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Encyclopedia > IBM 2250

The IBM 2250 Graphics Display Unit was announced as part of System/360 in 1964. Unlike most modern computer displays, which show images in raster format, the IBM 2250 used vector graphics. A display list of line segments (vectors) on a 1024 by 1024 grid was stored in the computer's memory and repainted on the 2250's CRT up to 40 time per second. Characters were built of line segments specified by display list subroutines. Thus any character set or font could be displayed. The computer altered the display by changing the display list. As the display list got longer, the refresh time got longer too and eventually the display would start to flicker.


The 2250 was housed in a desk with an alphanumeric (QWERTY) keyboard and a separate programmed function keyboard which had keys, indicator lights and switches. A plastic overlay label could be placed over the function keyboard. Punches on the top edge of the overlay could be sensed by the computer so the keys, lights and switches could be reprogrammed simply by changing overlays. The 2250's CRT measured 21" diagonal, but the useful display area was 12 inch by 12 inch. A light pen was provided as a pointing device, serving the function of the modern computer mouse.


An IBM 2285 Display Copier could be attached to the 2250 to provide 8-1/2 by 11 inch hard copy of the display contents under operator control.


  Results from FactBites:
 
The IBM 2250 Display Unit (549 words)
The IBM 2250 Display Unit was originally shipped with the IBM 1130 computer, introduced in 1965.
Columbia's 2250 was intended for use by physicists to read, display, and interact with cloud chamber photos, from ongoing physics experiments in the machine room (the 360/91 was largely paid for from physics research grants).
IBM followed the 2250 with a 3250 vector graphics unit, and later (mid 1980s) by the 5080 raster graphics station.
IBM 2250 (258 words)
The IBM 2250 Graphics Display Unit was announced as part of System/360 in 1964.
The 2250 was housed in a desk with an alphanumeric (QWERTY) keyboard and a separate programmed function keyboard which had keys, indicator lights and switches.
An IBM 2285 Display Copier could be attached to the 2250 to provide 8-1/2 by 11 inch hard copy of the display contents under operator control.
  More results at FactBites »

 
 

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