The Advent of Advanced Display Systems
Graphics artists, engineering designers, and users who work with photorealistic images need more than a coarse, 16-color display. To tap into this market, which was using $40,000 workstations, PC vendors needed more powerful display systems. IBM offered a short-lived and very complicated engineering display adapter, the Professional Graphics Adapter (PGA). It required three ISA (Industry Standard Architecture) slots, and provided limited three-dimensional manipulation and 60 frames-per-second animation of a series of images. It was also very expensive and a dismal failure in the marketplace.
The reason was the advent of the Video Graphics Array (VGA) standard. All the preceding cards were digital devices; the VGA produced an analog signal. That required new cards, new monitors, and a 15-pin female connector. It allowed developers to produce cards that provided the user with up to 262,144 colors and resolutions up to 640 x 480.
The VGA card quickly became commonplace for a PC display system, and the race was on to produce cards with more colors, more resolution, and additional features. VESA (Video Electronics Standards Association) agreed on a standard list of display modes that extended VGA into the high-resolution world of color and high photographic quality we know today. The standard is known as SVGA (Super VGA). The SVGA sets specifications for resolution, refresh rates, and color depth for compatible adapters. On Pentium and later PCs, an SVGA adapter is the standard for display adapters. The minimum resolution needed for SVGA compatibility is 640 x 480 with 256 colors, and most modern adapters usually go far beyond that.