Visual display (graphics) adaptor

Visual display adaptor :
Printed Circuit Board installed in one of the PC's expansion slots

To display images on a screen requires a Display Adaptor

An associated driver is also required to be installed.

MS-DOS programs will usually require individual drivers with the application software.

c_vdu1.jpg (29901 bytes)

IBM Standard Display Adapters /settings

MDA Monochrome Display Adaptor (80 x 24 characters), usually Green, Amber or White.
Hercules Mono - 720 x 348 pixels
CGA Colour Graphics Adapter 16 Colours - 640 x 200 pixels
EGA Enhanced Graphics Adapter 16 Colours - 640 x 350 pixels
VGA Video Graphics Array 256 Colours - 640 x 480 pixels
sVGA Video Graphics Array 256 Colours - 800 x 600 pixels
XGA eXtended Graphics Array - 1024 x 1024 pixels
Other (Video cards now allow for higher pixel densities to enable accurate display on large monitors).
Eg. 1280 x 1280 , and beyond.

Standards

	640 x 480 x 16 colours	Basic VGA setting for Windows. Suitable if you require a clear large font, and output is primarily directed to the printer. Not used a lot today.
	640 x 480 x 256 colours	Pre 1997 (pre Pentium) standard for Multimedia
	800 x 600 x 16 colours	Super VGA (sVGA), suitable if you want more on your screen - eg. if you often work with multiple documents or applications, with output mainly directed at the printer, or to 16 colour hypertext (eg Help complier) Also suitable for a 15" monitor
	800 x 600 x 256 colours (1MB RAM req'd)	Standard for Multimedia on 15"+ monitor
	640 x 480 x 256 colours	Pre 1997 standard for Multimedia. Handles JPG and MPEG files.
	800 x 600 x 16.8 million colours (2MB RAM req'd)	Emerging standard for Multimedia. Handles JPG and MPEG files.
	1024 x 768 x 256 colours (2MB RAM req'd)	XGA - extended graphics from IBM
	1024 x 768 x 16.8 million colours (4MB RAM req'd)

Accelerated Graphics Port (AGP)

vga_agp.gif (5845 bytes)

Intel technology used for video cards only. Optimised for use with Intel Pentium II processors (1998) and above.
There is normally a single AGP slot in the PC's motherboard providing a dedicated high bandwidth connection between the CPU and video card by way of the AGP-enabled chipset.
Developed to solve the bottleneck associated with transporting complex 3D texture maps over the Peripheral Component Interconnect (PCI) bus.
Provides 533MBytes/s to a theoretical 2.1 GBytes/s with the 8x's AGP specification in AGP 3.0 (compared to the bandwidth of the standard 132Mbps PCI bus).

Verton, D (1998, Apr) , Poland, Pat (2001, Oct)

Graphics chips

Intel740
- 2D-3D chip
- AGP2x (Accelerated Graphics Port) support so requires Pentium II
- Performs certain 3D calculations (including texture mapping) pixel by pixel
- Does AGP texturing where detailed textures are stored in teh PCs main memory.

Poland, P. (2001, Oct). AGP made easy. Getting up to speed. NZ PC World # 143, p 107, Intel Inside Graphics Board Makes AGP Zoom (1998, Apr)
[Rev: 31/10/01] 23/12/97 © 1997-2001 V/2-Com (Verhaart), P O Box 8415, Havelock North, New Zealand.