First, Moore said that density would double every 18 months or so. He did not say performance would double. Second, lately it's harder to double so it is more like two years per doubling. Third, Moore's law won't continue for 40 more years. Trust me, I'm CTO at a semiconductor company J
Vertical scaling limits were hit a few years ago, which is why peak frequency stopped going up so fast. Once oxide thickness is down to about a dozen atoms there is no room to make it thinner without too much process variation and too much tunneling current. Voltage scaling limits were hit around the same time, around 1 volt, since the supply voltage has to be higher than the transistor threshold voltage. Without scaling voltage down, power becomes a limiter to performance. We have about 2 to 4 more doublings before planar transistors stop working. There are alternatives (google finfet), but they are much more difficult to fabricate, and in any case fets won't work with gates of only a few nanometers. Lithography also becomes a big issue soon. There is no inexpensive alternative to deep UV despite hundreds of millions of dollars spent on research on x-ray and scanning electron beams. No one has found a good lens for x-rays, and electron beams are too slow. Maximum die size grew in the early days, but has been constant for more than 10 years, so we can't grow the chip area. Die can be stacked, but this doesn't work well because silicon is not a great conductor of heat and the inner layers will overheat (and hot silicon is slow silicon). Someone will mention alternatives to silicon like carbon nanotubes, but these are just speculation. It took silicon technology 40 years of active development by the whole industry to get where it is now. Nothing else is even close to being feasible. I think we will get another 64x to 256 x density then it will stop, for single chips. We should eventually get desktop machines with thousands of cores, but probably never with millions of cores. There really are limits built into physics L David From: [email protected] [mailto:[email protected]] On Behalf Of terry mcintyre Sent: Wednesday, June 10, 2009 11:04 PM To: computer-go Subject: Re: [computer-go] MCTS, 19x19, hitting a wall? _____ From: Don Dailey <[email protected]> > My basic observation is that over the several year period I have been in this forum, I have detected a huge amount of resistance to the idea that hardware could have anything to do with computer go strength, despite the fact that it keeps proving to be so. The resistance is strong enough that we have to explain it way when it happens, by saying things like we have hit a wall and it won't happen any more thank goodness. You overrstate the "resistance" - it's not that anybody is saying hardware is irrelevant. In fact, did we not have a recent discussion over the merits of two different CPU variations? We've seen a fair number of multi-processor entrants at competitions, besides. The questions is"how much does hardware matter?" So far, we have one data point to work with: David Fotland's excellent Many Faces of Go is "about one stone stronger" when it uses 32 cores instead of 2. That's nice to have, but if we extrapolate, a factor of 16 is 3 doublings or about 4.5 years, in terms of Moore's Law. It will only take 9*4.5, roughly 40 years, to reach pro-level play. We don't have data from Mogo yet, but I wonder if they are seeing 2-3 stones improvement for their 3200-node version? The less patient among us may wish to seek algorithmic improvements to bridge the gap a bit sooner. Got to be some reason for bright programmers and mathematicians to work on the problen, after all; otherwise we could just wait 40 years for Intel and AMD to deliver 32,768 cores on a single chip - or will it be a silicon wafer? In other fields, algorithmic improvements have led multiple orders of magnitude improvement in running time. Humans manage to complete 30-minute games on a 19x19 board, so we do have evidence that the game can be played well at such a speedy pace.
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