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Reading Assignment and Discussion Topics
Computer Science 111

for class on Tuesday March 24, 1998

Please read Sections 6.1 and 6.2 of the Schneider and Gersting text, and be prepared to discuss the following:

As I type this, my PC appears to be doing a lot of things simultaneously. Of course it's responding to the keys I type, but it's also playing a CD, keeping track of the time, running Netscape, and holding up another half-dozen windows in which various things are happening. But at the level of machine-language programs, there is really only one thing going on: the computer can only execute one instruction at a time. The operating system creates the illusion that many programs are running in parallel.

Suppose that a bunch of programs and their data are in various separate regions of the computer's memory. How could you make it seem that that the programs were running simultaneously? Consider that

• some of the programs may run for a very very long time if left alone,
• and some of the programs (like the one that tracks the position of the mouse) need to respond to external events.