Date: Wed, 16 Nov 94 09:25:07 -0500
From: dj AT stealth DOT ctron DOT com (DJ Delorie)
To: MRMILLER AT delphi DOT com
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Virtual memory and DPMI (and Win 3.1)

> Normal DOS:
> ===========
>     default:    fails after allocating approx 4 Mb with the 
>                   message "DPMI: Not enough memory"
>     nodpmi:     ran sucessfully
>  
> Win DOS box:
> ============
>     default:    ran sucessfully
>     nodpmi:     won't run at all with some message about being in V86
>                   mode
>  
> Isn't virtual memory suppose to work, regardless of the presence of
> dpmi (assuming you have the disk space)?  Is there some way to set GO32
> so that the program would work whether or not it was run from a Windows
> DOS box or not?

Virtual memory in DPMI mode is limited by the amount of virtual memory
that the DPMI provider is willing to give you.  For qdpmi, this is the
MAXMEM option.  I think it defaults to 4Mb.

In Windows, the ONLY api available is DPMI, so if you disable dpmi,
there is no way to enter protected mode.