the following six jobs are to be scheduled on a single machine:\njob 1 2 3 4 5 6\nprocessing time (min.) 100…

the following six jobs are to be scheduled on a single machine:\njob 1 2 3 4 5 6\nprocessing time (min.) 100 130 230 120 170 60\n\na. suppose the jobs are processed in fcfs numerical order. compute the makespan, flow time for each job, and overall average flow time. round your answers to the nearest whole number.\njob flow time (min)\n1\n2\n3\n4\n5\n6\nmakespan: minutes\naverage flow time: minutes\n\nb. in what order would the jobs be processed using the spt rule?\nthe spt sequence is select - select - select - select - select - select.\ncompute the average flow time after each job is completed. round your answer to the nearest whole number.\naverage flow time: minutes\ncompare this answer with your answer to part a.\nthe select minimizes flow time and gets the most work done in the least amount of time.

the following six jobs are to be scheduled on a single machine:\njob 1 2 3 4 5 6\nprocessing time (min.) 100 130 230 120 170 60\n\na. suppose the jobs are processed in fcfs numerical order. compute the makespan, flow time for each job, and overall average flow time. round your answers to the nearest whole number.\njob flow time (min)\n1\n2\n3\n4\n5\n6\nmakespan: minutes\naverage flow time: minutes\n\nb. in what order would the jobs be processed using the spt rule?\nthe spt sequence is select - select - select - select - select - select.\ncompute the average flow time after each job is completed. round your answer to the nearest whole number.\naverage flow time: minutes\ncompare this answer with your answer to part a.\nthe select minimizes flow time and gets the most work done in the least amount of time.

Answer

Explanation:

Step1: Calculate flow - time and makespan for FCFS

In First - Come, First - Served (FCFS) order, the flow time of a job is the cumulative processing time of all previous jobs plus its own processing time. For job 1: Flow time = 100 For job 2: Flow time = 100 + 130=230 For job 3: Flow time = 100 + 130+230 = 460 For job 4: Flow time = 100 + 130+230 + 120=580 For job 5: Flow time = 100 + 130+230 + 120+170 = 750 For job 6: Flow time = 100 + 130+230 + 120+170+60 = 810 Makespan is the total time to complete all jobs, which is the sum of all processing times: 100 + 130+230 + 120+170+60=810 Average flow time = $\frac{100 + 230+460+580+750+810}{6}=\frac{2930}{6}\approx488$

Step2: Determine SPT order and average flow time

Shortest Processing Time (SPT) order arranges jobs in ascending order of processing time. The SPT order is 6 - 1 - 4 - 2 - 5 - 3 For job 6: Flow time = 60 For job 1: Flow time = 60 + 100 = 160 For job 4: Flow time = 60+100 + 120 = 280 For job 2: Flow time = 60+100 + 120+130 = 410 For job 5: Flow time = 60+100 + 120+130+170 = 580 For job 3: Flow time = 60+100 + 120+130+170+230 = 810 Average flow time = $\frac{60 + 160+280+410+580+810}{6}=\frac{2300}{6}\approx383$

Answer:

Job Flow Time (min):

  1. 100
  2. 230
  3. 460
  4. 580
  5. 750
  6. 810 Makespan: 810 minutes Average flow time (FCFS): 488 minutes SPT sequence: 6 - 1 - 4 - 2 - 5 - 3 Average flow time (SPT): 383 minutes The SPT rule minimizes flow time and gets the most work done in the least amount of time.