Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!mcsun!ukc!acorn!moncam!emmo
From: emmo@moncam.co.uk (Dave Emmerson)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Extended vs Expanded
Summary: minor comments
Keywords: Everex 3000 Extended Expanded RAM
Message-ID: <364@marvin.moncam.co.uk>
Date: 15 Jan 90 17:11:42 GMT
References: <6258@ubc-cs.UUCP>
Organization: Monotype ADG, Cambridge, UK
Lines: 30

In article <6258@ubc-cs.UUCP>, jalbert@cs.ubc.ca (Francois Jalbert) writes:
> [bulk of summary deleted]
> to the slower bus. I was very surprised to see that four 256Kb chips are 
> slightly cheaper than one 1Mb chip. >

This is current policy of Japanese (& therefore world) DRAM manufacturers,
in order to push sales of the 4Mbit DRAM, and reduce the glut (?) of
1Mb devices, 1 x 4Mbit costs 5 x 1Mbit ; 1 x 1Mbit costs 5 x 256K .....
I'd expect to see PC add-ons using 4Mbit devices in a year or so. 
Now the market is more stable, memory prices should follow the 30% / year
reduction curve, so if you're still waiting 'till you can afford them
don't hold your breath : unless a non-Japanese mfr turns these out in
very high volume at low prices, they'll get their own way.

> [more deleted]
> Either the scan is not performed correctly, or some upper memory areas 
> are not compatible with the 64Kb cache at hand on some AT clone. Impose 
> upon the driver that it use the segment D000H for its cache. Once I did 
> that, the sporadic data corruptions I had experienced in the RAM disk 
> disappeared. 

Doubtless this holds good on Francois' setup, and is well worth the mention,
but don't automatically assume that it will be necssary (or even work) 
on *yours*. Try it 'as is' first, then experiment with other segments
if necessary. You cannot locate it anywhere where you already have a
BIOS ROM and expect either to work.

Sorry for nit-picking, it was a good, constructive article.

Dave E.