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From: navas@cory.Berkeley.EDU (David C. Navas)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Memory for A3000...
Message-ID: <28898@pasteur.Berkeley.EDU>
Date: 17 Oct 90 19:03:13 GMT
References: <1990Oct17.015046.10982@ncsuvx.ncsu.edu>
Sender: news@pasteur.Berkeley.EDU
Reply-To: navas@cory.Berkeley.EDU
Lines: 34

In article <1990Oct17.015046.10982@ncsuvx.ncsu.edu> harris@hobbes.catt.ncsu.edu (Michael Harris) writes:
>Well, I finally did it.  I saved up my money, picked up the phone and ordered
>2 megabyes of 80ns 1MegX4 static column zips.  An hour later the company I
> "No, we were told that in order for
>the 3000 to realize that you have installed memory, you must completely fill
>a bank."

Now isn't that typical, blame the computer... ;)
Yes, you must install a full bank, and the reason is simple.  Each 1Mx4 outputs
four bits of information.  The A3000 has a 32 bit architecture, therefore
you need eight (8x4 = 32) chips to fill a 32 bit, long-word request.  I
suppose it would be possible to support half-banks, but then each long-word
request would require two read-cycles.  In other words, there would be a
staggering slow-down in your, supposedly, FASTer memory.  And then there
would be the question of the supporting logic....

If you can only afford 2megs, either buy 16 256x4's, or wait until you can
afford 8 1Mx4's.  You *could* buy a 16-bit memory board, though why the
dickens you'd want to would be beyond me.

[I'm a software guy who likes to dabble in hardware, I await correction :)]


>
>Thanks,
>--
>Michael Harris - harris@hobbes.catt.ncsu.edu     __      ___ ___
>       North Carolina State University          |     /\   | |   Computer and
>"If there isn't time to do it right the first   |    /  \  | |   Technologies
>time, then how can there be time to do it over?"|__ / /__\ | |   Theme Program


David Navas                                   navas@sim.berkeley.edu
"Excuse my ignorance, but I've been run over by my train of thought."  -me