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From: barrett2@ohstpy.mps.ohio-state.edu
Newsgroups: comp.sys.mac
Subject: Re: upgrading memory
Message-ID: <473@ohstpy.mps.ohio-state.edu>
Date: 12 May 89 09:11:08 GMT
References: <790001@hpnmdla.HP.COM> <111900060@uxa.cso.uiuc.edu> <3175@tank.uchicago.edu> <8378@phoenix.Princeton.EDU>
Lines: 44

> ...
> slightly more prosaic wording), fork over ~$300, pop open my Mac SE, swap
> two of the existing chips with the two new 1M (each, right?) things, and
> seal the whole tamale up again, and I'll have a 2.5M Macintosh on my hands?

Close.

First, a SIMM in not a ckip, but a small card with 8 chips (MAC) or 9 (IBM)

Second, 'opening your Mac will void your warranty'.  This does not really 
bother me, since most of us are no longer under warranty.  However, opening 
a Mac (I've cracked mine twice) is not a job to be taken lightly.

Third, the SIMM sockets are in pairs, so that you must be sure to use the 
correct sockets.

Fourth, you must remove a resistor (I believe I heard they had changed it 
to a jumper in later models, but I'm unsure of this point).  I believe the 
necessary information can be found in Tech Note 176 (comp.binaries.mac or 
sumex-aim in the tech directory).

> Does anyone know of any better offers on memory chips?
> 
> Should I buy now, or hope that the prices will drop further?

Since I don't receive MacWeek, I'd like a phone number for Technology Works 
(since no one seems to have posted it yet).

> And what, precisely, are DRAM chips, and are they a feasible (and cheap!)
> option?

Dynamic Random Access Memory.  As opposed to Read Only Memory (ROM, which 
can be programmed once be our beloved Apple) and Static RAM.  Dynamic RAM 
chips require the circuit to "refresh" the contents periodically (kind of 
like reviewing material for a test) while static do not.  This diffenence 
should not bother you.

> Any explanations to clear this up would be greatly appreciated!
> 
>      << Brian >>

I hope this helps.
- Tom Barrett (Ohio State University)
any errors are my own ignorance