job name | arrival time | service time | start time | finish time | turnaround time | waiting time | response time |
---|---|---|---|---|---|---|---|

A | 0 | 10 | 0 | 10 | 10 | 0 | 1.0 |

B | 1 | 29 | 10 | 39 | 38 | 9 | 1.3 |

C | 2 | 3 | 39 | 42 | 40 | 37 | 13.3 |

D | 3 | 7 | 42 | 49 | 46 | 39 | 6.6 |

E | 4 | 12 | 49 | 61 | 57 | 45 | 4.8 |

mean | 38 | 26 | 5.4 |

job name | arrival time | service time | start time | finish time | turnaround time | waiting time | response time |
---|---|---|---|---|---|---|---|

A | 0 | 10 | 0 | 10 | 10 | 0 | 1.0 |

B | 1 | 29 | 32 | 61 | 60 | 31 | 2.1 |

C | 2 | 3 | 10 | 13 | 11 | 8 | 3.7 |

D | 3 | 7 | 13 | 20 | 17 | 10 | 2.4 |

E | 4 | 12 | 20 | 32 | 28 | 16 | 2.3 |

mean | 25 | 13 | 2.3 |

job name | arrival time | service time | start time | finish time | turnaround time | waiting time | response time |
---|---|---|---|---|---|---|---|

A | 0 | 10 | 0 | 2 | pre-empted by C | ||

12 | 20 | 20 | 10 | 2.0 | |||

B | 1 | 29 | 32 | 61 | 60 | 31 | 2.1 |

C | 2 | 3 | 2 | 5 | 3 | 0 | 1.0 |

D | 3 | 7 | 5 | 12 | 9 | 2 | 1.3 |

E | 4 | 12 | 20 | 32 | 28 | 16 | 2.3 |

mean | 24 | 12 | 1.7 |

job name | arrival time | service time | start time | finish time | turnaround time | waiting time | response time |
---|---|---|---|---|---|---|---|

A | 0 | 10 | 0 | 10 | 10 | 0 | 1.0 |

B | 1 | 29 | 32 | 61 | 60 | 31 | 2.1 |

C | 2 | 3 | 10 | 13 | 11 | 8 | 3.7 |

D | 3 | 7 | 13 | 20 | 17 | 10 | 2.4 |

E | 4 | 12 | 20 | 32 | 28 | 16 | 2.3 |

mean | 25 | 13 | 2.3 |

job name | arrival time | service time | start time | finish time | turnaround time | waiting time | response time |
---|---|---|---|---|---|---|---|

A | 0 | 10 | 0 | 5 | end of quantum; B starts | ||

5 | 23 | 28 | 28 | 18 | 2.8 | ||

B | 1 | 29 | 5 | 10 | end of quantum; C starts | ||

24 | 28 | 33 | end of quantum; D starts | ||||

19 | 40 | 45 | end of quantum; E starts | ||||

14 | 47 | 61 | 60 | 31 | 2.1 | ||

C | 2 | 3 | 10 | 13 | 11 | 8 | 3.7 |

D | 3 | 7 | 13 | 18 | end of quantum; E starts | ||

2 | 33 | 35 | 32 | 25 | 4.6 | ||

E | 4 | 12 | 18 | 23 | end of quantum; A starts | ||

7 | 35 | 40 | end of quantum; B starts | ||||

2 | 45 | 47 | 43 | 31 | 3.5 | ||

mean | 35 | 23 | 3.3 |

time | job running | ready queue (at end of interval) |
new queue (at end of interval) |
---|---|---|---|

0-1 | A | A(2) | B(0) |

1-2 | A | A(4) | B(3), C(0) |

2-3 | A | B(6), A(6) | C(3), D(0) |

3-4 | B | A(8), B(8) | C(6), D(3), E(0) |

4-5 | A | B(10),A(10) | C(9), D(6), E(3) |

5-6 | B | A(12), C(12), B(12) | D(9), E(6) |

6-7 | A | C(14), B(14), A(14) | D(12), E(9) |

7-8 | C | B(16), A(16), C(16) | D(15), E(12) |

8-9 | B | A(18), C(18), D(18), B(18) | E(15) |

9-10 | A | C(20), D(20), B(20), A(20) | E(18) |

10-11 | C | D(22), B(22), A(22), C(22) | E(21) |

11-12 | D | B(24), A(24), C(24), E(24), D(24) | |

... round robin from here on ... |

job name | arrival time | service time | start time | finish time | turnaround time | waiting time | response time |
---|---|---|---|---|---|---|---|

