For problems 1 and 2, a computer has the following four processes that have arrived in the ready queue in the sequence shown below. NOTES: (1) Time slicing is not used, therefore, there are no mandatory time outs. (2) I/O operations only occur one time during the process execution.
Process 1 has a run time of 30 seconds, a priority of 2, and it will require 15 seconds of I/O after an initial 10 seconds of execution.
Process 2 has a run time of 20 seconds, a priority of 1, and it will require 10 seconds of I/O after an initial 5 seconds of execution.
Process 3 has a run time of 15 seconds and a priority of 2.
Process 4 has a run time of 25 seconds and a priority of 1, and it will require 15 seconds of I/O after an initial 10 seconds of execution
1. If the Round Robin Scheduling algorithm is used, which process completes first? Why? At what time does it complete?
2. If the Round Robin with Priority Queues Scheduling algorithm is used, which process completes second? Why? At what time does it complete?
3. The manual for a popular operating system points out that the number of concurrent users on the system can be increased if the users are sharing programs, such as editors, mail readers, or compilers. What characteristics of virtual storage make this possible?
4. Using a variable-partitioned multiprogramming memory, which of the four holes shown below will be used to satisfy a 45 KB program requirement under the conditions of:
|
0-45 KB
|
45-105 KB
|
105-145 KB
|
145-185 KB
|
185-260 KB
|
260-330 KB
|
330-350 KB
|
350-405 KB
|
405-470 KB
|
|
occupied
|
Hole A
|
occupied
|
Hole B
|
occupied
|
Hole C
|
occupied
|
Hole D
|
occupied
|
Question 1: If the shortest job first scheduling algorithm is used, at what times will each of the four processes complete its execution?
Question 2: If the non preemptive priority queue scheduling algorithm is used, at what times will each of the four processes be complete?
Question 3: If the shortest remaining time scheduling algorithm is used, at what times will each of the four processes be complete?
Question 4: If the round robin with priority queues scheduling algorithm is used with a timeout after 15 seconds of execution, at what times will each of the four processes complete its execution?
Question 5: Using a variable-partitioned multiprogramming memory, which of the three holes shown below will be used to satisfy a 50 Kb program requirement under the conditions of:
______ First-fit
______ Best-fit
______ Worst-fit
