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The Epic Interactive Encyclopedia 1998
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Epic Interactive Encyclopedia, The - 1998 Edition (1998)(Epic Marketing).iso
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Light_pen
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INFOTEXT
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1992-09-03
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558b
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14 lines
In computing, an input device resembling an
ordinary pen, used to indicate locations on a
computer screen. With certain computer-aided
design (CAD) programs, the light pen can be
used to instruct the computer to change the
shape, size, position, and colours of
sections of a screen image. At its tip, the
pen has a photoreceptor which emits signals
as light from the screen passes beneath it.
From the timing of this signal and a gridlike
representation of the screen in the
computer's memory, a computer program can
calculate the position of the light pen.