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Consider three CPU intensive processes, which require 10, 20, 30 units and arrive at times 0,2,6 respectively. How many context switches are needed if shortest remaining time first is implemented? Context switch at 0 is included but context switch at end is ignored

Consider three CPU intensive processes, which require 10, 20, 30 units and arrive at times 0,2,6 respectively. How many context switches are needed if shortest remaining time first is implemented? Context switch at 0 is included but context switch at end is ignored Correct Answer 3

Scheduling Algorithm:

shortest remaining time first

Gantt chart:

P1

P2

P3

0               10               30               60

Process table:

Process Id

Arrival Time (AT)

Burst Time (BT)

Completion Time (CT)

1

0

10

10

2

2

20

30

3

6

30

60

 

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Number of context switches = 2

Since initial is included 

Therefore total context switches = 1 + 2 = 3

Important Points:

Context switch at 0 is included but context switch at end is ignored

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