Computing after Moore’s Law


Fifty years ago this month Gordon Moore published a historic paper with an amusingly casual title: “Cramming More Components onto Integrated Circuits.” The document was Moore’s first articulation of a principle that, after a little revision, became elevated to a law: Every two years the number of transistors on a computer chip will double.

As anyone with even a casual interest in computing knows, Moore’s law is responsible for the information age. “Integrated circuits make computers work,” writes John Pavlus in “The Search for a New Machine” in the May Scientific American,“but Moore’s law makes computers evolve.” People have been predicting the end of Moore’s law for decades and engineers have always come up with a way to keep the pace of progress alive. But there is reason to believe those engineers will soon run up against insurmountable obstacles. “Since 2000 chip engineers faced with these obstacles have been developing clever workarounds,” Pavlus writes, “but these stopgaps will not change the fact that silicon scaling has less than a decade left to live.”

Faced with this deadline, chip manufacturers are investing billions to study and develop new computing technologies. In his article Pavlus takes us on a tour of this research and development frenzy. Although it’s impossible to know which technology will surmount silicon—and there’s good reason to believe it will be a combination of technologies rather than any one breakthrough—we can take a look at the contenders. Here’s a quick survey.

Graphene
One of the more radical moves a manufacturer of silicon computer chips could make would be to ditch silicon altogether. It’s not likely to happen soon but last year IBM did announce that it was spending $3 billion to look for alternatives. The most obvious candidate is—what else?—graphene, single-atom sheets of carbon. “Like silicon,” Pavlus writes, “graphene has electronically useful properties that remain stable under a wide range of temperatures. Even better, electrons zoom through it at relativistic speeds. And most crucially, it scales—at least in the laboratory. Graphene transistors have been built that can operate hundreds or even thousands of times faster than the top-performing silicon devices, at reasonable power density, even below the five-nanometer threshold in which silicon goes quantum.” A significant problem, however, is that graphene doesn’t have a band gap—the quantum property that makes it possible to turn a transistor from on to off.

Carbon Nanotubes
Roll a single-atom sheet of carbon into a cylinder and the situation improves: carbon nanotubes develop a band gap and, along with it, some semiconducting properties. But Pavlus found that even the researchers charged with developing carbon nanotube–based computing had their doubts. “Carbon nanotubes are delicate structures,” he writes. “If a nanotube’s diameter or chirality—the angle at which its carbon atoms are “rolled”—varies by even a tiny amount, its band gap may vanish, rendering it useless as a digital circuit element. Engineers must also be able to place nanotubes by the billions into neat rows just a few nanometers apart, using the same technology that silicon fabs rely on now.”

Memristors
Hewlett–Packard is developing chips based on an entirely new type of electronic component: the memristor. Predicted in 1971 but only developed in 2008, memristors—the term is a portmanteau combining “memory” and “resistor”—possess the strange ability to “remember” how much current previously flowed through it. As Pavlus explains, memristors make it possible to combine storage and random-access memory. “The common metaphor of the CPU as a computer’s ‘brain’ would become more accurate with memristors instead of transistors because the former actually work more like neurons—they transmit and encode information as well as store it,” he writes.

Cognitive Computers
To build chips “at least as ‘smart’ [as a] housefly,” researchers in IBM’s cognitive computing group are exploring processors that ditch the calculator like Von Neumann architecture. Instead, as Pavlus explains, they “mimic cortical columns in the mammalian brain, which process, transmit and store information in the same structure, with no bus bottlenecking the connection.” The result is IBM’s TrueNorth chip, in which five billion transistors model a million neurons linked by 256 million synaptic connections. “What that arrangement buys,” Pavlus writes, “is real-time pattern-matching performance on the energy budget of a laser pointer.”

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California coastline hosts ‘Great Pacific Garbage Patch’


Tons of plastic have accumulated in an area between Hawaii and California, and the convergence of currents swirls the trash into what is now known as the Great Pacific Garbage Patch.

Bottle caps, trash bags and broken plastic are now part of the diet of many birds and sea creatures around the world.

It’s very depressing, initially, to realize the extent of the problem,” said Captain Charles Moore, founder of Alagalita Marine Research Institute.

One of the largest concentrations of marine debris is in the Pacific Ocean, halfway between Hawaii and California. It’s called the Great Pacific Garbage Patch.

Moore accidentally found the garbage patch in 1997 while sailing through a gyre, where ocean currents circulate and accumulate trash.

It’s a piece here, a piece there. It’s not a solid island. In general what we see is a soup of plastic. Not really an island of plastic,” said Moore.

Next year, Captain Moore is planning to spend a month at the Garbage Patch to research its effects on the food chain.

It is difficult to see the collection of trash from above because it’s made up of pieces of plastic the size of a finger nail. Researchers believe that there could be 2 million of these little pieces of plastic per square mile.

Millions of creatures are dying every year, tangled in plastic,” said Moore.

It’s not just the wildlife that is being fooled into eating this stuff and getting tangled in it, it’s we ourselves that are changing our biological being with these chemicals in this hyper-consumptive world that we live in,” Moore added.

Scientists at the Scripps Institution of Oceanography in San Diego have also been trying to figure out how the marine debris is changing the world. A Scripps study estimated that fish in the intermediate ocean depths of the North Pacific Ocean ingest plastic at a rate of roughly 12,000 to 24,000 tons per year.

Cleaning up the mess that’s already been made is likely impossible, but experts believe the problem could potentially be saved with a radical change in economic and social culture.

When you hear politicians talk about growth, you would think it’s one of the 10 Commandments,” said Moore.

Our very being is consumers of products. This defines us these days. The type of car we have, the type of shoes we wear. The type of hair gel we do. The band of clothing we have. This is how we get our identity,” Moore added.

Moore argues that consumption habits and our creature comforts have led to an earth shattering problem: where to put all of the trash we generate.

We have to really redefine ourselves as human beings, as something other than a consumer in order to beat this problem,” said Moore.

New shorelines created of trash are appearing in all oceans, and even in America’s Great Lakes.

As world economies continue to thrive on mass consumption, Captain Moore will continue to sail and study the plastic oceans.