Round robin with feedback queues

Question

Round Robin Scheduler implemented a version with feedback queues. There are two ready queues in the system. All new processes are placed in the higher priority Ready queue and interrupted processes are placed in the lower priority ready queue. If there are any processes in the higher priority ready queue then first schedule them by RR before scheduling lower priority ready queue processes.

Consider the following processes with the arrival times and burst times.

Process	P1	P2	P3	P4	P5
Arrival Time	0	2	3	5	6
CPU burst time	3	5	2	4	3

What is the average turn around time of all processes in the given system with time quantum of 2 units for the both ready queues?

Answer 1

Average T.AT = 9.8

Comments

can you please tell why in the first higher priority queue we are using FCFS instead of using RR as question says if there are any processes in the higher priority ready queue then first schedule them by RR and no where written anything about FCFS

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It's a Queue, Process which enters first in the ready queue will be executed first because Round - Robin works same as first come first serve but with a time quantum.
When a process is selected and gets executed on CPU a timer starts, when timer stops it raises an interrupt and currently executing process goes back to ready state, but R-R follows only first in first out concept.
btw, is answer correct?

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thanks buddy and yes answer is correct

Answer 2

its simple...ans will be 9.8.take new process each time and give cpu and then place it into q.