Question

Draw a timeline for each of the following scheduling algorithms. (It may be helpful to first compute a start and finish time for each job.) a. FCFS b. SJN c. SRT d. Round robin (using a time quantum of 5, ignore context switching and natural wait)

Answer 1

Answer:

See explanation below

Explanation:

Previos concepts

First Come First Serve (FCFS) "is an operating system scheduling algorithm that automatically executes queued requests and processes in order of their arrival".

Shortest job next (SJN), or the shortest job first (SJF) or shortest "is a scheduling policy that selects for execution the waiting process with the smallest execution time".

Shortest remaining time (SRF) "is a scheduling method that is a preemptive version of shortest job next scheduling'".

Round robin (RR) is an algorithm where the time parts "are assigned to each process in equal portions and in circular order, handling all processes without priority"

Solution for the problem

Assuming the dataset given on the plot attached.

Part a

For this algorithm the result would be:

Job A   0-6

Job B   6-(6+3) = 6-9

Job C   9-(9+1) = 9-10

Job D   10-(10+4) = 10-14

Part b

For this algorithm the result would be:

Job A   0-6

Job C   6-(6+1) = 6-7

Job B   7-(7+3) = 7-10

Job D   10-(10+4) = 10-14

Part c

For this algorithm the result would be:

Job A   0-1  until 14

Job B   2-(2+3) = 2-5

Job C   3-(3+2) = 3-5

Job D   9-(9+5) = 9-14

Part d

For this algorithm the result would be:

Job A   0-2 , 7-9, 12-14

Job B   2-4, 9-10

Job C   4-(4+1) = 4-5

Job D   5-7, 10-12