arihant gate tutor 2016

Question

which one is correst #round robin scheduling is essentially the preemptive version of 1) FIFO 2) shortest job first 3) shortest remaining time first 4) longest time first

Comments

Round Robin scheduling is essentially the preemptive version of FIFO

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Bt answer is longest time first is given in arihant tutor book

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that shows how un relaible these books are

Answer 1

Answer 1 ) FIFO

Round robin and FIFO are related like this

FIFO: First task in, First task out...

Means that as you insert task to the queue, they are in the order processed (the time a task will run is INFINITE, or the task itself can give up CPU time).

Every task is defaultly inserted in FIFO queue.

+ Order of completion is preserved

-  long running processes can stall the system.

- less context switch overhead.

Round-Robin:

The same as FIFO, but the time is NOT INFINITE:

time slices are assigned to each process in equal portions and in circular order.

+ Use round robin if it is desirable to allow long running processes to execute while not interfering with shorter ones

+ starvation free

- Order of completion is not guaranteed.

- Round Robin can suffer if there are many processes in the system, since it will take longer for each process to complete since the round trip is longer.

- No prioritization occurs, and waiting time is high. So deadlines are rarely met in a pure Round Robin system.

This link is kinda helpful https://en.wikipedia.org/wiki/Scheduling_%28computing%29#First_in.2C_first_out