CertiGuide to A+ (A+ 4 Real)  9  Chapter 8: Motherboards       9  What is a Bus?

I/O Bus 1 Expansion Buses

In general, cache is a small memory space that contains either data that was recently accessed by the computer and may soon be needed again or data that, due to programming is “perceived” by the computer as likely to be frequently accessed. So why is this data kept in cache and not accessed from where it resides on the hard drive or alternately kept in RAM? Moreover, where is “cache” anyway?

Cache is a small memory space associated with the computer’s CPU. The whole point of faster and faster processors is that they will perform at higher and higher capacities. One method if speeding up the process is to store data the CPU processes often very near the CPU in it’s own on board memory so that when called for, it is accessed almost instantly.

Of course, in a larger context, the term cache can refer to any type of small memory space where data is temporarily and briefly stored waiting some form of processing. For example, some network switches that have the ability to prioritize types of network traffic will store different categories of traffic in caches at each switch port until the data can be sent onto the network.

I/O Bus 1 Expansion Buses