In the 1950s I spent a significant chunk of my pocket money buying a transistor. It was a small metal cylinder (about 5mm in diameter and 7mm deep) with three wires protruding from its base. I needed it for a little radio I was building, and buying it was a big deal for a lad living in rural Ireland. My baffled parents couldn’t understand why this gizmo their son was holding between finger and thumb could be interesting; and, to be honest, you couldn’t blame them.
Now spool forward six decades. The A13 processor that powers the iPhone that I used to find a photograph of that first transistor has 8.5 billion of them etched on to a sliver of silicon no bigger than a fingernail – a “chip”. The next generation of these chips will have transistors almost as small as the diameter of a human chromosome.
This ability to cram more and more transistors into a finite space is what gave us Moore’s law – the observation that the number of transistors in an integrated circuit will double every two years or so – and with it the fact that computer power has been doubling every two years for as long as most of us can remember. The story of how this happened is a riveting tale of engineering and manufacturing brilliance and is brilliantly told by Chris Miller in his bestselling book Chip War, which should be required reading for all Tory ministers who fantasise about making “Global Britain” a tech superpower.
But with that long run of technological progress came complacency and hubris. We got to the point of thinking that if all that was needed to solve a pressing problem was more computing power, then we could consider it solved; not today, perhaps, but certainly tomorrow.
There are at least three things wrong with this. The first is that many of humankind’s most pressing problems cannot be solved by computing. This is news to Silicon Valley, but it happens to be true. The second is that Moore’s law will soon run up against the laws of physics. We’re getting to the point where the critical part of a transistor – the “gate” through which current flows – is approaching 2 nanometers (nm – a billionth of a metre) and a silicon atom is 0.2nm in diameter, which means that the gate is only about 10 silicon atoms wide, at which point all kinds of awkward interactions between atoms start to occur and manufacturing becomes really problematic.
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