Date: Tue, 30 Aug 94 17:02:40 -0400
From: dj AT ctron DOT com (DJ Delorie)
To: OKRA AT max DOT tiac DOT net
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: TSRs?

>   Sorry but I've never really figured out what dpmi is.  You only get it 
> under Windows or OS/2 or something, right?  What if I'm not under dpmi?  
> Does that make it easier or harder?  EMM386 is a TSR that I assume uses 
> at least a little bit of protected mode, and it runs under plain DOS and 
> Windows.  How does EMM386 do it?

DPMI is a protected mode interface, much like DOS's int21 is an
operating system interface.  DPMI has a set of functions that turn
your program into a TSR.  go32's dpmisim doesn't support those
functions, and even when using real dpmi, go32 will crash if you try
to take advantage of them.

EMM386 uses protected mode.  GO32 uses protected mode.  EMM386 is a
TSR.  GO32 is not.  It's not a matter of easy or hard, go32 just
doesn't know how to deal with a program that wants to be a TSR.