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+18 votes
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In the following process state transition diagram for a uniprocessor system, assume that there are always some processes in the ready state:

    

Now consider the following statements:

  1. If a process makes a transition $D$, it would result in another process making transition $A$ immediately.
  2. A process $P_2$ in blocked state can make transition E while another process $P_1$ is in running state.
  3. The OS uses preemptive scheduling.
  4. The OS uses non-preemptive scheduling.

Which of the above statements are TRUE?

  1. I and II
  2. I and III
  3. II and III
  4. II and IV
asked in Operating System by Veteran (59.5k points)
edited by | 1.7k views

3 Answers

+32 votes
Best answer
  1. If a process makes a transition $D$, it would result in another process making transition $A$ immediately. - This is false. It is not said anywhere that one process terminates, another process immediately come into Ready state. It depends on availability of process to run & Long term Scheduler.
  2. A process $P2$ in blocked state can make transition $E$ while another process $P2$ is in running state. - This is correct. There is no dependency between running process & Process getting out of blocked state.
  3. The OS uses preemptive scheduling. :- This is true because we got transition $C$ from Running to Ready.
  4. The OS uses non-preemptive scheduling.Well as previous statement is true, this becomes false.

So answer is (C) II and III .

answered by Boss (42.6k points)
edited by
0
If CPU uses preemptive scheduling then only option 2 is possible. But nothing is given about that in the question.?
+1
say in case of transition A it is written as Transition B then the statement  "If a process makes a transition D, it would result in another process making transition B immediately"  would be correct ?
0
since the long term scheduler controls the degree of multiprogramming,if one process terminates ,it should create a new process. correct me if i am wrong?
+16 votes

Answer is C :

The reason why option 1 may be false :If the process terminate ; then the Short time scheduler will bring immediately process from ready to run (not from new to ready ) . The process of bringing a process from new to ready is responsibility is job of Long Term Scheduler (which is called not so frequently as compared to Short Time Scheduler . Hence we named it Long Time Scheduler . the decision taken by it stays for a long time )

answered by Active (1.2k points)
+5 votes
It is C.

The option I is not necessarily true.
answered by Boss (19.7k points)
Answer:

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