Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!decwrl!amdcad!pepsi!phil
From: phil@pepsi.amd.com (Phil Ngai)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why can't 386MAX reclaim all 384K shadow RAM  on a C&T 386
Summary: C&T blew it, NEAT isn't
Message-ID: <29429@amdcad.AMD.COM>
Date: 8 Mar 90 21:46:02 GMT
References: <1990Mar8.004459.19945@cs.dal.ca>
Sender: news@amdcad.AMD.COM
Reply-To: phil@pepsi.AMD.COM (Phil Ngai)
Organization: Advanced Micro Devices, Inc. Sunnyvale CA
Lines: 28

In article <1990Mar8.004459.19945@cs.dal.ca> lane@cs.dal.ca (John Wright/Dr. Pat Lane) writes:
|My question is what do they do with the other 288K!  And if they do
|something important with it, what do they do if there is less than
|1Meg in the machine and the memory isn't physically there.

I'm not going to take the trouble to add up all 288K of your bytes for
you but you can get started by realizing that shadow RAM, while it can
be used, can not be relocated. If there is a resource at a shadow RAM
address which can not use shadow RAM, then that S.R. can not be used at
all. For example, if you have VGA, then all of the A000-BFFF (128
Kbytes) is used for the video display memory and all of that S.R. is
totally useless.

In summary, C&T's decision to force you to use shadow RAM was not
in your best interest.

|The Qualitas person opined that the Chipset/BIOS needed it for its own
|nefarious purposes but that led to my question as to what that might be
|and what happened if you had a 512K or 640K machine without any extra RAM.

This is a complete airhead type of answer. I expected better from
Qualitas.

I would certainly recommend Qualitas 386Max over QD QEMM-386.

--
Phil Ngai, phil@amd.com		{uunet,decwrl,ucbvax}!amdcad!phil
A PC without DESQview is like Unix without ^Z.