Date: Mon, 24 Jun 1996 18:23:32 -0700 (PDT)
From: Samuel Vincent <svincent AT cs DOT sonoma DOT edu>
To: djgpp AT delorie DOT com
Subject: Re: Four Trivial Questions and
In-Reply-To: <199606240520.AA143923651@relay1.geis.com>
Message-ID: <Pine.GSO.3.94.960624181959.24760B-100000@zippy>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Mon, 24 Jun 1996 j DOT aldrich6 AT genie DOT com wrote:

> Reply to message 5586869    from ROCKSOLID AT WAVE DOT NET on 06/23/96  7:08PM
[snip]
> >What exactly is DPMI?
> 
> DPMI = DOS Protected Mode Interface, a method of breaching the 16-bit
> boundary that has confounded programmers for ages.  Under DPMI, the
Not necessarily ;)

> processor runs in true 32-bit mode, and all memory (physical and virtual) is
> combined into one large pool of memory that is limited only by the size of
Not necessarily...

> your machine.  You don't have to worry about segments, 64K blocks, or
> fitting your program into the lower 640K of RAM.  The DPMI host takes care
> of all of that for you.
Not necessarily

> Plain, vanilla DOS doesn't allow you to use DPMI.  You have to use a
It just doesn't come with a dpmi provider..

> program which provides DPMI services before your 32-bit pmode programs
> can run.  The readme.1st file contains a complete list of the programs which
> provide DPMI; the most common are QDPMI, 386MAX, and Windows.  DJGPP
> comes with a free DPMI host called CWSDPMI that is automatically loaded
> by your programs if no other host is available.

DPMI is just Dos Protected Mode Interface...
It gets you into Protected mode.  Now there is 3 bit protected mode and
there is 16 bit protected mode.  Not all servers provide 16 bit support.
Not all servers provide 32 bit support (Though most today should.)

It is just a method to allow programs access to a protected mode
environment from within a protected mode environment where it couldn't get
there itself.

-Sam