In The Hitchhiker’s Guide to the Galaxy, Douglas Adams mentions an extremely dull planet, inhabited by a bunch of depressed humans and a certain breed of animals with sharp teeth which communicate with the humans by biting them very hard in the thighs. This is strikingly similar to UNIX, in which the kernel communicates with processes by sending paralyzing or deadly signals to them. Processes may intercept some of the signals, and try to adapt to the situation, but most of them don’t. — The TTY demystified