Chapter III processor scheduling exercise

Catalog

One . Single topic selection （ common 10 topic ,83 branch ）

1. ( Single topic selection ) The time slice rotation scheduling algorithm is to （ ）.

2. ( Single topic selection ) In a multiprocessing system with a single processor , When a process takes up the processor and how long it takes is determined by （ ） Decisive .

3. ( Single topic selection )（ ） advantageous to CPU Busy homework , It's not good for /0 Busy homework .

4. ( Single topic selection ) The following guidelines for selecting process scheduling algorithms are incorrect （ ）.

5. ( Single topic selection ) Equipped with 4 Two assignments arrive at the same time , The execution time of each job is 2h, They run as a single channel on a single processor , The average turnaround time is （ ）.

6. ( Single topic selection ) Now there are three assignments arriving at the same time J1, J2 and J3, Their execution times are T1, T2, T3, And

. The system operates in a single channel mode and adopts short job first scheduling algorithm , Then the average turnaround time is （ ）.

7. ( Single topic selection ) There are three assignments , The running time is 2h, 5h, 3h, Suppose they arrive at the same time , And run in a single channel on the same processor , Then the execution order with the smallest average turnaround time is （ ）.

8. ( Single topic selection ) One assignment 8:00 Arrival system , Estimated run time is 1h. if 10:00 Start executing the job , The response ratio is （ ）.

9. ( Single topic selection ) The process scheduling algorithm adopts fixed time slice rotation scheduling algorithm , When the time slice is too large , The time slice rotation algorithm will be transformed into （ ） Scheduling algorithm .

10. ( Single topic selection ) Yes 5 Batch jobs A、B、C、D、E Arrive almost at the same time , The estimated running time is 10、6、2、4、8, Its priority （ It's set externally ） Respectively 3、5、2、1、4, here 5 Is the highest priority . In the following scheduling algorithm , The average turnaround time is 14 Yes. （ ） Scheduling algorithm .

Two . Completion （ common 2 topic ,17 branch ）

11. ( Completion ) Yes 5 Batch jobs A To E All have arrived at the computing center , The running time is respectively 2 、4 、6 、8 and 10 minute ： Their respective priorities are 1、2、3、4、5 、 here 5 For the most advanced . about 1) Time slice rotation algorithm 、2） Priority scheduling algorithm 、3） Short job first algorithm 、4） First come first serve scheduling algorithm （ In order of arrival C 、D 、B 、E 、A) , Ignore the process switching time , Calculate the average turnover time . Yes （ Time slice rotation algorithm each job gets the same 2 Minutes long time slice ; Yes 2） To 4） The algorithm uses single channel operation , Until the end .）. The calculation results shall be filled in the corresponding brackets .（1） The average job turnover time of the time slice rotation algorithm is （）.（2） The average job turnover time of the priority scheduling algorithm is （）.（3） The average turnaround time of the short job first algorithm is （）.（4） The average job turnover time of the first come first service scheduling algorithm is （）.

12. ( Completion ) The main memory of a multiprogramming system for users is 100K , Tape drive 2 platform , The printer 1 platform . Adopt dynamic partition memory management （ The program's move position in memory is not supported ）, In a static way （ Once the equipment is allocated , Return after the process is used ） Assign peripherals , Ignore user jobs I/O Time . The existing job sequence is as follows ：

Job scheduling uses FCFS Strategy , Allocate the low address area of main memory first , Each job in main memory is divided equally CPU Time ． Now ：( l ） The order in which jobs are scheduled ？( 2 ） The time when all jobs end ？( 3 ） What is the average turnaround time of the job ？( 4 ） What is the maximum operation turnaround time ？ Please fill in the answers in the corresponding brackets .（1） The order in which jobs are scheduled is （）, Fill in the job number , Separated by a space .（2） The time when all jobs end is （）, Fill in the form when ： branch .（3） The average turnaround time of the job is （） minute .（4） The maximum turnaround time is （） minute .

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One . Single topic selection （ common 10 topic ,83 branch ）

1. ( Single topic selection ) The time slice rotation scheduling algorithm is to （ ）.

• A. Multiple terminals can get timely response from the system

• B. Make the system efficient

• C. Higher priority processes get timely response

• D. need CPU The process with the least time is the first to do

My answer : C right key : A

0 branch

2. ( Single topic selection ) In a multiprocessing system with a single processor , When a process takes up the processor and how long it takes is determined by （ ） Decisive .

• A. The corresponding code length of the process

• B. The total time the process needs to run

• C. Process characteristics and process scheduling strategy

• D. What function does the process complete

My answer : C right key : C

8.3 branch

3. ( Single topic selection )（ ） advantageous to CPU Busy homework , It's not good for /0 Busy homework .

• A. Time slice rotation scheduling algorithm

• B. First come first serve scheduling algorithm

• C. Short assignments （ process ） Priority algorithm

• D. Priority scheduling algorithm

My answer : B right key : B

8.3 branch

4. ( Single topic selection ) The following guidelines for selecting process scheduling algorithms are incorrect （ ）.

