Bus Architecture

When configuring the hardware for a new computer, you have to consider the CPU and motherboard, as discussed earlier in this chapter. In addition, you need to decide which expansion cards to install. Expansion cards include sound cards, video adapters, and network interface cards.

The expansion cards fit into expansion slots built into the motherboard. The most common exceptions are special types of computers such as laptop computers. Expansion cards and the slots they fit into can have several different connector types. The connector types are physically different from one another and have varying performance characteristics.

Some reasons why expansion slots are useful are:

• The earliest motherboards didn't have room for all the necessary components.

• The expansion slots add flexibility in the event that you need to replace a failed expansion card without having to buy a complete new motherboard.

• Most motherboards have several types of expansion slots. The older type of expansion slots, described in the next section, are available to support older expansion cards, protecting consumers' original investment in their hardware.

In most modern computers, you insert a new add-in, or expansion, card as follows:

Warning 

Before opening any electronic device, make sure that the power is turned off and that you are grounded. To ground yourself, use a special tool called an electrostatic discharge wrist strap. One end of the wrist strap attaches to you, and the other end clips to the metal case of the computer. Using the strap prevents you from shocking the computer and possibly causing irreversible damage.

1. Turn the power off and disconnect the power cord from the case.

2. Open the case.

3. Make sure that the card that you are trying to install is the proper type for an open expansion slot.

4. Insert the card and fasten it down.

5. Close the case.

6. Turn the power back on.