[Python-Dev] One more dict trick

[Tim Peters]

[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