Two Views of Today’s Computer

 The modern computer has become faster and more powerful but the basic architecture of a computing machine has essentially stayed the same for many years. Today we can take two equivalent views of the machine: The hardware view and the software view. The hard-ware view, not surprisingly, focuses on the machine and does allow for the fact that the software has something to do with its reason to exist. From 50,000 feet, our computer looks like Figure 1.2.In this course, we’ll focus primarily on the CPU and memory systems, with some consideration of the software that drives this hardware. We’ll touch briefly on I/O, since a computer isn’t much good without it.The software developer’s view is roughly equivalent, but the perspective does change somewhat. Figure 1.3 shows the computer from the software designer’s point of view. Note that the view of the system shown in this figure is somewhat problematic because it isn’t always clear that the user interface communicates directly with the application program. In many cases, the user interface first communicates with the operating system. However, let’s look at this diagram somewhat loosely and consider it to be the flow of information, rather than the flow of control.