Can Our Computers Continue To Get Smaller and More Powerful?

aarondubrow (1866212) writes In a [note, paywalled] review article in this week's issue of the journal Nature (described in a National Science Foundation press release), Igor Markov of the University of Michigan/Google reviews limiting factors in the development of computing systems to help determine what is achievable, in principle and in practice, using today's and emerging technologies. "Understanding these important limits," says Markov, "will help us to bet on the right new techniques and technologies." Ars Technica does a great job of expanding on the various limitations that Markov describes, and the ways in which engineering can push back against them.

Comments

Obvious

[Russ1642]

Yes. Next question please.

Re:Obvious

[ShanghaiBill]

Did our jets get faster and lighter and cheaper?

The fastest air breathing aircraft was the SR-71, which went into production in 1962, based on technology from the 1950s. So for at least half a century, jets did not get faster. Aircraft improved enormously between 1903 and 1960. Then the rate of improvements fell off a cliff. That is why Sci-Fi from that era often extrapolated the improvements into flying cars, and fast space travel, but far fewer predicted things like the Internet or Wikipedia.

What's after atoms?

Silicon lithography will hit its limits after a few more iterations. But nano-assembly techniques may allow silicon transistors to be even smaller. After that we may be able to move to carbon nanotube transistors, based on spintronics to lower the heat dissipation. There is still plenty of room at the bottom.

Re:Obvious

[bobbied]

If you read my comment.... I'm saying that we are very close to hitting the physical limits. In the past, the limits where set by the manufacturing process, but now we are becoming limited by the material, the size of the of silicon atoms.

There is basically only one way to reduce the current/power consumption of a device, make it smaller. A smaller logic gate takes less energy to switch states. We are rapidly approaching the size limits of the actual logic gates and are now doing gates measured in hundreds of atoms wide. You are not going to get that much smaller than a few hundred atoms wide. Which means the primary means of reducing power consumption is reaching it's physical limits. Producing gates that small also requires some seriously exacting lithography and doping processes, and we are just coming up the yield curve on some of these, so there is improvement still to come, but we are *almost* there now.

There are still possible power reducing technologies which remain to be fully developed, but they are theoretically not going to get us all that much more, or we'd have already been pushing them harder. So basic silicon technology is going to hit the physical limits of the material pretty soon.

Re:Obvious

[GrahamCox]

Then the rate of improvements fell off a cliff

That's only true if you're only judging it by outright speed, height, etc. Things have continued to improve in terms of efficiency, thrust-to-weight ratio, noise, cleanliness of fuel burn and above all, reliability.

The original RB211 turbofan (the first big fanjet of the type that all modern airliners use) had a total lifetime of 1,000 hours. Nowadays it's >33,000 hours. That's an incredible achievement. In 1970, as a young kid with a keen interest in aviation, I would watch Boeing 707s fly in and out of my local airport, all trailing plumes of black smoke, all whining loudly (and deafeningly, on take-off), and understanding where all the noise protesters that frequently appeared on the news were coming from. Nowadays you don't have that, because noise is just not the problem it was, there's no black smoke, and jets slip in and out of airports really very quietly, when you consider how much power they are producing (which in turn helps them climb away more quickly).

As far as computing is concerned, you're right - there's still plenty of room at the bottom. But the current fabrication technology is reaching its limits. Perhaps jet engine manufacturers in the late 60s couldn't see how they would overcome fundamental limits in materials technology to produce the jets we have today, but they did.

Re:Obvious

[dnavid]

Silicon lithography will hit its limits after a few more iterations. But nano-assembly techniques may allow silicon transistors to be even smaller. After that we may be able to move to carbon nanotube transistors, based on spintronics to lower the heat dissipation. There is still plenty of room at the bottom.

The point of the article and the article it references is that its easy to say stuff like that, but also mostly irrelevant to practical computing because in the history of modern computing its never been absolute physical limits that caused major changes to how computing is implemented. Just because there's room at the bottom, doesn't mean its room we can use. We *may* be able to use nano-assemblers for silicon and *may* be able to use carbon nanotube transistors, but unless that gets translated to someone working on actual practical implementations of those technologies, they will apply as much to the average consumer as the SR-71 that's being discussed in this thread means to the average commercial air traveler. In other words, exactly zero.

When I was in college people were already talking about the exotic technologies we would have to migrate to in order to achieve better performance, and that was the late eighties. In the twenty-plus years since then, we're still basically using silicon CMOS. Granted the fabrication technologies and gate technologies have radically improved, but the fundamental manufacturing technology is still the same. Its been the same because there's hundreds of billion dollars of cumulative technological infrastructure and innovation behind silicon lithography. For these other "room at the bottom" technologies to be meaningful, and not just SR-71s, they need to be able to reach the same point silicon lithography with its multi-decade head start and approaching trillion dollar learning curve. Its not enough to just work in theory, or even in practice one-off. If it can't work at the scale and scope of silicon lithography, its just an SR-71. A cool museum piece of advanced technology almost no one will ever see, touch, use, or directly benefit from.

It isn't trivially obvious there exists a technology commercializable in the next few decades that can replace silicon lithography. Anyone who thinks that's obvious doesn't understand the practical realities of scaling these technologies.

Bettridge vs Moore in the battle of the laws

[raymorris]

Bettridge's law says no.
Moore's law says yes.

In the battle of the eponymous laws, which law rules supreme? Find out in this week's epoch TFA.

Re:Bettridge vs Moore in the battle of the laws

[riverat1]

In the battle of the eponymous laws, which law rules supreme?

Murphy's Law.

yes. Especially per passenger.

[raymorris]

> Did our jets get faster and lighter and cheaper?

Yes. Especially lighter and cheaper PER PASSENGER, which is the goal for passenger jets.

> it still takes the same amount of energy to fly across the Atlantic.

Nope, fuel efficiency and energy efficiency have improved significantly.

Re:performance never measured in MHz

[vux984]

three decades in the industry and I've never seen performance measured or stated in MHz

Erm... from the 80286 through the Pentium 3 CPU clockspeed was pretty much THE proxy stat for "PC performance".

Our own computers? In the FUTURE?

[uCallHimDrJ0NES]

Next you'll be telling me they'll let us run unsigned code on processors capable of doing so. You need to get onboard, citizens. All fast processing is to occur in monitored silos. Slow processing can be delegated to the personal level, but only with crippled processors that cannot run code that hasn't yet been registered with the authorities and digitally signed. You kids ask the wrong questions. Ungood.