luck.

Ferd

"Ed Davis" <Ed Davis@xxxxxx> wrote in message
news:51F0BC88-A79C-4AD8-8648-1BF6694F7047@xxxxxx

I have a 1992 version of Foxpro:

FoxPro/LAN 2.0 EXE Support Library (X)
(c) 1989-1992 Microsoft Corporation
Worldwide Edition
(Demand Paging Enabled)

Dos Extension Technology Copyright 1988-1990,
ERGO Computing, Inc. All Rights Reserved.

When I run it under Virtual PC, Foxpro crashes with:

GP at 0020 0000 5E83 0024
Interrupt 0D at CS:EIP=0510:0759001F

It works fine under the following setup on a real machine:

Windows 98, but just boot DOS. Output of the version command:

Windows 98 [Version 4.10.2222]

autoexec.bat - only includes a path statement
config.sys:
dos=high,umb
devicehigh=c:\dos\himem.sys /testmemff
devicehigh=c:\dos\emm386.exe
files=99

In addition, the following config.sys also works:
same as above, remove the emme36.exe line, and replace the
himem.sys line with:

devicehigh=c:\dos\himem.sys /testmemff /int15=4800

According to the mem command, I have 131,648k of total memory.

I've set up a virtual machine under Virtual PC, trying to make it
as close as I can to the real machine. The autoexec.bat and
config.sys are identical. The virtual machine is running Windows
98 DOS, same version as the real machine.

Here are the differences I have noted:

Booting message differences:

In the real machine:

Installed A20 handler number 1.

In the virtual machine

Installed A20 handler number 2.

mem message differences (under Memory Type):

In the real machine:

Reserved: 384k total 384k used 0k free

In the virtual machine

Reserved: 0k total 0k used 0k free

pmap (old Chris Dunford DOS mem-like utility) message differences
(under Expanded memory summary):

In the real machine:

Page frame segment: E000h

In the virtual machine

Page frame segment: D000h

I wonder if these differences are what is causing the problem?
Any ideas how I can make the two machines more alike?

Interestingly, both machines (the real and the virtual) have AMI
BIOS's - the real one dated 1996, and the virtual one dated 2006.

Thanks for any help.

btw. int 0xd is Memory Access Violation error. Are you sure that FoxPro
executable isn't damaged?

Ed Davis > schrieb in Nachricht
<51F0BC88-A79C-4AD8-8648-1BF6694F7047@xxxxxx>...

I ran CRC32 on the 3 executable files:
foxr.exe, foxswap.com, and foxprox.esl

Comparing the ones in the VPC and the ones on the real machine.
They were the same.

But this definitely was something good to make sure of.


"st" wrote: