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From: psfales@ihlpe.ATT.COM (Peter Fales)
Newsgroups: comp.os.minix
Subject: Re: EMS spec
Message-ID: <1717@ihlpe.ATT.COM>
Date: Sat, 25-Apr-87 23:02:18 EDT
Article-I.D.: ihlpe.1717
Posted: Sat Apr 25 23:02:18 1987
Date-Received: Sun, 26-Apr-87 22:34:14 EDT
References: <497@gouldsd.UUCP> <266@inuxf.UUCP>
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 29
Summary: Careful what you mean by EMS Spec!

In article <266@inuxf.UUCP>, matt@inuxf.UUCP (Matt Verner) writes:
> > 
> > 	I want to look into writing an EMS driver into the RAMdisk driver.
> > Can anyone out there give me pointers to how the EMS hardware is accessed
> > by software ? I have a feeeling it's a dreadful kluge, but it might be nice
> > to be able to free up more RAM by stuffing the RAMdisk into kluge-mem.
> > 
> 
> Get a copy of Advanced MSDOS by Ray Duncan (Microsoft Press).  It has a VERY
> complete description of the EMS standard.  We used it to write our propreitary
> EMS stuff.

There is something that people may be missing when they talk about writing
an EMS driver for MINIX.  The EMS spec describes how an application talks
to EMS memory using the driver provided by the manufacturer of the EMS
board.  There is no requirement that the actual hardware implementation
be the same from manufacturer to manufacturer, only that the view
provided to the application remain consistent.  In fact, I have a copy
of a program that purports to simulate EMS memory using a disk file.  You
can certainly believe that that EMS "board" wouldn't be compatible with
a hardware implementation.

While Ray Duncan's book is top notch (I have a copy myself) it would
provide zero help in writing a driver for MINIX.
-- 
Peter Fales		UUCP:	...ihnp4!ihlpe!psfales
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