Sunday, April 16, 2017

The Coming Interregnum after Moore's Law

An interregnum is a gap in governance, most commonly when a monarch dies without a child old enough to take over.  For decades the world has grown used to the idea that computers would get better and better year by year as engineers were able to fit more and more transistors onto a piece of silicon economically in a process described by Moore's Law.  Sadly, that law looks to be running out of steam.  So we're going to have to go through an interregnum while people discover some other substrate for computation that can be pushed further than silicon transistors could.

Transistors have come a long way since they were invented in 1926.  They couldn't be built by the people who conceived them but in 1947 Shockley et al figured out how to make a practical transistor for use various electronics such as radios and then in 1954 the first transistorized computer was developed: TRADIC.  It was an amazing device at the time because computers were usually room sized whereas TRADIC was only the size of a refrigerator.  It also consumed only 100 Watts of power instead of many kilowatts and was nearly as fast as the best computer built with the then standard vacuum tube.  Sadly transistors were still much more expensive than vacuum tubes.

Then, in 1959 people built the first silicon chip with more than one transistor on it.  People started putting more and more, smaller and smaller transistors on pieces of silicon.  In 1965 Gordon Moore noticed what was happening and predicted that by 1975 people could fit over 65,000 transistors on a single chip.  Sure enough the size of transistors continued to shrink exponentially and in 1975 people were stating to talk about "Moore's Law."

And ever since then the size of transistors has shrunk by a factor of two more or less every 18 months.  For a very long time, until 2005 or so, shrinking transistors brought faster clock speeds.  The amount that transistor leak is governed by the voltage used in them and the size of the gate and until we hit 90 nanometers in 2005 the amount that transistors leaked was tiny compared to the amount of power required to flip them from a 0 to a 1 so everybody left the voltage the same.  Ever since then we've had to worry about leakage currents much bigger than switching currents and so we've shrunk voltage at the cost of no longer increasing clock speeds.  A piece of silicon can only dissipate so much heat per square centimeter.

And now the shrinkage of the transistors themselves looks like it will begin failing.   Here's a Nature article from last year predicting in demise.  Here's Sophie Wilson, the genius behind the original ARM processor saying she doesn't think there's that much time left.  And now Intel has repeatedly delayed moving off of 14 nanometers with constantly slipping deadlines for Cannonlake, its first 10 nanometer chip.  The end is not yet but it looks like it'll certainly be here by 2025.

Thankfully there's good reason to believe that this isn't anything like the end of progress in computation.  For a long time steam engines became more efficient periodically but eventually that stopped because there's a fundamental limit to how efficient an engine can be bounded by an ideal called the Carnot cycle.  When engines got close to that bound progress slowed down.

Luckily there are firm physical limits we understand to how efficiently you can perform computation and we still have a ways to go.  Current gates in high end silicon take around an attoJoule to perform a simple 'and' or 'or' computation but Landauer's Principle says that it's possible to do it for 2.75 zeptoJoules, 500 times less.  And thankfully by reducing the ambient temperature we should be able to do better.  Regarding speed there's another limit, Bremermann's, that we're even further from.

So what could take the place of Moore's law?  Off the top of my head different substrates such as diamond or carbon nanotubes.  Computation through magnetic spin.  Computation through photons.  Quantum computers.   Ballistic electrons.  Nano-mechanical systems.  Nano-electro-mechanical systems.  Pure chemical systems like DNA computing.  There are quite a few options and all are far from being ready for commercial use.  Still, there's no reason to think that we won't be able to make one of them work eventually.  In the mean time maybe we'll face stagnation or maybe we'll have a golden age of computer architecture where we learn to do more with the transistors we have.  Only time will tell.

Tuesday, April 4, 2017

Freedom of contract requires the government

There's a very real sense in which any sort of free market you could have can only exist when it is created by a government.  Without government there might be no third party to prevent me from selling my goods to the person over the hill but at the same time there's nothing preventing that person from just taking my goods and not paying me if he feels that he has a greater capacity for violence.  A world without government doesn't look like the "war of all against all" that Hobbes described in Leviathan since people still have their senses of friendship and kinship but those only extend so far.  Trading without the arm of the state to preclude violence takes trust that has to be built up over long periods of time and tends to occur in very stereotyped forms.  You can't run a modern supply multi-stage supply chain or anything like it without the umbrella of a state unless, against all odds, Nozick's ideas about capitalist anarchy actually work out in practice.

But beyond protecting us and our property from violence governments do something else to enable markets which I think is commonly underappreciated.  They're willing to enforce contracts.

Not all contracts of course.  You can't sell yourself into slavery, to take just one example.  But in general if you and another person come to a formal agreement then if one of you breaks it you can go to the government and it will use all its vast power to make sure the breaker either fulfills their obligations or pays up.  That's a lot of bother on the government's part but it's proven absolutely vital in the development of commercial economies and in the end led to success for the governments which were willing to go to that trouble.

Lets say that I'm really good at making widgets.  And this guy I know knows who wants to buy widgets.  Ideally we'd go into business together and form a widget company.  But if later I could learn from our business who was buying the widgets I could just drop my partner and sell to them directly.  Knowing this that guy might never go into business with me and might have to resort to complicated and inefficient means to prevent me from knowing who the buyers are.  So the ability to create a contract between us preventing this can make us both better off.

Or look at capital.  When I was reading Medieval Machines I was struck by how many of the milling developments in the high medieval era were the result of a bunch of people pooling their money into joint ventures like damning a river to use water power to grind grain.  Without prior and enforceable agreements as to who can use what how the development of large mechanical projects in Europe might not have gotten as far as it did as quickly as it did.

That the industrial revolution happened in Europe rather than China presents a bit of a puzzle.  China in wasn't as wealthy as England with as high wages, but the Yangtze delta was and that was an area as large as England.  Markets were about as free in China on average as they were in England.  The people were as educated though you can quibble about different emphases.  Coal, coal near population centers was certainly a difference I'll grant.  But another important difference was that the English bureaucracy wasn't nearly as selective as the Chinese one.

The idea of selecting officials by written examination was introduced early in Chinese history and it worked really, amazingly well allowing China to amass a unified state far larger than its neighbors and create far greater prosperity as well.  But the very selectiveness of China's meritocracy ended up being a problem because by the early modern era France and England had been expanding their bureaucracies to have roughly ten times as many officials per capita as Russia or China did.  The quality might not have been as high as in China but greater numbers meant more attention to more things and part of that was the enforcement of commercial law between merchants.

In theory Chinese merchants could have contracts but in practice the courts were busy and couldn't be bothered.  There were stories of merchants pretending that a murder had occurred in order to get a judge to see them so they could ask the judge to adjudicate a commercial dispute.  And I wonder if that, along with China's coal deposits being far away from its developed areas, can explain why the industrial revolution happened in Europe.

In the modern day we still see that different people have different access to commercial law, though basically every country cares about it at least in theory.  Fernando de Soto wrote a book, The Mystery of Capital, on how in many third world countries capitalism exists for the rich but not for the poor who have no title to their property and no real access to the court system.  The elites have real contracts but the poor don't and as a consequence inequality is redoubled.

One heartening trend in recent year is the introduction of widespread biometrics in India.  This is still a long way from all the tools of capitalism being widely available but legal identity is the first step and is an encouraging sign.

UPDATE:  And this is the sort of thing that identity provided by biometrics could hopefully help with.  Enough people have been declared legally dead and their land seized that there's a support group for them.

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