• A. Respond to interactive user requests as soon as possible

• B. Maximize processor utilization

• C. Improve the system throughput as much as possible

• D. Appropriately increase the waiting time of the process ready queue

My answer : D right key : D

8.3 branch

5. ( Single topic selection ) Equipped with 4 Two assignments arrive at the same time , The execution time of each job is 2h, They run as a single channel on a single processor , The average turnaround time is （ ）.

• A. 1h

• B. 5h

• C. 2.5h

• D. 8h

My answer : B right key : B

8.3 branch

6. ( Single topic selection ) Now there are three assignments arriving at the same time J1, J2 and J3, Their execution times are T1, T2, T3, And

. The system operates in a single channel mode and adopts short job first scheduling algorithm , Then the average turnaround time is （ ）.

• A. T1+T2+T3

• B. （3xTl+2xT2+T3）/3

• C. （T1+T2+T3）/3

• D. （T1+2xT2+3xT3/3

My answer : B right key : B

8.3 branch

Analysis of the answer ：

7. ( Single topic selection ) There are three assignments , The running time is 2h, 5h, 3h, Suppose they arrive at the same time , And run in a single channel on the same processor , Then the execution order with the smallest average turnaround time is （ ）.

• A. J1,J2,J3

• B. J3,J2,J1

• C. J2,J1,J3

• D. J1,J3,J2

My answer : D right key : D

8.3 branch

8. ( Single topic selection ) One assignment 8:00 Arrival system , Estimated run time is 1h. if 10:00 Start executing the job , The response ratio is （ ）.

• A. 2

• B. 1

• C. 3

• D. 0.5

My answer : C right key : C

8.3 branch

9. ( Single topic selection ) The process scheduling algorithm adopts fixed time slice rotation scheduling algorithm , When the time slice is too large , The time slice rotation algorithm will be transformed into （ ） Scheduling algorithm .

• A. High response ratio first

• B. First come, first served

• C. Short process priority

• D. None of the above options is right

My answer : B right key : B

8.3 branch

10. ( Single topic selection ) Yes 5 Batch jobs A、B、C、D、E Arrive almost at the same time , The estimated running time is 10、6、2、4、8, Its priority （ It's set externally ） Respectively 3、5、2、1、4, here 5 Is the highest priority . In the following scheduling algorithm , The average turnaround time is 14 Yes. （ ） Scheduling algorithm .

• A. Time slice rotation （ The time slice is 1）

• B. Priority scheduling

• C. First come, first served （ In order 10、6、2、4、8）

• D. Short job preferred

My answer : D right key : D

8.3 branch

Analysis of the answer ：

Two . Completion （ common 2 topic ,17 branch ）

11. ( Completion ) Yes 5 Batch jobs A To E All have arrived at the computing center , The running time is respectively 2 、4 、6 、8 and 10 minute ： Their respective priorities are 1、2、3、4、5 、 here 5 For the most advanced . about 1) Time slice rotation algorithm 、2） Priority scheduling algorithm 、3） Short job first algorithm 、4） First come first serve scheduling algorithm （ In order of arrival C 、D 、B 、E 、A) , Ignore the process switching time , Calculate the average turnover time . Yes （ Time slice rotation algorithm each job gets the same 2 Minutes long time slice ; Yes 2） To 4） The algorithm uses single channel operation , Until the end .）. The calculation results shall be filled in the corresponding brackets .（1） The average job turnover time of the time slice rotation algorithm is （）.（2） The average job turnover time of the priority scheduling algorithm is （）.（3） The average turnaround time of the short job first algorithm is （）.（4） The average job turnover time of the first come first service scheduling algorithm is （）.

• My answer ：**8.3 branch

  (1) 18

  (2) 22

  (3) 14

  (4) 19.2

• right key ：

  (1) 18

  (2) 22

  (3) 14

  (4) 19.2

Analysis of the answer ：

answer ：( l ) FCFS Scheduling algorithm

( 2 ） Priority scheduling algorithm

( 3 ） Time slice rotation

in turn ABCDEBCDECDEDEE Rotation execution .

( 4 ) SJF Scheduling algorithm

12. ( Completion ) The main memory of a multiprogramming system for users is 100K , Tape drive 2 platform , The printer 1 platform . Adopt dynamic partition memory management （ The program's move position in memory is not supported ）, In a static way （ Once the equipment is allocated , Return after the process is used ） Assign peripherals , Ignore user jobs I/O Time . The existing job sequence is as follows ：

Job scheduling uses FCFS Strategy , Allocate the low address area of main memory first , Each job in main memory is divided equally CPU Time ． Now ：( l ） The order in which jobs are scheduled ？( 2 ） The time when all jobs end ？( 3 ） What is the average turnaround time of the job ？( 4 ） What is the maximum operation turnaround time ？ Please fill in the answers in the corresponding brackets .（1） The order in which jobs are scheduled is （）, Fill in the job number , Separated by a space .（2） The time when all jobs end is （）, Fill in the form when ： branch .（3） The average turnaround time of the job is （） minute .（4） The maximum turnaround time is （） minute .

• My answer ：**8.7 branch

  (1) 1 3 4 2 5

  (2) 9:30

  (3) 44

  (4) 55

• right key ：

  (1) 1 3 4 2 5

  (2) 9：30

  (3) 44

  (4) 55