2 Explain in detail the Hardware required for effective graphics on the computer system?

Answer 1

GRAPHICS HARDWARE TECHNOLOGY

Computers have been getting progressively more inexpensive and it has become household article in these days. In early days the high cost of the hardware for computer graphics remained the stumbling block, which prevented their widespread use. The microelectronics revolution and the subsequent reduction in the price of the digital hardware have completely changed the situation to the extent that it is now realistic to expect that all computers with graphic display hardware capability will be making extensive use of computer graphics. The announcement of the IBM personal computer using 16-bit Intel 8088 microprocessor on August 12, 1981, can be regarded as a historic event, which had a profound effect in the world of computers.

These computers significantly improved the state of display technology in the world of personal computers. The first IBM PC used Intel 8088 microprocessor, which was capable of addressing 1 Mega bytes in the address space and processing 16 bits internally. Two display adapters could reside in the address space: the Monochrome Display Adapter (MDA) and Color Graphics Adapter (CGA). While the MDA could display 25 rows of 80 column text, the CGA could display graphics as well as text. Several graphics modes were made available, including four-color graphics at a low resolution of 320 X 200 pixels and two

medium resolution color graphics at 640 X 200 pixels. Since then, the 720 X 348 resolution of the Hercules Graphics Card (HGC) and 640 X 350 resolution of the Extended Graphics Adapter (EGA) have become common. In 1984, IBM released a Personal Graphics Controller (PGC) with resolution of 640 X 480 and with 256 simultaneous colors selectable from a palette of 4096. The next major change in PC display technology was announced by Apple Company in 1984, in which it has introduced the Macintosh PC. It was the first PC that does not include a text-based display but provided only a graphic display. The application Programs developed for the Macintosh advocated a WYSIWYG (What You See Is What You Get) style of interface. This concept has become a basic requirement in the area of desktop publishing (DTP). Later in 1987, IBM announced different models of their new PC's (models 30, 50, 60 and 80). In these models one of the protected mode screen groups provided a graphics based windowing system. IBM named it as Presentation Manager while Microsoft named it as Window Presentation Manager. Applications that use graphics can be written for the presentation manager and take advantage of the built-in graphics and dialogue box. The IBM PS/2 line of products introduced the following three new video standards l Multi Color graphics Array (MCGA) l Video Graphic Array (VGA) l 8514/A, a high resolution add-on board The PowerPC's from IBM, Apple and other vendors created a new standard for DTP computers. Graphic User Interface (GUI) like a Microsoft Windows 3.x choke a video adapter sitting on an 8-MHz, 16-bit ISA (industry Standard Architecture) expansion bus. ISA bus is now a bottleneck when it is mated with a 100 MHz Pentium processor. Local Bus Technology breaks the bottleneck by getting peripherals like video controllers up to clock speed. This allows the video controller to gain access to the CPU's 32 bit bus running on full clock speed, e.g. on a 33-MHz, 486 local bus PC a video controller could match the 33 MHz clock speed of the processor. Nevertheless, the video performance is enhanced to 15 times as compared with a standard VGA adapter. Two local bus standards are: VL-Bus, a standard proposed by VESA (Video Electronic Standard Association) Committee and PCI (Peripherals Component Interconnect) a brain child of Intel Corp. EISA (Extended Industry Standard Architecture) and MCA (IBM's Micro Channel Architecture) are similarly limited regarding the rate at which peripherals on the expansion bus can operate. A number of devices like LAN cards, Fax/Modem, CD-Rom interfaces, stereo sound Cards, and Multimedia video support are put in expansion slots to add functionality to personal computers. The user find it difficult to handle the complexities of IRQs, DIP switches, jumpers, and drivers. Apple has Plug and Play (PnP) as standard since 1987 to keep users free from configuration problems. PnP as proposed by Microsoft and Intel will make PCs easy to set up and configure, ease the task of installing new hardware and software, and ability to change configurations set up dynamically on a configuration event. Video/Graphic processing can be made faster in two ways: by using graphic co-processor and a graphic Accelerator. The graphic co-processor boosts video performance by assuming tasks normally handled by the CPU. An accelerator takes control of a graphic task otherwise performed by the CPU but it is not programmable. It is a fixed function processor and which carries out specific tasks hard-coded into the chip. The video adapters and monitors use analog signals and could generate 64 values for each of the primary colors RED, GREEN, and BLUE. The result is that these systems can present 256 colors simultaneously on the screen from a palette on 262144 colors. To provide visual interface, additional processing capability is to be provided to the existing CPU. The solution is to provide dedicated graphic processor. This helps in managing the screen faster with an equivalent software algorithm executed on the CPU and certain amount of parallelism can be achieved for completing the graphic command. Several manufacturers of personal computers use a proprietary graphic processor. For example, Intel 82786 is essentially a line drawing processor; Texas Instruments

43010 is a high performance general-purpose processor.