Specifications

894
Chapter 15 Video Hardware
How can you tell whether the monitor is really off or in standby mode? Look at the power LCD
on the front of the monitor. A monitor that’s in standby mode usually has a blinking green or
solid amber LCD in place of the solid green LCD displayed when it’s running in normal mode.
Because monitors in standby mode still consume some power, they should be shut off at the
end of the computing day.
If the monitor will not go into standby when the PC isn’t sending signals to it, make sure the
monitor is properly defined in Windows’s Display Properties sheet. In addition, the Energy Star
check box should be selected for any monitor that supports power management, unless the moni-
tor should be left on at all times (such as when used in a retail kiosk or self-standing display).
■ Make sure the monitor has adequate ventilation along the sides, rear, and top. Because monitors use
passive cooling, a lack of adequate airflow caused by piling keyboards, folders, books, or other
office debris on top of the monitor will cause it to overheat and considerably shorten its life. If
you’re looking at a monitor with a partly melted grille on the top of the case, you’re looking at
a victim of poor cooling. If you need to use a monitor in an area with poor airflow, use an LCD
panel instead of a CRT because LCDs run much cooler than CRTs.
■ The monitor screen and case should be kept clean. Turn off the power, spray a cleaner such as
Endust for Electronics onto a soft cloth (never directly onto the monitor!), and wipe the screen
and the case gently.
■ If your CRT monitor has a degaussing button or feature, use it periodically to remove stray magnetic sig-
nals. Keep in mind that CRTs have powerful magnets around the picture tube, so keep magnetic
media away from them.
Video Display Adapters
A video adapter provides the interface between your computer and your monitor and transmits the
signals that appear as images on the display. Throughout the history of the PC, there have been a suc-
cession of standards for video display characteristics that represent a steady increase in screen resolu-
tion and color depth. The following list of standards can serve as an abbreviated history of PC
video-display technology:
MDA (Monochrome Display Adapter)
HGC (Hercules Graphics Card)
CGA (Color Graphics Adapter)
EGA (Enhanced Graphics Adapter)
VGA (Video Graphics Array)
SVGA (Super VGA)
XGA (Extended Graphics Array)
IBM pioneered most of these standards, but other manufacturers of compatible PCs adopted them as
well. Today, IBM is no longer the industry leader it once was (and hasn’t been for some time), and
many of these standards are obsolete. Those that aren’t obsolete seldom are referred to by these
names anymore. The sole exception to this is VGA, which is a term that is still used to refer to a base-
line graphics display capability supported by virtually every video adapter on the market today.
When you shop for a video adapter today, you are more likely to see specific references to the screen
resolutions and color depths that the device supports than a list of standards such as VGA, SVGA,
XGA, and UVGA. However, reading about these standards gives you a good idea of how video-display
technology developed over the years and prepares you for any close encounters you might have with
legacy equipment from the dark ages.
Today’s VGA and later video adapters can also display most older color graphics software written for CGA,
EGA, and most other obsolete graphics standards. This enables you to use older graphics software (such as
games and educational programs) on your current system. Although not a concern for most users, some
older programs wrote directly to hardware registers that are no longer found on current video cards.
16 1738 ch15 7/30/04 10:31 AM Page 894