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Having been at Sun and having been (too) intimately involved with the microprocessor side of the house for way too damn long, I can tell you that when it came t
by bcantrill 13y ago
Having been at Sun and having been (too) intimately involved with the microprocessor side of the house for way too damn long, I can tell you that when it came to microprocessors, Sun was all vision and no execution. The theme that was repeated over several microprocessors: a new, big idea that made all of the DEs horny, but that proved annoyingly tricky to implement. Sacrifices would then be made elsewhere in order to make a tape out date and/or power or die budget. But these sacrifices would be made without a real understanding of the consequences -- and the chip would arrive severely compromised. (Or wouldn't arrive at all.) Examples abound but include Viking, Cheetah, UltraJava/NanoJava/PicoJava, MAJC, Millennium (cancelled), Niagara (shared FPU!) and ROC (originally "Regatta-on-a-chip", but became "Rock" only when it was clear that it was going to be so late that it wasn't going to be meaningfully competing with IBM's Regatta after all). The only microprocessor that Sun really got unequivocally right (on time, on budget, leading performance, basically worked) was Spitfire -- but even then, on the subsequent shrinks (Blackbird and beyond) the grievous e-cache design flaws basically killed it.
Point is: in microprocessors, execution isn't everything -- it's the only thing.
- StillBored 13y agoROC (originally "Regatta-on-a-chip") Really? Ha, that is funny! I guess sun got the codenames and the fact that it was MCM full of GP's, but apparently didn't notice why it was MCM, or the fact that there were 4 MCM's in the full regatta config. I mean, like, did sun expect to make a wafer level chip? Its good to know the envy went both directions, I remember a lot of talk about sun's E10k...
- gonzo 13y agoHi Brian. Spitfire was only on-time compared to the debacle of Viking and Voyager. Thanks for dredging up the nightmare. :-)
- bcantrill 13y agoMan, Voyager -- forgot that one! And "debacle" is really the only word for Viking. A major rite of passage in kernel development in the 1990s was finding your first Viking bug; I found mine within a month of joining in 1996 (a logic bug whereby psr.pil was not honored for the three "settling" nops following wrpsr, allowing a low priority interrupt to tunnel in -- affecting all sun4m/sun4d CPUs). Bonwick's was still the king of the hill, though: he was the one who discovered that the i-cache wasn't grounded out properly, causing instructions with enough zeros in them to flip a bit (!!). The story of tracking that one down (branches would go to the wrong place) was our equivalent of the Norse sagas, an oral tradition handed down from engineer to engineer over the generations. Good times!