Date: Thu, 6 Feb 1997 08:35:22 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: "Salvador Eduardo Tropea (SET)" <salvador AT natacha DOT inti DOT edu DOT ar>
cc: djgpp AT delorie DOT com
Subject: Re: DMA problems under Win 3.1
In-Reply-To: <m0vs6Fi-000S1pC@natacha.inti.edu.ar>
Message-ID: <Pine.SUN.3.91.970206083217.4379C-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On Wed, 5 Feb 1997, Salvador Eduardo Tropea (SET) wrote:

> Do you know if Windows uses all the 4 rings?, the only way that I imagine to 
> get this difference is if the DJGPP program runs in a different ring than the 
> real mode one. Do you know another case?

Yes.  If the DOS extender and/or DPMI host built into Windows 
deliberately disables DMA access, then it will affect protected-mode 
programs, but not real-mode ones, then you would see such effects.

And no, I don't know if Windows uses all the 4 rings, or whether 
real-mode programs run at different ring (I'd guess they run in the same 
ring, though).