Video, Graphics Cards

A Graphics Processing Unit or GPU (also occasionally called Visual Processing Unit or VPU) is a dedicated graphics rendering device for a personal computer, workstation, or game console. more...

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Modern GPUs are very efficient at manipulating and displaying computer graphics, and their highly parallel structure makes them more effective than typical CPUs for a range of complex algorithms.

A GPU implements a number of graphics primitive operations in a way that makes running them much faster than drawing directly to the screen with the host CPU. The most common operations for early 2D computer graphics include the BitBLT operation (combine two bitmap patterns using a RasterOp), usually in special hardware called a "blitter", and operations for drawing rectangles, triangles, circles, and arcs. Modern GPUs also have support for 3D computer graphics, and typically include digital video-related functions as well.

History

1970s

Modern GPUs are descended from the monolithic graphic chips of the late 1970s and 1980s. These chips had limited BitBLT support in the form of sprites (if they had BitBLT support at all), and usually had no shape-drawing support. Some GPUs could run several operations in a display list, and could use DMA to reduce the load on the host processor; an early example was the ANTIC co-processor used in the Atari 800 and Atari 5200. In the late 1980s and early 1990s, high-speed, general-purpose microprocessors became popular for implementing high-end GPUs. Several high-end graphics boards for PCs and computer workstations used TI's TMS340 series (a 32-bit CPU optimized for graphics applications, with a frame buffer controller on-chip) to implement fast drawing functions; these were especially popular for CAD applications. Also, many laser printers from Apple shipped with a PostScript raster image processor (a special case of a GPU) running on a Motorola 68000-series CPU, or a faster RISC CPU like the AMD 29000 or Intel i960. A few very specialised applications used digital signal processors for 3D support, such as Atari Games' Hard Drivin' and Race Drivin' games.

As chip process technology improved, it eventually became possible to move drawing and BitBLT functions onto the same board (and, eventually, into the same chip) as a regular frame buffer controller such as VGA. These cut-down "2D accelerators" were not as flexible as microprocessor-based GPUs, but were much easier to make and sell.

1980s

The Commodore Amiga was the first mass-market computer to include a blitter in its video hardware, and IBM's 8514 graphics system was one of the first PC video cards to implement 2D primitives in hardware.

The Amiga was unique, for the time, in that it featured what would now be recognised as a full video accelerator, offloading practically all video generation functions to hardware. This video hardware included a fast blitter, a hardware sprite engine, a display port scrolling engine and hardware resources to draw lines, fills and other primitives. Prior (and quite some time after on most systems) the CPU had to draw the display.

Read more at Wikipedia.org