function key definition hardware
(From the IBM 3270
terminal's Programmed Function Keys (PF keys)) One of a set of special keys on a computer or terminal
keyboard which can be programmed so as to cause an application program
to perform certain actions.
Function keys on a terminal may either generate short fixed sequences of characters, often beginning with the escape
27), or the characters they generate may be configured by sending special character sequences to the terminal.
On a microcomputer
keyboard, the function keys may generate a fixed, single byte code, outside the normal ASCII
range, which is translated into some other configurable sequence by the keyboard device driver
or interpreted directly by the application program