3.1. Understanding Video Adapters

A video adapter (video card) — the interface between the monitor and the computer — is responsible for converting the digital data from the computer into analog information. The data is converted to an analog signal before being delivered to a monitor because monitors use analog data to create the image.

Because display functions are very time- and memory-consuming, most video adapters these days have their own processing chip and memory to alleviate the processing workload from the CPU. Today's video adapters are typically PCIe or AGP cards, but you might run into some older systems that require a PCI video card because these systems don't have an AGP or a PCIe slot. For more information on PCIe and AGP, check out Book II, Chapter 1.

The following outlines the basic role of what the video adapter does when it comes to displaying data on the computer screen:

  1. Data is sent to the video card via the expansion bus that the video card resides in.

  2. The video chipset on the video card writes the data to memory located on the card.

  3. After being stored in memory, the data is passed to the digital-to-analog converter (DAC), where it is converted from digital signals to analog signals that the monitor can understand.

  4. The data is passed to the monitor, which then displays the data on the screen.

The video adapter is identifiable by its unique 15-pin female connector, comprising 5 pins in 3 rows. On most systems today, the port on the video card is typically blue ...

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