Video Graphics Array (VGA) is a computer
display standard first marketed in 1987 by IBM. VGA belongs to a
family of earlier IBM video standards and largely remains backward
compatible with them. VGA can be seen as an enhancement of and
successor to the previous EGA and CGA graphics adapters. MCGA, also
produced by IBM, is a simpler version of the VGA hardware.
SVGA was extended from VGA, defined by Video Electronics Standards
Association instead of IBM.
VGA is referred to as an "array" instead of an "adapter" because it
was implemented from the start as a single chip (a gate array),
replacing the Motorola 6845 and a full-length ISA board full of
discrete components that the MDA, CGA, and EGA used. This also
allowed it to be placed directly on a PC's motherboard with a
minimum of difficulty (it only required video memory, timing
crystals and an external RAMDAC), and the first PS/2 models were
equipped with VGA on the motherboard. Since it wasn't restricted to
being an add-on board, the name refers to the chip itself.
As with most IBM hardware the VGA was extensively cloned by other
manufacturers. While the VGA in its original form has been obsolete
for some time, it was the last IBM standard that the majority of PC
clone manufacturers decided to follow, making it the only standard
graphics interface that can be relied on to be present on the PC
architecture. VGA was technically superseded by IBM's XGA standard,
but in reality it was superseded by the numerous extensions to VGA
by clone manufacturers that came to be known as Super VGA.
VGA remains a relevant graphics standard. It forms the "lowest
common denominator" that all PC graphics cards need to support
prior to a device-specific driver being loaded. On Windows
machines, the Microsoft Windows splash screen appears while the
machine is still operating in VGA mode, which is the reason that
this screen always appears in reduced resolution and color depth
compared to following screens.
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