Memory Systems: Cache, DRAM, Disk

The first question I ask myself when something doesn't seem to be beautiful is why do I think it's not beautiful. And very shortly you discover that there is no reason.
John Cage
DRAM is the "computer memory" that you order through the mail or purchase at the store. It is what you put more of into your computer as an upgrade to improve the computer's performance. It appears in most computers in the form shown in Figure 7.1 the ubiquitous memory module, a small computer board (a printed circuit board, or PCB) that has a handful of chips attached to it. The eight black rectangles on the pictured module are the DRAM chips: plastic packages, each of which encloses a DRAM die (a very thin, fragile piece of silicon).
Figure 7.2 illustrates DRAM's place in a typical PC. An individual DRAM device typically connects indirectly to a CPU (i.e., a microprocessor) through a...