Nekochan Net

Which brings me to a proposal .... far be it from me to discourage jousting with windmills but any of this disassembly / reverse-engineering, re-imagining of the low level hardware design of Irix will at some point involve dealing with the PROM. And we have a project that already brought us the 600 mhz O2. It stalled at upgrading the PROM to deal with the 900 mhz pin-compatible processor. Maybe there is an even faster one now ....

If you guys who are excited about creating a HAL started your research in the O2 PROM area, you could bring the 900 mhz O2 to life as a first step. A 900 mhz O2 would be very very cool. I'd buy one in a heartbeat.

Sound interesting ?

Yes, it does. I looked into the O2 prom a while back and it didn't seem that completely insane to modify or replace. The most important bit would be to figure out how to use the PROM's apparent fallback to re-flash if I bad image were used. It looks like there's support in there, but I didn't reverse engineer it. IIRC, there's still a good risk of bricking the machine, though, as I think the entire PROM is flashed each time its upgraded. There's no write-protected early bootstrap code from what I could tell.

I messaged the original poster who did the first 600MHz chips to see if he had a 900MHz one I could play with (I think one or more were made, but it was abandoned when he discovered the O2 just wouldn't boot with the newer chip), but never heard back.

However, even if the PROM could be modified to work, I seem to recall that IRIX would need similar modifications as well. That's another layer of pain, but not one I care about too much since I've always tried to run NetBSD on my SGIs

This isn't that hard. I got IP12 and IP20 going pretty well in gxemul. Enough to boot irix 5.3 on IP12, as I recall. It seems like IRIX does pretty well on headless machines, so one doesn't always need any graphics emulation. Of course, I imagine most nekochaners would want a full Xsgi and desktop.

The newer high performance MIPS processors like the Octeon-II have no longer a SysAD bus. The fastest available MIPS processor with SysAD bus that can be used
on a sgi O2 CPU module is to my knowledge the RM7965A with 1 GHz. See here:
http://pmcs.com/products/details/rm7965a

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600 MHz, 2 GB RAM, 72 GB 15k RPM HD
180 MHz

Oh damn only a 1 ghz O2 ...

Seriously, edefault was the last one doing chip replacements on the O2 cpu pimm. If anyone is interested in furthering that project, he'd be the one to contact.

I'll put my order in now for a 1 ghz pimm, thank you very much !

Do you think the rest of the O2 could be able to benefit from a much faster processor?
There are other bottlenecks on the O2 (*cough* SCSI-I HD).
So a 1GHz MIPS O2 should be a good option.

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Sitting in a room.....thinkin' shit up.

400MHz R12k - Apple G4 Cube dual 500MHz/GF6200 - Newton Messagepad 2100 - Apple PowerBook 2400c/G3@240 - DECstation5000/133 - Apple Workgroup Server 9150/120 - Apple Macintosh IIfx - Apple Macintosh Color Classic (Mystic upgrade) - Sun Cobalt Cube 3 - Tadpole RDI UltraBook IIi

as far as I know, it is SCSI-3 level conformant (SPI) but limited to 40 MB/s (FAST-20) speeds.

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My dream project would be to produce new Octane mainboards but with fast memory and fast scsi and dual 800 or better cpu's. Basically an O350 in an Octane case ... That'd be a nice Irix desktop.

There are probably more practical dream projects out there, tho

There was a leak of IRIX 6.5.5 sourcecode a few years ago, if you could get hold if this it may be possible (with some considerable effort) to port the kernel to run on newer MIPS compatible hardware, with the kernel ported most userland programs should be able to run without modifications.

Ofcourse there is a legality question regarding leaked sourcecode, wether SGI would care or not is another matter... In an ideal world, SGI could open source IRIX now that they no longer have any commercial use for it.

SGI may not care, but then there are those nice people at whatever SCO is calling themselves nowadays, or any one of the other myriad licensors of SGI who still do have an interest, or then again SGI might not really "care" but might want to maintain their IP, or just get some easy money, or ...

And at the end of the day you'd still have to deal with the firmware problem.

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Damn the torpedoes, full speed ahead!

Systems available for remote access on request.

(single-CM)

"How much effort would it take to run the Irix kernel headless on a modern big-endian MIPS64 computer (like the Octeon-based computers)?"

Why? What would you be able to do on an Octeon that you can't do on a SGI?

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Experience the joy of running on a processor without hardware FPU, and as such seeing the performance of every floating-point intensive application drop to fractions of what it would be on an SGI, of course!

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R4000 R4400 R4400 R8000 R10000 R4000PC R4000SC R5000SC R5000 RM7000 2xR10000 R12000 - 2x2xR10000 R16000
among more than 150 machines : Apollo, Be, Data General, Digital, HP, IBM, MIPS before SGI, Motorola, NeXT, SGI, Solbourne, Sun...