- Green-screen display
Green screen was the common name for a
monochrome CRTcomputer display using agreen "P1"phosphor screen.Abundant in the early-to-mid-
1980s , they succeededteletype terminals and preceded colour CRTs as the predominant visual output device for computers.The most famous green screen product is arguably the original
IBM PC monochrome display, designated theIBM 5151 (the PC itself had the model number 5150). From the outset, the 5151 was designed to work with the PC's Monochrome Display Adapter (MDA) text-onlygraphics card , but soon the third-partyHercules Graphics Card became a popular companion to the 5151 screen because of the Hercules' high-resolutionbitmap ped monochrome graphics capability, much used for business presentation graphics generated from e.g.spreadsheet s likeLotus 1-2-3 .Some green screen displays were furnished with a particularly full/intense phosphor coating, making the characters very clear and sharply defined (thus easy to read), but generating a somewhat disturbing afterglow-effect (sometimes called a "ghost image") when the text
scroll ed down the screen or when a screenful of information was quickly replaced with another as inword processing page up/down operations. Other green screens avoided the heavy afterglow-effects, but at the cost of much morepixel ated character images. The 5151, amongst others, had brightness and contrast controls to allow the user to set their own compromise.The ghosting effects of the now-obsolete green screens have become an eye-catching visual shorthand for computer-generated text, frequently (and ironically) in "futuristic" settings. The Ghost in the Shell and the
Matrix source code of theMatrix trilogy science fiction film s prominently feature computer displays with ghosting green text. TheXScreenSaver package ofscreen saver s byJamie Zawinski also includes a screen saver called "Phosphor" that prints green text with a simulated ghosting effect. Green text is also featured in 's computer in "Lost" series.See also
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IBM 3270
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