green screen

Also a computer monitor which can only display the color green. These were common on old terminals and early PCs. So were amber screens.

A green screen is a CRT with only green phosphor, much like that found on older oscilloscope tubes.

Use a green screen and you will be in some bizarre sort of hacker nirvana. I don't know quite what it is about them... they're truly magical. Most green screens are coupled to display adapters that only do text and usually simple graphics, further making the use of a green screen a Zen exercise.

Green screens are peace.

Green screens are power.

ASCII FOREVER!

Refers to user-facing software written for monochrome terminal systems, such as IBM 3270 and 5250 terminals. Typically these are legacy systems written for the mainframe or an AS/400. These apps were often written in RPG or COBOL or with special-purpose tools such as ISPF or even in SNOBOL. It is not uncommon for such apps to have single-page forms with dozens or even hundreds of input fields, which was the style at the time.

The term is used to distinguish between such systems and 'modern' browser-based front ends using HTML and PHP, Active Server Pages, or JavaServer Pages.

A special sort of application known as a screen scraper can be used to cruft an HTML front-end onto the green screen. The 'scraper' translates the user's input (often including an ASCII to EDB-CDIC transformation) and 'types' it into the green screen interface as if it were the user. Scrapers can also read the data off a green screen to pass it to newer Java or Windows applications.

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As greenscreen (q.v.) the term refers to the entertainment industry's process devised for video chroma key matting.