*BSD News Article 5852


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From: donegan@stanton.UUCP (Steven P. Donegan)
Newsgroups: comp.unix.bsd
Subject: Re: 386BSD Questions
Summary: Memory Limits
Message-ID: <65158@stanton.UUCP>
Date: 27 Sep 92 14:33:34 GMT
References: <2013.416.uupcb@pcb.batpad.lgb.ca.us> <53950@dime.cs.umass.edu>
Organization: Stanton Public Domain Systems, Stanton, Ca.
Lines: 38

In article <53950@dime.cs.umass.edu>, shri@unreal.cs.umass.edu (H.Shrikumar) writes:
> In article <2013.416.uupcb@pcb.batpad.lgb.ca.us> mike.batchelor@pcb.batpad.lgb.ca.us (Mike Batchelor) writes:
> >
> >   this even an issue for 386BSD?  How about the Mylex and AMI
> >   brands?  Generic Taiwanese OPTI/AMI?  I read elsewhere in this
> >   group a reference to a 16Mb limit, but couldn't find any other
> >   details.  16M is a good amount to start with, but I would surely
> >   want to go to 32 or 64 later.
> 
>    If this 16 MB limit is dues to 24 bits of address on the ISA, then
> does it hold for memories (SIMMs) directly on the mother board ?
> On the Generic Taiwan OPTi/AMI boards ?
> 
> -- shrikumar ( shri@legato.cs.umass.edu, shri@iucaa.ernet.in )

There may be a 24 bit limit on the ISA (I don't have a hardware manual at
the moment) but why on earth would you be loony enough to want to put
memory on the ISA or EISA for that matter. There be wait states between
thee and the bus...


As to a limit of 16 meg of RAM that's rubbish unless you have a poorly 
designed motherboard (and in these days of 600$ US 486 motherboards you
should be able to replace a faulty design). My made in the USA 486/33 clone
handles 16 meg (actually 20 as there are 4 1 meg simms there as well as
the 4 meg simms) quite nicely. So there is no inherent design flaw which
precludes 32 meg usage at least in my board. For going the next leap to 64
meg - well I haven't done it myself and don't know offhand of any boards
with enough simm sockets at 4megX9 to accomodate 64 meg so you're on your
own :-)

By the way - what do you need 64 meg for anyway... Some major simulation?
Or far too many users for the CPU horsepower of a 486 :-)
-- 
Steven P. Donegan                     The opinions expressed here are mine
Senior Telecommunications Engineer    donegan@stanton.cts.com, stanton!donegan 
Information Services                  714-932-6055 voicemail
Western Digital Corporation           714-894-2246 uucp - nuucp no word