A | 0 | 10 | ... | ... | 27 | 17 | 2.7 |

B | 1 | 29 | ... | ... | 60 | 31 | 2.1 |

C | 2 | 3 | ... | ... | 15 | 12 | 5.0 |

D | 3 | 7 | ... | ... | 33 | 26 | 4.7 |

E | 4 | 12 | ... | ... | 44 | 32 | 3.7 |

mean | 35.8 | 23.6 | 3.6 |

- processes at level 1 are scheduled round robin; the relevant quantum is 2, and when a quantum expires the job is moved to level 2.
- processes at level 2 are scheduled round robin; the quantum is 4, and processes are allowed 2 quanta before being moved to level 3.
- processes at level 3 are serviced first come first serve.
The jobs A, B, C, D, and E have been augmented by F, a 1-second job arriving at
time 13, and G, an 11-second job arriving at time 50. These are to demonstrate
that quanta are usually
**not**interrupted.

In what follows, the number in parentheses in the comment field is the remaining service time for the job.time level 1 level 2 level 3 comments 0 A -- -- A(10) arrives, runs 1 AB -- -- B(29) arrives, A continues quantum 2 BC A -- C(3) arrives, A's quantum expires (8), moves to level 2, B runs 3 BCD A -- D(7) arrives, B continues quantum 4 CDE AB -- E(12) arrives, B's quantum expires (27), moves down, C runs 6 DE ABC -- C's quantum expires (1), moves down, D runs 8 E ABCD -- D's quantum expires (5), moves down, E runs 10 -- ABCDE -- E's quantum expires (10), moves down, A runs from level 2 (level 1 is empty) 13 F ABCDE -- F(1) arrives, A's quantum continues 14 F ABCDE -- A's quantum expires (4), F runs (at level 1) 15 -- ABCDE -- F finishes, B runs from level 2 (level 1 is empty) 19 -- ABCDE -- B's quantum expires (23), C runs 20 -- ABDE -- C finishes, D runs 24 -- ABDE -- D's quantum expires (1), E runs 28 -- ABDE -- E's quantum expires (6), A runs 32 -- BDE -- A finishes, B runs 36 -- DE B B's quantum expires (19), moves down, D runs 37 -- E B D finishes, E runs 41 -- -- BE E's quantum expires (2), moves down, B runs from level 3 (since there is nothing in higher levels) 50 G -- BE G arrives(11), B continues to run 60 G -- E B finishes, G runs (since it is in the highest level) 62 -- G G's quantum expires (9), moves down, G runs from level 2 66 -- G E G's quantum expires (5), G runs 70 -- -- EG G's quantum expires (1), moves down, E runs 72 -- -- G E finishes, G runs 73 -- -- -- G finishes job name arrival time service time start time finish time turnaround time waiting time response time A 0 10 0 2 *preempted by B*8 10 14 *preempted by F*4 28 32 32 22 3.2 B 1 29 2 4 *preempted by C*27 15 19 *preempted by C*23 32 36 *preempted by D*19 41 60 59 30 2.0 C 2 3 4 6 *preempted by D*1 19 20 18 15 6.0 D 3 7 6 8 *preempted by E*5 20 24 *preempted by E*1 36 37 34 27 4.9 E 4 12 8 10 *preempted by A*10 24 28 *preempted by A*6 37 41 *preempted by B*2 70 72 68 56 5.7 F 13 1 14 15 2 1 2.0 G 50 11 60 70 *preempted by E*1 72 73 23 12 2.1 mean 33.7 23.3 3.7

Send email to cs150@csif.cs.ucdavis.edu.Department of Computer Science

University of California at Davis

Davis, CA 95616-8562

Page last modified on 5/13/99