- The problem was that, as Google grew, its computing infrastructure also
expanded. Computer hardware rarely failed, until you had enough of it—then it
failed all the time. Wires wore down, hard drives fell apart, motherboards
overheated. Many machines never worked in the first place; some would
unaccountably grow slower. Strange environmental factors came into play.
- Solved by MapReduce
- Jeff once circulated a list of “Latency Numbers Every Programmer Should Know.” In fact, it’s a list of numbers that almost no programmer knows: that an L1 cache reference usually takes half a nanosecond, or that reading one megabyte sequentially from memory takes two hundred and fifty microseconds. These numbers are hardwired into Jeff’s and Sanjay’s brains.