It has four SIMM slots: two empty, two Sun items labeled 128Meg

I have two 64 Meg SIMMs from an iMac with the same shape and pin layout.
They will fit physically, but will they work?

--
Wes Groleau

He that is good for making excuses, is seldom good for anything else.
-- Benjamin Franklin

I think you will need to get Sun-specific SIMMS. They're not too
expensive on eBay.
Depending on the CPU speed, the Ultra 10 will run quite comfortably on
256MB.

I think you will need to get Sun-specific SIMMS. They're not too
expensive on eBay.
Depending on the CPU speed, the Ultra 10 will run quite comfortably on
256MB.

I think you will need to get Sun-specific SIMMS. They're not too
expensive on eBay.
Depending on the CPU speed, the Ultra 10 will run quite comfortably on
256MB.

Wes Groleau wrote:

> It has four SIMM slots: two empty, two Sun items labeled 128Meg
>
> I have two 64 Meg SIMMs from an iMac with the same shape and pin layout.
> They will fit physically, but will they work?

Possibly, but since I don't know what RAM an iMac uses I'm not sure -
but I have successfully used compatible PeeCee RAM in an Ultra 10. You
need 3.3V EDO DIMMs

First double-check physical compatibility by lining up a Sun DIMM and an
iMac DIMM edge-to-edge - you may find they are identical _except_ that
one of the two notches between pins is misaligned by about 1mm. This
slight physical incompatibility is easy to miss.

If you're certain of physical compatibility, obtain details of the iMac
DIMMs (numbers on any stickers, and numbers on the chips themselves),
and post and/or google them.

Sunny

Sunny wrote:
>
>
> Wes Groleau wrote:
>
>> It has four SIMM slots: two empty, two Sun items labeled 128Meg
>>
>> I have two 64 Meg SIMMs from an iMac with the same shape and pin layout.
>> They will fit physically, but will they work?
>
> Possibly, but since I don't know what RAM an iMac uses I'm not sure -
> but I have successfully used compatible PeeCee RAM in an Ultra 10. You
> need 3.3V EDO DIMMs

I _think_ that's what they are. These are 64Meggers.
I replaced them in the Mac with 128 Meggers that I bought
at Staples (where Macs cannot be found).

> First double-check physical compatibility by lining up a Sun DIMM and an
> iMac DIMM edge-to-edge - you may find they are identical _except_ that
> one of the two notches between pins is misaligned by about 1mm. This
> slight physical incompatibility is easy to miss.

No, every 'pin', notch, hole is identical. But I just noticed the
Sun DIMMs have nine chips each side while the others have eight on
one side. Does the Ultra require a parity bit?

> If you're certain of physical compatibility, obtain details of the iMac
> DIMMs (numbers on any stickers, and numbers on the chips themselves),
> and post and/or google them.

Sticker:
GMM2649233ETG
-7J 0122L
PC-100-322-620

Came from Crucial but doesn't say that on the DIMM.

--
Wes Groleau

"There ain't nothin' in this world that's worth being a snot over."
-- Larry Wall

Wes Groleau wrote:

> Sunny wrote:
>
>>
>>
>> Wes Groleau wrote:
>>
>>> It has four SIMM slots: two empty, two Sun items labeled 128Meg
>>>
>>> I have two 64 Meg SIMMs from an iMac with the same shape and pin layout.
>>> They will fit physically, but will they work?
>>
>>
>> Possibly, but since I don't know what RAM an iMac uses I'm not sure -
>> but I have successfully used compatible PeeCee RAM in an Ultra 10. You
>> need 3.3V EDO DIMMs
>
>
> I _think_ that's what they are. These are 64Meggers.
> I replaced them in the Mac with 128 Meggers that I bought
> at Staples (where Macs cannot be found).
>
>> First double-check physical compatibility by lining up a Sun DIMM and
>> an iMac DIMM edge-to-edge - you may find they are identical _except_
>> that one of the two notches between pins is misaligned by about 1mm.
>> This slight physical incompatibility is easy to miss.
>
>
> No, every 'pin', notch, hole is identical. But I just noticed the
> Sun DIMMs have nine chips each side while the others have eight on
> one side. Does the Ultra require a parity bit?
>
>> If you're certain of physical compatibility, obtain details of the
>> iMac DIMMs (numbers on any stickers, and numbers on the chips
>> themselves), and post and/or google them.
>
>
> Sticker:
> GMM2649233ETG
> -7J 0122L
> PC-100-322-620

Google says that's PC100 SDRAM, not EDO - in which case there _should_
be a discrepancy in notch location, but you say they are physically
identical. OTOH, there is no voltage discrepancy (both 3.3V), so it's
safe to try them once you have video and keyboard working.

Sunny

Sunny wrote:
>
>>> Possibly, but since I don't know what RAM an iMac uses I'm not sure -
>>> but I have successfully used compatible PeeCee RAM in an Ultra 10.
>>> You need 3.3V EDO DIMMs

And later

> Google says that's PC100 SDRAM, not EDO - in which case there _should_
> be a discrepancy in notch location, but you say they are physically
> identical. OTOH, there is no voltage discrepancy (both 3.3V), so it's
> safe to try them once you have video and keyboard working.

Are you sure? I thought EDO were the older smaller ones
with the spring steel catches on each end, where you put
the DIMM in at an angle and then straighten it to snap it
into the catches.

The Sun Ultra 10 has the larger ones where you put it in
straight and pull a plastic latch on each end into a notch
in the side of the DIMM.

But in any case, I'm not changing any hardware or software
before I see a prompt on a screen. Unless I have to do it
to see that prompt!


--
Wes Groleau
"Two things are infinite, the universe and human stupidity.
But I'm not so sure about the universe."
-- Albert Einstein

Wes Groleau wrote:

> Sunny wrote:
>
>>
>>>> Possibly, but since I don't know what RAM an iMac uses I'm not sure
>>>> - but I have successfully used compatible PeeCee RAM in an Ultra 10.
>>>> You need 3.3V EDO DIMMs
>
>
> And later
>
>> Google says that's PC100 SDRAM, not EDO - in which case there _should_
>> be a discrepancy in notch location, but you say they are physically
>> identical. OTOH, there is no voltage discrepancy (both 3.3V), so it's
>> safe to try them once you have video and keyboard working.
>
>
> Are you sure?

Sure that the Ultra 10 uses 3.3V EDO RAM? Yes - "The memory architecture
uses the 168-pin JEDEC standard extended data out (EDO) 3.3-VDC buffered
DIMMs". Quote from the Ultra 5/10 Service Manual, section C.1.4:

http://www.sun.com/products-n-soluti...05-0423-11.pdf

> I thought EDO were the older smaller ones
> with the spring steel catches on each end, where you put
> the DIMM in at an angle and then straighten it to snap it
> into the catches.

Yes, EDO RAM is available in several form factors, including the 72-pin
layout you describe and the 168-pin format used in the Ultra 5/10.

> The Sun Ultra 10 has the larger ones where you put it in
> straight and pull a plastic latch on each end into a notch
> in the side of the DIMM.

I'm familiar with them.

> But in any case, I'm not changing any hardware or software
> before I see a prompt on a screen. Unless I have to do it
> to see that prompt!

Good plan :-)

Sunny