This preview shows page 1. Sign up to view the full content.
Unformatted text preview: executes a portion of its ﬂow and then is preempted (temporarily suspended) while other processes take their turns. To 8.2. PROCESSES
Process A Process B Process C 399 Time Figure 8.10: Logical control ﬂows. Processes provide each program with the illusion that it has exclusive use of the processor. Each vertical bar represents a portion of the logical control ﬂow for a process. a program running in the context of one of these processes, it appears to have exclusive use of the processor. The only evidence to the contrary is that if we were to precisely measure the elapsed time of each instruction (see Chapter 9), we would notice that the CPU appears to periodically stall between the execution of some of the instructions in our program. However, each time the processor stalls, it subsequently resumes execution of our program without any change to the contents of the program’s memory locations or registers. In general, each logical ﬂow is independent of any other ﬂow in the sense that the logical ﬂows associated with different processes...
View Full Document
- Spring '10
- The American