Re: RC Transmission Lines (Wafer-Scale)

John Larkin wrote:
On Mon, 22 Oct 2007 12:59:19 -0400, Phil Hobbs
<pcdh@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On the other hand, there are enough customers for the fastest machines (who know very well what they need) to keep me in beer and skittles, anyway. I like doing things that are useful and fun. Why do you do what you do?

It's ironic that most of the compute power in the world goes to
gaming. The most compute-intensive thing we do, in fact the only
compute-intensive thing we do, is fpga p+r. Design-rule checking the
most complex pc board we make takes about 5 seconds on a
standard-performance PC. The rest of what we do is dominated by our
DSL rate.

Whatzisname's law: All computers wait at the same speed.


Even Spice usually runs fast. I guess em simulation could be slow, but
we rarely do that, thank Goodness.

Done the simple-minded way (the way I'd like to do it if I could), one device design comes out as something like

10**9 cells x 32 bytes x 2 FLOP/byte x 200 steps/cycle x 100 cycles/run x 100 runs/design =~ 10**17 operations

per design, running in about 32 gig of memory. Could take awhile, even on a fast parallel machine. The 200 steps/cycle number is needed only when using silver--because the real part of its index of refraction is only about 0.1, so the phase velocity in silver is almost 10 times c.


Intel must be running scared; some day pc's will be good enough and
become as exciting as toasters, and $5 Taiwanese cpu's will be
powerful enough.

PCs are already less exciting than toasters--in both good and bad senses. My microprocessor-controlled toaster has buttons for toasting bagels and frozen bread, which usually more or less work if it starts out cold, but I never used to worry about my mechanical toaster crashing and having to be rebooted (which happens about once a week with this one). My cluster needs rebooting about twice a year, but doesn't make good toast.

Commoditization is the eventual fate of just about every technology, and the whole industry has been scrambling for many years to stay high on the food chain. IBM gave up making displays, PCs, and disc drives mostly for that reason.

On the other hand, having the best-performing and most reliable servers is really important to us, partly because of the price premium, but also because it drags along a lot of software and consulting revenue. That's one reason that I've been working on high performance, low power optical interconnections: in a highly multiprocessor world, bandwidth needs to grow at least as the square of the number of processor cores if you're going to keep tight coupling between cores. That tight coupling is really important because most applications don't parallelize terribly well, and tight coupling is the only way to keep the average performance up. Tightly coupled machines are dramatically easier to program, which is another way of saying the same thing.

It's the software fads that will keep CPU demand going...it's amazing how many computrons you can soak up by using the revolutionary interpreted language-du-jour. Good luck running anything written in Java on even a vanilla Pentium. (Remember when everybody made fun of Intel for that name?)

Cheers,

Phil Hobbs
.