[rescue] Sun Ultra 60> 2 Gb Memory ?

[Mark M]

Well, there is an additional gate array chip on the 256s(I believe every
variant), so it's possible that the U60 simply doesn't know how to work it.
I have a hunch the U30s are in the same boat.

As far as a way to hack the OBP to enable or add functionality to the
memory controller, I'd imagine it's possible, but that's way out of my
league. Though I wish I could meaningfully contribute.

-mark

On Sat, May 7, 2022 at 2:11 PM Chris Quayle <syseng at gfsys.co.uk> wrote:

>
> >
> > Today's Topics:
> >
> >     1. Re: Sun Ultra 60>  2 Gb Memory ? (Ethan Hawke)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Sat, 7 May 2022 13:11:02 +1000
> > From: Ethan Hawke<ehawk at ember.systems>
> > To: rescue at sunhelp.org
> > Subject: Re: [rescue] Sun Ultra 60>  2 Gb Memory ?
> > Message-ID:<1adcbcd9-6b24-fb4c-0834-a79f5ebc42be at ember.systems>
> > Content-Type: text/plain; charset="utf-8"; Format="flowed"
> >
> > The DSC (Memory Controller in the U2) can only address up to 2GB of
> > total memory, I would guess that 256MB SIMMs would be treated as 128MB
> > as the extra addressing pins would probably be grounded.
> >
> > Cheers,
> > Ethan
>
>
> >
> > On 5/7/22 04:22, Mark M wrote:
> >> There were 256MB Dimms of that type (200pin), but were only ever
> >> certified for U80 and E450s.
> >>
> >> The handbook memory compatibility matrix actually notes that they do
> >> work in e60s but there's an obp bank limit of .5G.
> >>
> >> All that said, I've never tried, but would, if my machines weren't in
> >> storage at the moment.
> >>
> >> -mark
> >>
>
> Thanks for the replies. If you think that 2Gb is a signed 32 bit number,
> the 2Gb limit would make sense, but if 256 works in a U80, I wonder if
> the obp firmware could be hacked to allow more than 0.5Gb per bank ?.
> Don't have a U80, but it follows on from the U60, perhaps just an
> upgrade ?. Ideal would be if the MB is the same ohysical size, but not
> exactly thick on the ground.
>
> May just buy 4 x 256 dimms to see what obp thinks it's looking at...
>
> Chris
>
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