Peculiar R5K Indy module... - Printable Version

+- IRIX Network Forums (//forums.irixnet.org)
+-- Forum: SGI/MIPS (//forums.irixnet.org/forum-3.html)
+--- Forum: Hardware/Triage/Repair (//forums.irixnet.org/forum-11.html)
+--- Thread: Peculiar R5K Indy module... (/thread-1917.html)

---

Peculiar R5K Indy module... - mapesdhs - 02-28-2020

Well here's an odd one, check this out:



Those familiar with Indy CPUs will immediately figure it's an SC R5K model, but note the 'R5-150PC' sticker and the oddly placed PN sticker aswell. it certainly has all the extra ICs & cache normally present on an SC version, but it shows up and behaves as a PC type, ie. no L2 at all. And the PN sticker does look like it's covering up a normal SC type PN.

This is the first time I think I've come across a CPU which has been used by SGI in this way, though whether or not it was a faulty part repurposed as a PC model (standard practice with x86 & GPUs, ie. binning) or instead is an SC they deliberately modified in order to satisfy a PC order (like the AV board socket cover for O2), who can say.

Anyone else encountered SGI parts which are marked and operate as something other than how they appear?

Ian.

---

RE: Peculiar R5K Indy module... - kaigan - 02-28-2020

That's really interesting! I can't say I've ever seen anything like that, myself. Perhaps this was a particularly late example of a request for a PC part and SGI was primarily manufacturing SCs. It could have just been easier to modify an SC to fill the order than to manufacture more PCs.

---

RE: Peculiar R5K Indy module... - opcode - 04-25-2020

Maybe it was supposed to be a unit with SC but it failed QA/testing or the cache ram was bad so they sold it as a PC unit?

---

RE: Peculiar R5K Indy module... - mapesdhs - 04-25-2020

Knowing SGI, it's more likely they had an order which required a PC type but didn't have one, so they shipped out a crippled SC. They did this with various parts, most famously the AV board for O2. It could be as you say, but that would be unusual for various reasons, inparticular given the cost difference of a PC vs. SC it would make far more sense to simply repair an SC unit that had a fault in the cache logic somewhere (it would require more time & effort to put the PC cripple in place; in 25 years this is the first time I've seen such a module).

Ian.

---