CertiGuide to A+ (A+ 4 Real)  9  Chapter 8: Motherboards

What is POST? 1 Frontside/Backside Bus

In this case, we are not talking about the Greyhound or School variety of bus but rather an electrical bus. Essentially, an electrical bus is any network of conducting pathways that allow electrical impulses to travel along from source to destination. You could think about the wiring in your car or house as an electrical bus. As far as a computer is concerned, a bus is a set of pathways allowing data to travel as electrical impulses (recall that the language of computers is binary or base two counting and either the absence or presence of current represent zeros and ones). Also in the case of a computer, there is more than one bus present.

When we were discussing chipsets earlier in the chapter, different buses were mentioned such as the ISA bus and the PCI bus. These specific types of data pathways have different characteristics of speed and data capacity. Both ISA buses and PCI buses are known as expansion card buses because they allow daughter boards or expansion cards to communicate with the CPU and the rest of the computer. When we discussed chipset architecture, I mentioned that ISA and PCI buses could also communicate with each other. In the case of Hub architecture, a specialized hub allows the two differing buses and their data to interact. We will discuss expansion buses a bit later in the chapter.

What is POST? 1 Frontside/Backside Bus