Neither systems architects nor computer architecture researchers have paid as much attention to I/O as they have to processors. The rationale for this lack of attention is completely unclear to us, since I/O is a key part of a system, being both a driver for system performance and an opportunity for value add—unlike processors, where the economies of scale predominate. As we will see in this chapter, I/O is an area where some interesting work has been done.
In the previous chapter, we provided a generic server model with the purpose of identifying the various interconnects of interest, mentioning the interconnects between processor, memory and I/O.
An I/O system comprises a number of elements, illustrated in Figure 2.1.
Figure 2.1. The ...