Thursday, August 7, 2014

IBM's Neuromorphic processor chip

IBM’s SyNapse chip, as it is called, processes information using a network of just over one million “neurons,” which communicate with one another using electrical spikes—as actual neurons do. The chip uses the same basic components as today’s commercial chips—silicon transistors. But its transistors are configured to mimic the behavior of both neurons and the connections—synapses—between them.

The new chip is not yet a product, but it is powerful enough to work on real-world problems. In a demonstration at IBM’s Almaden research center, MIT Technology Review saw one recognize cars, people, and bicycles in video of a road intersection. A nearby laptop that had been programed to do the same task processed the footage 100 times slower than real time, and it consumed 100,000 times the power as the IBM chip. IBM researchers are now experimenting with connecting multiple SyNapse chips together, and they hope to build a supercomputer using thousands.
The power usage is significant. Human brain tissue may use more power per unit volume than any other tissue in the body, but it's still very low-powered compared to digital computers.
The efficiency of conventional computers is limited because they store data and program instructions in a block of memory that’s separate from the processor that carries out instructions. As the processor works through its instructions in a linear sequence, it has to constantly shuttle information back and forth from the memory store—a bottleneck that slows things down and wastes energy.

IBM’s new chip doesn’t have separate memory and processing blocks, because its neurons and synapses intertwine the two functions. And it doesn’t work on data in a linear sequence of operations; individual neurons simply fire when the spikes they receive from other neurons cause them to.
In his last book, The Computer and the Brain, John von Neumann speculated that each neuron was both a processing unit and memory.

Here's what I say about von Neumann's book in my post Computational Thinking and the Digital Critic: Part 1, Four Good Books:
Von Neumann was a mathematician who made contributions in many fields. But he is best known for his work in computing. This slender volume (82 pages) is the last project he worked on and is incomplete. Brain cancer took him before he could finish.

The book is about how a computing process can be embodied or implemented in physical matter, and discusses two modes, the analog and the digital, and, among other things, addresses the limitations these modes impose. Real computation is a material process. Therefore a computational approach to literature is materialist.

Though the book contains no math, it is quite abstract. Its details are at some remove from all the complex details about existing computers (then and now) or the messy wetware of the brain. That is to say, it is about the essential.

Forget about the fact that computers are now quite different from those von Neumann knew, and forget about the fact that most of what we know about the brain was discovered since von Neumann’s death. In this book a first-class mind grapples with deep questions in simple, if abstract, terms. Reading it is a good workout.

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