Supported PowerMac 6100 L2 sizes?

[ymk]

Can you please take a picture of the cache-simm...I am very interested in these.
I am searching for years to get such a thing.

 

[Bolle]

Ha, looks like this has logic for tag comparision on it using standard SRAM and those two PLDs. If we can get that thing my way somehow I should be able to replicate it.

 

[MrFahrenheit]

Ha, looks like this has logic for tag comparision on it using standard SRAM and those two PLDs. If we can get that thing my way somehow I should be able to replicate it.

I wonder what maximum size you could make. If anyone can do it, it’s Bolle!

 

[Nathan_A]

I wonder what maximum size you could make. If anyone can do it, it’s Bolle!

I've wondered the same thing about the Old World PCI machine's L2 cache modules. I have a few working 1MB modules and a few defunct ones that cause a machine not to chime or boot when installed. I'd donate them to any attempt to see if 2MB or 4MB can work. However, in the case of both the early Nubus Power Macs and the early PCI ones, I wouldn't be surprised if 1MB is the addressable maximum by their respective memory controllers.

 

[just.in.time]

@Bolle that would be awesome if you were able to build some. I’d definitely buy one.

 

[Fizzbinn]

@Bolle that would be awesome if you were able to build some. I’d definitely buy one.

As would I!

 

[JustG]

I'd be in for four.

 

[Juror22]

that would be awesome if you were able to build some. I’d definitely buy one.

...and me!

 

[Nathan_A]

...and me!

I'd buy two. One for my 7100 and one for my 8100.

 

[jajan547]

There’s some Sonnet PVT boards for the G3 accelerator on eBay they have absolutely no chips but I assume you can put 1MB on that and have it work?

 

[Melkhior]

According to some old MacTech article, there's no theoretical limit on the L2 cache size for the NuBus PowerMacs. Which seems plausible, if the cache embarks all the required memory and logic (tag, comparison logic, ...) to answer the CPU request (later systems would rely on the tag and comparison logic being part of the system controller and so limited in size to whatever those can handle; of course even later the L2 would migrate to the CPU itself).

Edit; from the readable chips in @ymk picture...

MCM6206 are SRAMs (32kx8)
74FCT521 ares 8-Bit Identity Comparator
74FC244 are buffers/line drivers
PI5C3257W is a Multiplexer/demultiplexer Bus Switch
And a couple of PALs
So I suppose the first part of the picture is the controller part and contains everything but the actual cache SRAMs

TC558128AJ are 128kx8 SRAMs, so the second part of the picture contains the actual 1MiB of cache SRAMs

Would be interesting to figure out the details of the wiring and PALs content. In addition to duplicate that 1 MiB module, it could theoretically be possible to design an even larger one by having more data SRAM, more tag SRAM, and larger comparators (though it would probably be prohibitively costly vs. the expected performance gain).

 

[Nathan_A]

That's really interesting. I'd love to put a 4MB L2 cache in my Nubus Power Macintoshes.

Are there similar MacTech articles about the Catalyst & Tsunami architecture machines?

 

[dr.zeissler]

Anything new to this toppic? still searching for the 1MB 2nd-Level caches for my three PM 6100/66

 

[AF_APPLETALK]

I have a Performa 6116CD I'm restoring right now. Once I get it back on its feet, I'll get a prepaid card and try ordering the L2 cache from that micromacs site and let you all know what happens.

 

[cheesestraws]

I have a Performa 6116CD I'm restoring right now. Once I get it back on its feet, I'll get a prepaid card and try ordering the L2 cache from that micromacs site and let you all know what happens.

(Parenthetically, I like your username)

 

[KennyPowers]

I'd buy a cloned 1MB cache for my 6100.

 

[AF_APPLETALK]

(Parenthetically, I like your username)

Ty Mr Cheesestraws!

 

[zefrenchtoon]

Any news @Bolle ?

 

[eraser]

I have a Performa 6116CD I'm restoring right now. Once I get it back on its feet, I'll get a prepaid card and try ordering the L2 cache from that micromacs site and let you all know what happens.

MicroMac is long out of business. The site is still up but the business is gone. It's cool having the site still around but it's sad because it teases us with all the upgrades that are no longer for sale.

 

[dust bunny]

I would buy a cloned 1mb L2 cache stick, I've been looking (mostly on ebay) for around 10 years.
I would be fascinated to see if 2mb and 4mb work, I would be interested in buying if I can afford it