Computers as Components, 2nd Edition

310 CHAPTER 6 Processes and Operating Systems

■ A process continues execution until it completes or it is preempted by a higher-priority

process.

Let’s define a simple system with three processes as seen below.

Process Priority Execution time

P1 1 10

P2 2 30

P3 3 20

In addition to describing the properties of the processes in general, we need to know the

environmental setup. We assume that P2 is ready to run when the system is started, P1 is

released at time 15, and P3 is released at time 18.

Once we know the process properties and the environment,we can use the pri-

orities to determine which process is running throughout the complete execution

of the