Screen-labeled function keys: Difference between revisions

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[[Image:ATMscreen.jpg|thumb|right|300px|ATM in [[Mercer Island, Washington]] with function keys]]
 
'''Screen-labeled function keys''' are a special case of [[function keys]] where keys are placed near a screen, which provides labels for them. These are most commonly found in kiosk applications, such as [[automated teller machine]]s and [[gas pump]]s. They originated in aviation cockpits, such as the [[F-111]] in the late 1960s/early 1970s.{{Citation needed|date=May 2012}}. [[Hewlett-Packard]] developed them for use in computers/calculators in the 1970s.{{Citation needed|date=September 2008}} The [[HP 9830]] desktop computer was the first calculator with two rows of 4 keys, over which a paper overlay would be placed. These were later adapted to terminals. Programmers found that the [[HP 2640]] terminals could lock the top two lines of the screen, so they displayed the key functions there. Starting with [[HP 2647]] terminal, the keys were re-arranged to correspond with 2 pairs of 4 labels at the bottom of the screen. These could be programmed by [[escape sequence]] or [[configuration screen]]. This would be further developed on the failed [[HP 300]] Amigo, which used keys at the right side of the screen and [[HP 250]] business computers which placed them at the bottom. By arranging functions in hierarchical trees, many functions can be implemented with only 8 keys.
 
==Graphical calculators==