- Joined
- Apr 9, 2004
- Location
- My Room-USA
I start out by appologizing DEEPLY for the length of this but i would like to let people know something about what some of us take for granted: our monitors. 
How the Monitor Works
Inside the monitor is a glass tube known as the Cathode Ray Tube (CRT). Within this CRT beams are passed back and forth from top to bottom and from left to right. The dots together, when illuminated create an image.
On color monitors, each dot carries one of three colors, red, green, or blue. The dots are called picture elements or pixels. An electron beam behind the pixels designate the pixels intensity.
Inside the monitor is a controller board that performs the communication with the adapter card. Two technologies are used for this: shadow mask, and aperture grill.
Shadow Mask: A metal screen with thousands of very small holes. The mask is placed so that the holes are directly in line with the dots of each pixel. The shadow mask absorbs unwanted electrons and prevents the phosphor material between the pixels from being illuminated, which leaves a black border around each pixel.
Aperture Grill: Very thin vertical wires let more electrons through that the shadow mask, creating a deeper color display. Horizontal wires hold the vertical wires in the place to keep the verticals from vibrating.
Video Adapter Card Standards
Monochrome Display Adapter (MDA): Does just what its name says, displays mostly text on a monochrome monitor. This digital adapter is still used for servers, process control, and monitoring systems when the display contains only text and a color display is not needed. Resolution is not an issue on MDA monitors. It works just like a dot matrix printer, using illuminated dots to form letters on each line of the display. A variation of the MDA that integrates fraphics is the Hercules based Monochrome Graphics Adapter (MGA).
Color Graphics Adapter (CGA): This digital adapter was the first color adapter. It's capable of displaying four colors. CGA monitors supported 320 x 200 (four colors) or 640 x 200 Itwo colors). In this case, as well as those that follow, as the number of colors increases, typically the resolution decreases. This trade off must take place so that the video RAM is not exceeded.
Enhanced Graphics Adapter (EGA): This digital adapter supports 16 colors at a resolution of 640 x 350.
Video Graphics Array (VGA): VGA is the standard for video adapters on Windows as well as several other OSs. The VGA standard supports 640 x 480 with 16 colors or lower resolutions with 256 colors.
Super Video Graphics Array (SVGA): Most of the video standards that followed VGA and support resolutions and color depths higher than those of the VGA standard are grouped under teh SVGA standard. The SVGA standard was developed by the VESA, which is made up of monitor and graphics card manufacturers and other companies interested in video standards. SVGA video cards support several resolutions including 800 x 600; 1,024 x 768; 1,280 x 1,024; 1,600 x 1,200; and higher end up to 4 billion colors, although 16.7 million colors is more commonly used as the standard.
Display Quality Terms
Resolution: The number of pixels available to produce an image.
Resolution is important for two reasons, it determines the quality of the produced image, and it determines how much video RAM will be used.
Dot Pitch: The distance between two pixels. The closer together the pixels are, the better the image quality.
Color Depth: Number of colors that a video card or monitor can display.
Color depth also determines the number of colors each pixel can display.
Aspect Ratio: The ration of horizontal pixels to vertical.
Aspect Ratio determines the types of shapes a monitor can produce.
Video RAMs
Dynamic Random Access Memory (DRAM): The same DRAM used on early PCs.
Extended Data Output DRAM (EDO DRAM): Provides a higher bandwidth and handles read/write cycles better than standard DRAM.
Video RAM (VRAM): VRAM, not to be confused with the generic "VRAM," is a special type of DRAM that doesn't need to be refreshed quite as often. VRAM is dual-ported meaning that it has two access portals, and the process and RAMDAC (RAM digital to analog converter) can both be accessing it at the same time.
Windows RAM (WRAM): Called Windows Accelerator Card RAM by some, WRAM is dual ported memory that runs a little faster than VRAM.
Synchronous DRAM (SDRAM): SDRAM is EDO DRAM that it is synchronized to the video card's processor and chipset. SDRAM is single ported (one door) memory that is very common on video cards.
Double Data Rate SDRAM (DDR SDRAM): DDR SDRAM has twice the data transfer speed of standard SDRAM.
Synchronous Graphics RAM (SGRAM): An improvement on standard SDRAM adds features such as block writes and write per bit that support faster graphics performance. Block write is used to copy the contents of a color register into memory in a single block cycle. Write per bit allows a single bit of data block to be changed without the need to rewrite the entire data block. SGRAM, which is single ported memory, is found only on video cards with chipsets that support it.
Double Data Rate SGRAM (DDR SGRAM): DDR does for SGRAM excatly what it did for SDRAM, it doubles its data transfer rate.
Direct Rambus DRAM (RDRAM): A general purpose memory type that is used for the PC's main meory (as well as video cards) that runs about 20 times faster than conventional DRAM. RDRAM includes bus mastering and dedicated channels between memory devices. Bus mastering allows the video card to take control of the PC's system bus and transfer data into and out of system RAM. This improves the performance of some video operations that use primary RAM for certain calculations, such as 3-D acceleration.
Unified Memory Architecture (UMA): Many lower-cost systems intended for home use integrate graphics support and the video system into the motherboard. UMA is so named because it uses system RAM for video memory. This technology almost always produces inferior graphics performance.
