IBM never had a "huge investment" in VLIW. It was a research project, at
best. OTOH, Intel has a *huge* investment in VLIW, and it's a bus
that isn't going anywhere. It's too easy for us hardware folks to toss of
the hard problems to the compiler folk. History shows that this isn't a
good plan. Even if Intel *could* have pulled it off, where was the
incentive for the customers? They have a business to run and
processor technology isn't generally part of it.
You mean the work required to tune? People will optimize the hell out
of compute intensive code--to a point. The work required to get the
world-beating SpecFP numbers is probably beyond that point.
That was one, perhaps a big one. Intel's real problem, as I see it, is
that they didn't understand their customers. I've told the FS stories
here before. FS was doomed because the customers had no use for it and
they spoke *loudly*. Itanic is no different, except that Intel didn't
listen to their customers. They had a different agenda than their
customers; not a good position to be in.
If alpha and pa-risc hadn't been killed off, I might agree with you
about Itanium. No one is going to abandon the high-end to an IBM
monopoly. Never happen (again).
I gather that Future Systems eventually became AS/400. We'll never
know what might have become of Itanium if it hadn't been such a
committee enterprise. The 8080, after all, was not a particularly
superior processor design, and nobody needed *it*, either.
You keep saying that, but so far you're alone in the woods. Maybe for the
codes you're interested in, you're right. ...but for most of us there are
surprises in life. We don't live it linearly.
I'm definitely not alone in the woods on this one, Keith. Go look at
Dally's papers on Brook and Stream. Take a minute and visit
gpgpu.org. I could dump you dozens of papers of people doing stuff
other than graphics on stream processors, and they are doing a helluva
lot of graphics, easily found with google, gpgpu, or by checking out
siggraph conferences. Network processors are just another version of
the same story. Network processors are right at the soul of
mainstream computing, and they're going to move right onto the die.
With everything having turned into point-to-point links, computers
have turned into packet processors already. Current processing is the
equivalent of loading a container ship by hand-loading everything into
containers, loading them onto the container ship, and hand-unloading
at the other end. Only a matter of time before people figure out how
to leave things in the container for more of the trip, as the world
already does with physical cargo.
Power consumption matters. That's one point about BlueGene I've
conceded repeatedly and loudly.
Stream processors have the disadvantage that it's a wildly different
computing paradigm. I'd be worried if *I* had to propose and work
through the new ways of coding. Fortunately, I don't. It's
happening.
The harder question is *why* any of this is going to happen. A lower
power data center would be a very big deal, but nobody's going to do a
project like that from scratch. PC's are already plenty powerful
enough, or so the truism goes. I don't believe it, but somebody has
to come up with the killer app, and Sony apparently thinks they have
it. We'll see.
I worked (tangentially) on the original TMTA product. The "proof of
concept" was on MS Word. Let's call it "VC irrational exuberance". Yes
there was lots learned there, some of it interesting, but it came at a
time when Dr. Moore was still quite alive. Brute force won.
On the face of it, MS word doesn't seem like it should work because of
a huge number of unpredictable code paths. Turns out that even a word
processing program is fairly repetitive. Do you know if they included
exception and recovery in the analysis?
As usual, theory says that it and reality are the same. Reality has a
different opinion.
It's still worth understanding why. The only way to make things go
faster, beyond a certain point, is to make them predictable.
RM
Sun is currently claiming