SGI: Hardware

I found a matching set of 8: 32x36bit, FPM, 128MB 72pin SIMMs @ 60ns.

I was planning on giving my Indigo2 a nice 1GB RAM upgrade from its lowly 256MB.

Upon swapping all the RAM and powering on, I just get the orange power light; no beeps, no video display, nothing.

Is there a flashrom/firmware upgrade necessary to support 1GB?

Anyone have experience running 1GB RAM in an R10K Indigo2?

Any help is much appreciated.

There was a fair amount of discussion about this at the time. My memory ain't so great but it seems to me that in general, the I2 is stuck at or near 768 megs of memory. Under certain circumstances (which I totally forget) you could get it to go higher.

This could all be some fantasy floating around in my drug-addled brain, though.

I set mine up with 4, 128 MB simms and 8, 64 MB ones. It worked without any issues.
PROM Monitor SGI Version 6.2 Rev A Aug 26,1996

One thing to consider is that larger DRAMs, ceteris paribus, use more power and the power budget is limited.
SIMMs using 3V DRAMs and level converters seem to be safer.

Oh also if you only use 8 SIMMS you need to put them in the right places. The lowest-numbered group of slots needs to have memory in it or the machine can't boot. I think in the Indigo2 that's the group farthest from the CPU.

This was my motivation to try it: http://www.futuretech.blinkenlights.nl/i2gigaram.html

My machine currently had 8 x 32mb SIMMs, and they were installed in the slots closest to the front of the computer and then working back so the last 4 slots near the rear of the machine were left unpopulated.

I simply removed those 8 and repopulated with my new 128MB SIMMs in the same locations. No go.

I even tried removing 4 and just leaving the first 4 slots populated but that doesnt work either.

Is there a way to upgrade the PROM to support more memory? I wonder if a specific revision of chip has to be present?

My PROM says: Version 6.2 Rev A, IP28 Aug 26, 1996 - 64 Bit

I also checked and my DIMMs say "5V". They are labelled FPM, so I would assume these chips would work but it doesnt seem to like any combination of these SIMMs in any slots whatsoever.

I even tried mixing 4 of the 128MB with 8 of the 32MB and 4 of the 32MB in different combinations and no go. Maybe I just happend to find incompatible ones...

OK, we have the same PROM version. At this point I don't know if it's an issue with the SIMMs, or if the IP28 board is a revision that just doesn't work with them (could be possible, as only 64MB SIMMs-768MB was officially supported).

Sometime I can take out the SIMMs I have and tell you the numbers on them if that would help.

I've got a "gigaram' Indigo2 R10K myself. Standard issue IP28 board and never looked at the PROM either.

I'd suspect the RAM. The ones I (and most others, probably) used, are HP parts and they have tin contacts rather than gold. This makes them more susceptible to oxidation and I think the combination of tin contact SIMMs and gold contact sockets may lead to other problems. Ive had to clean the contacts with alcohol a couple of times over the years, unlike most of my other SGIs.

Also I'm pretty sure the slots at the back of the case are Bank A, versus B and C. Check TechPubs but I'd start with the lowest ordinal bank and work up from there. I've got 1GB in an R10k I2, using the HP D NNNN parts mentioned on the NekoWiki I2 page...

Ian's page is the reference I used, so not sure what I can add to that.

According to the Indigo2 User Manual (see attachment) Bank C is closest to the FRONT of the computer.

I suspect I just got a set of memory that isnt supported. These were Tin contacts and didn't show any signs of oxidation. Just my luck, I pick a set that are not compatible...

I've contacted the seller to arrange to send them back.

I will try to locate the same parts as described in the Wiki and see if that works better.

Thanks to everyone for chiming in!

Hmm - thanks for posting that snippet, apparently I've been filling the SIMM slots backwards...

Errors in the users' manuals aren't unknown. From a cooling standpoint it was widely recommended on comp.sys.sgi and elsewhere to use the slots farthest from the CPU first, because the processor module interferes with airflow over the RAM.

I have my 128MB SIMMs in Bank A, and the 64MB ones in B and C. The Bank A SIMMS are labeled both "IBM FRU 76H4896 OPT 94G6682" and "Samsung KMM53632000BK-6".

Somewhat of a side note, but the dissimilar metal corrosion problem with tin-lead SIMMs in gold sockets or vice versa should be preventable by using a Polyphenyl-ether based contact rejuvenator.