Chapter 13. Concurrency

You've most likely heard of Moore's Law. In 1965, Gordon Moore noticed that the number of transistors that could be fit on a circuit board per square inch had doubled every year since their invention. Moore's Law was the name given to the belief that this would continue, albeit every 18 months. So far, this has been remarkably correct. The upshot is that computers are getting faster and smaller, and they use less power; one example is the ubiquity of mobile phones.

However, nothing lasts forever. The exponential growth in the context of processing power is already tailing off. If we are unable to continually make systems work faster by increasing raw speed, we must look for an alternative.

One such alternative is to split programs into parts that could run concurrently and then use multiple processors. Together, a collection of slower chips can perform as fast as one faster chip as long as the programs are able to parallelize their code to...