Correct Answer - Option 3 : 3
Answer: 3
Concept:
Earliest Due Date (EDD): Sequence of the job is based on ascending order of Due date/Due time.
Processing time: The time spent by a job on machine.
Due date: Expected completion time of a job.
Flow time: Time spend by a job on shop floor. Cumulative addition of Processing time.
Make span: Time interval between starting of 1st job & coming out of last job in all machine.
Earliness/Tardiness: Time difference between Flow time and Due date time.
-
Earliness: When time difference is negative i.e. Job comes out before due date.
-
Tardiness: When time difference is positive i.e. Job comes out after due date.
Calculation:
Job
|
Processing Time
|
Flow Time
|
Due date
|
Tardiness
|
1
|
4
|
4
|
6
|
0
|
2
|
7
|
11
|
9
|
2
|
4
|
8
|
19
|
17
|
2
|
3
|
2
|
21
|
19
|
2
|
Job 2,3,4 got delayed.
∴ no. of job delayed is 3.
Important Points:
Method
|
Definition
|
First Come First Serve (FCFS)
|
Jobs are arranged as per they arrived
|
Shortest Processing Time (SPT)
|
Jobs are arranged as per the ascending order of Processing Time.
|
Earliest Due Date (EDD)
|
Jobs are arranged as per the ascending order of Due date.
|
Critical Ratio (CR)
|
\(C.R = \frac{{Due\;date}}{{Procesisng\;Time}}\)
Jobs are arranged as per the ascending order of Critical Ratio.
|