We've seen that memory can be broadly divided into two categories: memory that the system can change, and that which the system cannot change. RAM and ROM are the beginning concepts for understanding memory. The BIOS is where the motherboard remembers the most basic instructions about hardware, but the CMOS is where basic system settings are stored. BIOS and CMOS are different, in that CMOS requires a small amount of electricity to maintain its settings.
BIOS and CMOS can be changed, but not without some effort. Make sure you know the acronyms associated with these chips and the ways in which they can be updated. Additionally, you should have a comfortable sense of understanding about the following points, having to do with memory:
The central processing unit, the memory controller, cache memory, and the system clock
How timing affects performance, and the difference between asynchronous and synchronous data transfers
The North bridge and South bridge architecture, and how the front side bus stands between the CPU and the North bridge (see Chapter 2).
Be sure that you have a good understanding of how data can be stored in memory cells, using ranges and range addresses. You should be able to differentiate between FPM and EDO memory, and dynamic (asynchronous) versus synchronous RAM. You won't be asked to calculate or remember burst cycles, but you should understand the concept of moving data as opposed to waiting cycles. A critical concept is the relationship between clocks (oscillators) and data transfers. If you can't remember how the motherboard uses timing cycles, go back and skim Chapter 2.