Most of my information and definitions was taken from A+ certification books I have. Once again i appologize for the length. Maybe it can become a sticky. Thanks for reading.
How the Monitor Works
Inside the monitor is a glass tube known as the Cathode Ray Tube (CRT). Within this CRT beams are passed back and forth from top to bottom and from left to right. The dots together, when illuminated create an image.
On color monitors, each dot carries one of three colors, red, green, or blue. The dots are called picture elements or pixels. An electron beam behind the pixels designate the pixels intensity.
Inside the monitor is a controller board that performs the communication with the adapter card. Two technologies are used for this: shadow mask, and aperture grill.
Shadow Mask: A metal screen with thousands of very small holes. The mask is placed so that the holes are directly in line with the dots of each pixel. The shadow mask absorbs unwanted electrons and prevents the phosphor material between the pixels from being illuminated, which leaves a black border around each pixel.
Aperture Grill: Very thin vertical wires let more electrons through that the shadow mask, creating a deeper color display. Horizontal wires hold the vertical wires in the place to keep the verticals from vibrating.
Video Adapter Card Standards
Monochrome Display Adapter (MDA): Does just what its name says, displays mostly text on a monochrome monitor. This digital adapter is still used for servers, process control, and monitoring systems when the display contains only text and a color display is not needed. Resolution is not an issue on MDA monitors. It works just like a dot matrix printer, using illuminated dots to form letters on each line of the display. A variation of the MDA that integrates fraphics is the Hercules based Monochrome Graphics Adapter (MGA).
Color Graphics Adapter (CGA): This digital adapter was the first color adapter. It's capable of displaying four colors. CGA monitors supported 320 x 200 (four colors) or 640 x 200 Itwo colors). In this case, as well as those that follow, as the number of colors increases, typically the resolution decreases. This trade off must take place so that the video RAM is not exceeded.
Enhanced Graphics Adapter (EGA): This digital adapter supports 16 colors at a resolution of 640 x 350.
Video Graphics Array (VGA): VGA is the standard for video adapters on Windows as well as several other OSs. The VGA standard supports 640 x 480 with 16 colors or lower resolutions with 256 colors.
Super Video Graphics Array (SVGA): Most of the video standards that followed VGA and support resolutions and color depths higher than those of the VGA standard are grouped under teh SVGA standard. The SVGA standard was developed by the VESA, which is made up of monitor and graphics card manufacturers and other companies interested in video standards. SVGA video cards support several resolutions including 800 x 600; 1,024 x 768; 1,280 x 1,024; 1,600 x 1,200; and higher end up to 4 billion colors, although 16.7 million colors is more commonly used as the standard.
Display Quality Terms
Resolution: The number of pixels available to produce an image.
Resolution is important for two reasons, it determines the quality of the produced image, and it determines how much video RAM will be used.
Dot Pitch: The distance between two pixels. The closer together the pixels are, the better the image quality.
Color Depth: Number of colors that a video card or monitor can display.
Color depth also determines the number of colors each pixel can display.
Aspect Ratio: The ration of horizontal pixels to vertical.
Aspect Ratio determines the types of shapes a monitor can produce.
Video RAMs
Dynamic Random Access Memory (DRAM): The same DRAM used on early PCs.
Extended Data Output DRAM (EDO DRAM): Provides a higher bandwidth and handles read/write cycles better than standard DRAM.
Video RAM (VRAM): VRAM, not to be confused with the generic "VRAM," is a special type of DRAM that doesn't need to be refreshed quite as often. VRAM is dual-ported meaning that it has two access portals, and the process and RAMDAC (RAM digital to analog converter) can both be accessing it at the same time.
Windows RAM (WRAM): Called Windows Accelerator Card RAM by some, WRAM is dual ported memory that runs a little faster than VRAM.
Synchronous DRAM (SDRAM): SDRAM is EDO DRAM that it is synchronized to the video card's processor and chipset. SDRAM is single ported (one door) memory that is very common on video cards.
Double Data Rate SDRAM (DDR SDRAM): DDR SDRAM has twice the data transfer speed of standard SDRAM.
Synchronous Graphics RAM (SGRAM): An improvement on standard SDRAM adds features such as block writes and write per bit that support faster graphics performance. Block write is used to copy the contents of a color register into memory in a single block cycle. Write per bit allows a single bit of data block to be changed without the need to rewrite the entire data block. SGRAM, which is single ported memory, is found only on video cards with chipsets that support it.
Double Data Rate SGRAM (DDR SGRAM): DDR does for SGRAM excatly what it did for SDRAM, it doubles its data transfer rate.
Direct Rambus DRAM (RDRAM): A general purpose memory type that is used for the PC's main meory (as well as video cards) that runs about 20 times faster than conventional DRAM. RDRAM includes bus mastering and dedicated channels between memory devices. Bus mastering allows the video card to take control of the PC's system bus and transfer data into and out of system RAM. This improves the performance of some video operations that use primary RAM for certain calculations, such as 3-D acceleration.
Unified Memory Architecture (UMA): Many lower-cost systems intended for home use integrate graphics support and the video system into the motherboard. UMA is so named because it uses system RAM for video memory. This technology almost always produces inferior graphics performance.
Most of my information and definitions was taken from A+ certification books I have. Once again i appologize for the length. Maybe it can become a sticky. Thanks for reading.
