Question

Currently a company that designs Web sites has five customers in its backlog. The time since the order​ arrived, processing​ time, and promised due dates are given in the following table. The customers are ready to be scheduled​ today, which is the start of day

190.

                                                                                               

Customer	Time Since Order Arrived ​(days ago)	Processing Time​ (days)	Due Date ​(days from ​now)
Upper AA	88	12	50
Upper BB	66	10	66
Upper CC	33	24	58
Upper DD	22	32	100
Upper EE	10	20	26

a. Develop separate schedules by using the FCFS and EDD rules. Compare the schedules on the basis of average flow time and average days past due.

Using the FCFS​ (first come, first​ served) decision rule for sequencing the​ customers, the order​ is:

Sequence	1	2	3	4	5
Customer	E	A	B	C	D

Using the EDD​ (earliest due​ date) decision rule for sequencing the​ customers, the order is​ (to resolve a​ tie, use the order in which the jobs were​ received):

Sequence	1	2	3	4	5
Customer	E	A	C	B	D

The average flow time and average days past due for each option​ are: ​(Enter your responses rounded to one decimal​ place.)

Rule	Average Flow Time	Average Days Past Due
EDD
FCFS

Answer 1

FCFC means First come first serve. As per FCFS rule, the job will get priority based on the arrival of the job in the system. The job with the earliest arrival will get first priority.

Flow time is the cumulative processing time of the job completed.

Job completion day is a flow time (considerin Day 190 as a Day 1)

Days Past due date = Max (0, Job Completion Day - Due Day)

Average Flow time = Total of Flow time / 5

Average Days past due = Total of Days past due/5

Comparison: