So soddisfazioni:
http://www.linusakesson.net/programming/pipelogic/index.php
"Delightfully useless epiphany: Suppose the null-byte is an electron.
Then, /dev/zero provides an infinite supply of electrons and /dev/null
has an infinite appetite for them. Let's call these devices Vss and
Vdd, respectively.
In this model, a UNIX pipe acts like a wire, that is, a conductor with
parasitic capacitance. If the pipe is connected to Vss, its pipe
buffer in kernel space quickly fills up with null-bytes, and the pipe
acts like a negatively charged metal plate. If it is connected to Vdd,
the pipe buffer is drained, and the pipe acts like a positively
charged metal plate.
Pipes may thus carry logic signals: A pipe that is filled with
null-bytes corresponds to a logic zero, and a pipe that is completely
empty corresponds to a logic one. A pipe that contains some
null-bytes, but is neither full nor empty, corresponds to a voltage in
the undefined range, and will act as a one or a zero depending on how
we measure it."
