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Lesson 3 X-related hardware considerations
Objective Factors that influence the installation of XFree86
What are the factors that influence the installation of XFree86?
Before you install XFree86, you must be aware of your system's video hardware.
The video hardware affects how many colors can be displayed, how many pixels the desktop can hold, and how comfortable the X viewing will be.
The installation procedure prompts you for several hardware parameters, including:
  1. Video card chipset
  2. Amount of video memory
  3. RAMDAC
  4. Monitor scan rates

Several X servers exist, each built to take advantage of particular hardware capabilities. Your video card's chipset determines which server is installed.
Chipset: The particular graphics processing system used on a particular video card.

Amount of memory
The video card's chipset is a processor built for the express purpose of displaying information on a monitor. The amount of memory determines the highest displayable resolutions and color depths. For instance, in the installation simulation you saw a reference to a video mode with 32-bit color depth on a screen of 1280x1024 pixels.
High-resolution modes (those above 1280x1024) produce sharper images, but can decrease system performance.
RAMDAC
A video card's RAMDAC converts the digital signal created by the chipset to the analog signal required by the monitor. You will not need this information for configuration, unless you use xf86config with some older cards.
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Scan rates
A monitor's scan rates determine how often pixels are redrawn.
The video card must produce data at a rate compatible with the monitor's scan rates. Consequently, the X server needs to know this information so it can instruct the video card appropriately.
Scan rates: The rate at which horizontal scan lines are drawn on the monitor and the rate at which one entire sweep of the screen is made. These are referred to as the horizontal and vertical scan rates.
Monitor's Capabilities
Knowledge of the monitor's capabilities is absolutely critical.
Specifying incorrect scan rates when configuring X can permanently damage the monitor!
Consult the monitor's user manual or ask the manufacturer if there is any doubt about its capabilities.
The next lesson explains the various methods to obtain video card specifications.
XWindows fundamentals Quiz
Before moving on to the next lesson, click the Quiz link below to check your understanding of what an X server does and how available hardware affects the configuration.
XWindows Fundamentals - Quiz