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

Tue Sep 4 17:06:57 CDT 2001

Yes they would, you just lose the battery space.

Tom Roehr
troehr at nj-onramp.com

Mike Ekholm wrote:

> 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>
> > >
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>
>  -Mike Ekholm
>
> --
> UNIX Sys Admin | ekholm at ekholm.org | http://www.ekholm.org | IRC: Nalez
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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