[Eric S. Raymond]
... So maybe there's a market for 128-bit floats after all.
I think very small. There's a much larger market for 128-bit float *registers*, though -- in the "treat it as 2 64-bit, or 4 32-bit, floats, and operate on them in parallel" sense. That's the baby vector register view, and is already happening.
I'm still skeptical about how likely those applications are to influence the architecture of general-purpose processors. I saw a study once that said heavy-duty scientific floating point only accounts for about 2% of the computing market -- and I think it's significant that MMX instructions and so forth entered the Intel line to support *games*, not Navier-Stokes calculations.
Heh. I used to wonder about that, but not any more: games may have no more than entertainment (sometimes disguised as education <wink>) in mind, but what do the latest & greatest games do? Strive to simulate physical reality (sometimes with altered physical laws), just as closely as possible. Whether it's ray-tracing, effective motion-compression, or N-body simulations, games are easily as demanding as what computational chemists do. A difference is that general-purpose *compilers* aren't being taught how to use these "new" architectural gimmicks. All that new hardware sits unused unless you've got an app dipping into assembler, or into a hand-coded utility library written in assembler. The *general* market for pure floating-point can barely support what's left of the supercomputer industry anymore (btw, Cray never became a billion-dollar company even in its heyday, and what's left of them gets passed around for peanuts now).
That 2% will have to get a lot bigger before I can see Intel doubling its word size again. It's not just the processor design; the word size has huge implications for buses, memory controllers, and the whole system architecture.
Intel is just now getting its foot wet with with 64-bit boxes. That was old news to me 20 years ago. All I hope to see 20 years from now is that somewhere along the way I got smart enough to drop computers and get a real life <wink>. by-then-the-whole-system-will-exist-in-the-superposition-of-a- single-plutonium-atom's-states-anyway-ly y'rs - tim