VGA

VGA, short for Video Graphics Array, is a PC display standard and connector defined by IBM in 1987 for graphics hardware. It succeeded CGA and EGA, offering higher resolution, color depth, and more flexible timing. The interface uses a 15-pin D-sub connector (DE-15) delivering analog RGB video plus horizontal and vertical synchronization.

VGA supports multiple display modes. The most widely used are 640x480 resolution with 16 colors and 320x200 with 256 colors; typical refresh rates are 60 Hz. In 256-color mode, each pixel is addressed by an 8-bit color index that selects a palette of up to 262,144 colors defined by the video BIOS. VGA is an analog standard, transmitting three color channels (red, green, blue) and synchronization signals over the connector. Although the original specification defined specific modes, implementations exploited various timings and extended palettes via BIOS software; the term SVGA was later used to describe higher resolutions while remaining backwards compatible with VGA.

Impact and legacy: VGA became the de facto PC video standard through the 1990s and remained common on desktops and laptops for many years, aided by simple cables and broad compatibility. With the rise of digital interfaces—DVI, HDMI, DisplayPort—the use of VGA declined, but many devices still provide a VGA port or support VGA over adapters. Signal quality depends on cable length and interference, since it is an analog signal.