Electrical power can be recovered from vibrations in the environment. There exist prototype energy scavenging devices -- they work by piezoelectric effects. It's like an electrical version of a flywheel. But that doesn't mean that your cell phone should buzz constantly to recharge its battery. To quote an oracle in our times:
Lisa, in this house we obey the laws of thermodynamics!
Floating-point arithmetic is not
fuzzy.It's an approximation of real arithmetic, but it's a self-consistent approximation. Some of the relations of the real numbers are preserved by floating-point arithmetic; those of us who use the arithmetic carefully utilize those preserved relationships.
Even on uniprocessors, the time to run a program will vary somewhat. Like good experimental scientists (which computer scientists often really are not) we run programs multiple times in order to determine the mean run time and standard deviation.
Asking me a question when I'm distracted and have not slept enough is a dangerous undertaking. I'm not the most talkative of people in a social situation, but I'll happily tell you what I know about a topic if you give me half a chance. Sometimes I'll tell you more than you really wanted to hear. When I'm distracted and have not slept, I'll tell you about all the other things I thought I should explain in the past few hours.
- Currently drinking: Black coffee.