Chapter 23. Concurrency

For several decades, microprocessor development has followed Moore’s Law. This is an observation by Gordon Moore that the number of transistors that you can fit on a chip, for a fixed cost, doubles roughly every 18 months.

There are a number of results of this. One is that the cost of chips goes down over time. Something like the iPhone has a faster CPU than the first desktop machines OS X ran on, but costs a fraction of the price. The second is that processors tend to get faster.

One of the ways that this benefited programmers was the addition of extra instructions. Early microprocessors couldn’t do floating point operations in hardware. If you wanted to add two floating point numbers together you had to split them into ...

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