[SPARCbook] What is the Max Ram for 3GX....???

[Mike Ekholm]

but would they fit in the area given?  I dont think they would.  you would
need to do some case hacking to get it to work.

On Tue, Sep 04, 2001 at 05:08:49PM -0400, Thomas Roehr wrote:
> Just pick up a couple of those sim adapters that let you plug 2 or 4 sims into one
> slot. They have jumpers to configure the memory layout. No battery, but you can
> ahve 256 MB's of ram. They are only about $20 each.
> 
> Tom Roehr
> troehr at nj-onramp.com
> 
> Bob Krzaczek wrote:
> 
> > Thus spake Ken Hansen:
> > ; You can not *stuff* 256 Meg of RAM in a SPARCbook 3GX
> > ; without *severe* hardware hacking, of they type that
> > ; would *probably* render your laptop no longer
> > ; portable.
> >
> > Severe?  Sure.  Unportable?  "Nahhhhhhhh" :)
> >
> > Actually, just before I moved onto a different laptop, I was
> > considering exactly this project on my 3GX.  It really shouldn't be
> > *too* hard (of course, I say that with the confidence of someone who
> > no longer plans on doing the work).
> >
> > In the event that there's a hw hacker or two on this list, let me
> > encourage you!
> >
> > Consider: the microSparc-II cpu in the 3GX has a nice, friendly,
> > simple DRAM controller integrated right into it.  It should be fairly
> > straightforward, using Sun's own documentation on the CPU (available
> > as a PDF from their web site), to trace back the signals from the SIMM
> > socket and determine which memory control lines (the various RAS, CAS,
> > and high address lines) are where on the SIMMs.
> >
> > At that point alone, one could guess what was different about the
> > Tadpole 64M SIMMs.  Sure, we know they appear as two 32MB SIMMs to the
> > hardware; but, also bear in mind that a 32MB SIMM is really two 16 MB
> > SIMMs. So, expect a little weirdness here; at a guess, I'm betting on
> > seeing some weirdness with an extra RAS line from the CPU stealing an
> > unused line on the SIMM socket.  Either way, it shouldn't be too hard
> > to figure out exactly how the 3GX SIMM sockets were wired wrt. to the
> > DRAM controller.  From that, I one shold be able to infer how the
> > special 64M SIMMs were set up.
> >
> > At that point, things can go one of two ways.
> >
> > If you're lucky.  Super lucky.  More lucky than you have any right to
> > expect, you might discover that some existing 64MB SIMMs could be
> > modified to match Tadpole's design.  This would almost certainly
> > require one of the "chip heavy" 64MB SIMMs; that is, a SIMM with many less
> > dense chips, rather than a few dense chips.  Sadly, most 64MB SIMMs
> > are exactly this latter catgeory.
> >
> > So, the odds are a little against you there.
> >
> > The alternative, of course, is that you could add SIMMs inside your
> > 3GX.  There's clearance and space inside that could accomodate two
> > SIMMs, providing you're good with a soldering iron around delicate
> > circuitry (let me stress that you'll be wiring to signals that come
> > right off the CPU, so be @#$%^@ careful).  If you're industrious, you
> > might try your hand at low profile right handle SIMM sockets;
> > otherwise, you'll need to put some good thought into a mounting
> > strategy for the extra SIMMs.
> >
> > Now, before anyone wets themselves: THIS IS ALL THEORETICAL.  Don't
> > try this if you have any doubts of your own abilities, or are scared
> > of toasting your laptop.  There are lots of single mistakes you could
> > make when working on hardware like this that could utterly trash your
> > laptop.  So, DON'T DO IT unless you're prepared to take responsibility
> > for your actions.  I have nothing to do with this or what you do.
> >
> > (ahem) Sorry.  You see a lot of that on the 'net.  Anyway.
> >
> > Amusing aside: I *loved* my 3GX, and often wondered why someone else
> > hadn't done something like this before, once we realized how scarce
> > the 128MB kits for the 3GX are.  Eventually, my impatience at swapping
> > drove me to plan this project out, and I was ready for some
> > exploratory surgery (I'm familiar with the inside of a 3GX, having
> > opened it up in the past to fix a deteriorating keyboard (it turned
> > out to be a slipping connector) and other things over recent years).
> > Then, after I had read up on the CPU and learned something of common
> > 72pin SIMM design, I got a new laptop from work.
> >
> > And that's when I realized why no one else had done this before.
> >
> > So, IN THEORY, this is all pretty straightforward (sheesh, it's just
> > memory).  Chances are good that a couple people with the right skills
> > could hook up and pull this off.  At the least, you could have a 3GX
> > with four 32MB SIMMs; if you're insanely lucky, maybe more.  So, if
> > you're good, and have the inclination and the time, think about it.
> > It really can't be *that* hard.  And you'll be a hero.
> >
> > (Oh, great. Now I'm all nostaglic for "bat", my old 3GX... I think I
> > might dust it off and boot it up this afternoon... ;)
> >
> > Cheers,
> >
> > // bob
> >
> > --
> > // Bob Krzaczek, RIT Center for Imaging Science               <krz at cis.rit.edu>
> >
> > _______________________________________________
> > Sparcbook mailing list  -  Sparcbook at sunhelp.org
> > http://www.sunhelp.org/mailman/listinfo/sparcbook
> 
> _______________________________________________
> Sparcbook mailing list  -  Sparcbook at sunhelp.org
> http://www.sunhelp.org/mailman/listinfo/sparcbook

 -Mike Ekholm

-- 
UNIX Sys Admin | ekholm at ekholm.org | http://www.ekholm.org | IRC: Nalez
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    "It's hard to find people in society who can administer UNIX
     and professionally carry a weapon."
       - Jim Williams, former FBI Computer Intrusion Squad agent