Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!wugate!uunet!yale!eagle!flinton
From: flinton@eagle.wesleyan.edu
Newsgroups: comp.sys.att
Subject: Re: Achieving maximum expansion memory without 2MB Card,  How??
Message-ID: <3492@eagle.wesleyan.edu>
Date: 13 Nov 89 20:52:22 GMT
References: <553@alfred.UUCP>
Followup-To: unix-pc.general
Lines: 25

In article <553@alfred.UUCP>, elliot@alfred.UUCP (Elliot Dierksen) writes:
 
> I have a 3B1 (used to be a 7300 before I hacked it to bits!!) that currently
> has 3.5MB of RAM.  I have a 512K RAM card & a 1MB Combo card currently
> installed. My question is: If I fully populate the Combo card, am I going to
> be able to get to that 4MB point or is that 512K that I add just going to
> step on the 512K card.  I thought I had heard something about being able to
> path the cards so they would run correctly.
> 
> If it's not possible, please let me know.  I would hate to have a 512K
> paperweight and still only 3.5MB. Any assistance/comments is greatly
> appreciated..  Thanx,

In the First Edition (November 1986) of the "S/50 Reference Manual" -- aka
the UNIX(r) PC Reference Manual -- page 7 of Appendix C (Expansion Memory
Locations) clearly suggests that the _only_ way to achieve 4.0 Meg is
with 2.0 Meg on the CPU board and a fully populated 2.0 Meg RAM card in any
slot.

If someone knows a hardware mod with which to overcome this -- or better still
a hardware mod to utilize all 24 RAM address lines (instead of the 22 actually
used -- see above-mentioned Ref. Man. Chapter 2 pages 2-2 and 2-3) -- there'll
surely be wide interest in seeing such info posted.

-- fejlinton