from
The Free On-line Dictionary of Computing (8 July 2008)
feedback control
<electronics> A control system which monitors its effect on
the system it is controlling and modifies its output
accordingly. For example, a thermostat has two inputs: the
desired temperature and the current temperature (the latter is
the feedback). The output of the thermostat changes so as to
try to equalise the two inputs.
Computer {disk drives} use feedback control to position the
read/write heads accurately on a recording track. Complex
systems such as the human body contain many feedback systems
that interact with each other; the homeostasis mechanisms that
control body temperature and acidity are good examples.
(1996-01-02)