The memory in a computer's
graphics adaptor, used
to store the image displayed on a
bitmap display. Often
this is built using
VRAM chips. There is normally a simple
correspondence between groups of bits in video memory and
the dots or "pixels" on the screen, such that writing to a
given group of bits will alter the appearance of a single dot.
If each pixel corresponds to eight bits then it can have any
of 256 colours (or shades of grey on a monochrome display).
The video display electronics is responsible for reading the
data from video memory and converting it into the necessary
signals to drive the display. Often this includes a
colour palette which converts pixel values into
RGB triplets.