From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Newsgroups: comp.os.msdos.programmer,comp.os.msdos.djgpp
Subject: Re: Is DOS dead?
Date: Thu, 16 Mar 2000 17:27:11 +0200
Organization: NetVision Israel	
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On Thu, 16 Mar 2000, Michael Tippach wrote:

> > > > > it takes 3 more lines of assembly code to detect NT.
> > > >
> > > > That's not really true, especially now that you need to distinguish
> > > > between NT and W2K.
> > >
> > > So does W2K return a different value than 0x3205 from function 0x3306?
> > 
> > No, it reports the same value, but behaves differently.
> 
> In how far does it behave differently? Could this different behaviour be
> used to detect either version or is there no way to, by means of code,
> inspect the differences without crashing the NTVDM on one system?

No, I don't know about any way of telling NT and W2K apart without 
crashing the system.  This test is required *because* different 
work-arounds are needed in each case to avoid crashes and other 
``surprises''.

One problem with NT that needs to be worked around is that NT ignores the 
hight 16 bits of the user procedure address that is installed as a 
real-mode  callback (e.g., for handling mouse events).  One problem with 
W2K that needs to be worked around is that nested DPMI (well, DJGPP, to be 
precise) programs crash NTVDM; the reason for the latter problem is still 
unknown at this time.