Professional Graphics Controller was a graphics card manufactured by IBM for the PC. It was very advanced for its time, providing both 2D and 3D graphics acceleration for CAD applications. It consisted of three interconnected PCBs, and contained its own processor and memory.
The PGC's matching display was the IBM 5175, an analog RGB monitor that is unique to it and not compatible with any other video card without modification. With hardware modification [1], the 5175 can be used with VGA, Macintosh, and various other analog RGB video sources. Some surplus 5175's in VGA-converted form were sold by catalog retailers such as COMB in the early 1990's[citation needed].
Introduced in 1984, the Professional Graphics Controller (often called "Professional Graphics Adapter" and sometimes "Professional Graphics Array") offered higher resolution and color depth than EGA, and supported 256 colors at higher resolutions than VGA, supporting resolutions up to 640×480 with 256 colors at 60 frames per second. This mode is not BIOS-supported. It was intended for the computer-aided design market and included 320 kB of display RAM and an on-board 8088 microprocessor, which gave it the ability to do 3D rotation and clipping of images. While never widespread in consumer-class personal computers, its US $4,290 list price compared favorably to US$50,000 dedicated CAD workstations of the time. It was discontinued in 1987 with the arrival of VGA.
The display adapter was composed of three physical circuit boards (one with the on-board microprocessor, firmware ROMs and video output connector, one providing CGA emulation, and the third mostly carrying RAM) and occupied two adjacent expansion slots on the XT or AT motherboard; the third card was located in between the two slots. The PGC could not be used in the original IBM PC due to the spacing of its slots.
In addition to its native 640 x 480 mode, the PGC optionally supported the documented text and graphics modes of the Color Graphics Adapter, which could be enabled/disabled using an onboard jumper. However, it was not register-compatible with CGA.
References
- Mueller, Scott (1992) Upgrading and Repairing PCs, Second Edition, Que Books, ISBN 0-88022-856-3 - which says 3 slots and "adapter"
- A Professional Graphics Controller by K. A. Duke and W. A. Wall, IBM Systems Journal
- Professional Graphics Adapter pictures which says 2 slots
External links
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