re: Is Cray shipping (as far as current systems) anything other than Opteron based systems?
They still have vector based X1E: cray.com
BTW, the filing problem the NASDAQ made an issue about has been solved: "The Nasdaq Stock Market stating that the filing delinquency, for which Cray had requested a hearing, has been cured and the hearing has been cancelled as moot. "
I also think that socket 939/940 FPGA's will be a problem for XD1 sales (as it commoditizes FPGA solutions, like is also happening to some extent HTX-based connectivity, it'll become less easy for Cray to differentiate their solution). In some aspects the market is moving quite a bit faster than Cray can (their design cycles are based on main frames while everyone else's cycles are based on mid range systems). Cray is reasonably save in high end, but a bit vulnarable in mid range and that situation is not going to change soon. Still winning DARPA funding is quite an event for Cray.
re: XT3 currently uses some custom IBM connectivity parts (which I seem to recall were a source of some problems earlier). I wonder if Cray is going to dump these for pure HT based connectivity, potentially with some custom logic like Horus.
Good question. Theoretically there are three possibilities:
1) More HT links per processor. As you pointed out previously the HT3.0 presentation suggests 'more interconnect links', see slide 7, here: hypertransport.org One of the questions is how much more. You need a minimum of 7 HT links for a 3d mesh (actually 6 for the mesh + 1 for the IO). That's 4 more than current situation. Sure that would make life easier for them as they don't have to pay IBM to upgrade the custom communication chip, but it's rather hard to predict that 2008 Opteron will really have 7 links.
2) Upgrade IBM communciations chip (this one already has 6 comm-to-comm chip links + 1 HT link). I don't know. The IBM communciation chip works and it might not require that much more money to upgrade it.
3) HT switch somewhat like you said, but I think it'll need to have way more HT ports that you mentioned.
BTW, name of that DEC/Alpha data communications team wasn't API, was it?
Regards,
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