Operating systems miscellaneous

Operating systems miscellaneous

Easy Questions

Operating Systems

Operating systems miscellaneous
  1. A process executes the following code for (i = 0 ; i < n; i ++) for ();
    The total number of child processes created is








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    We know that the total number of processes is 2n but we subtract the main process therefore, total number of children = 2(n – 1) .

    Correct Option: B

    We know that the total number of processes is 2n but we subtract the main process therefore, total number of children = 2(n – 1) .

  1. 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 P2 is blocked state can make transition E while another process P1 is in running state.
    3. The operating system uses pre-emptive scheduling.
    4. The operating system uses non-pre-emptive scheduling. Which of the above statements are true?








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    1. is false. If a process makes a transition D, it would result in another process making transition B, not A. 2. is true. A process can move to ready state when I/O completes irrespective of other process being in running state or not.
    3. is true because there is a transition from running to ready state.
    4. is false as the OS uses preemptive scheduling

    Correct Option: C

    1. is false. If a process makes a transition D, it would result in another process making transition B, not A. 2. is true. A process can move to ready state when I/O completes irrespective of other process being in running state or not.
    3. is true because there is a transition from running to ready state.
    4. is false as the OS uses preemptive scheduling

  1. A multithreaded program P executes with x number of threads and uses y number of locks for ensuring mutual exclusion while operating on shared memory locations. All locks in the program are non-reentrant, i.e, if a thread holds a lock l, then it cannot re-acquire lock l without releasing it. If a thread is unable to acquire a lock, it blocks until the lock becomes available. The minimum value of x and the minimum value of y together for which execution of P can result in a deadlock are :








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    In an multithreaded program P executes with X number of threads and Y number of locks for ensuring mutual exclustion while operating on shared memory location. Now consider each option.
    (a) X = 1, Y = 2.
    If there is one thread and two locks then there is not situation of deadlock.
    (b) X = 2, Y = 1.
    Similarly if there is only 1 lock and 2 thread, then there will be no deadlock situation.
    (c) X = 2, Y = 2
    If there is 2 thread and 2 locks then the Deadlock situation can arise because both threads can holds one lock and can wait for release of another lock, which arises deadlock.
    (d) X = 1, Y = 1
    If there is one thread and one locks, then one thread can hold one lock, then there will be no deadlock situation.
    So, option (c) is correct.

    Correct Option: C

    In an multithreaded program P executes with X number of threads and Y number of locks for ensuring mutual exclustion while operating on shared memory location. Now consider each option.
    (a) X = 1, Y = 2.
    If there is one thread and two locks then there is not situation of deadlock.
    (b) X = 2, Y = 1.
    Similarly if there is only 1 lock and 2 thread, then there will be no deadlock situation.
    (c) X = 2, Y = 2
    If there is 2 thread and 2 locks then the Deadlock situation can arise because both threads can holds one lock and can wait for release of another lock, which arises deadlock.
    (d) X = 1, Y = 1
    If there is one thread and one locks, then one thread can hold one lock, then there will be no deadlock situation.
    So, option (c) is correct.

  1. Which of the following is/are shared by all the threads in a process?
    I. Program counter
    II. Stack
    III. Address space
    IV. Registers








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    The thread is a light weight process and all the threads in a process has share address space but other entities like, stack, PC, registers are not shared and every thread will have its own.
    So, option (b) is correct.

    Correct Option: B

    The thread is a light weight process and all the threads in a process has share address space but other entities like, stack, PC, registers are not shared and every thread will have its own.
    So, option (b) is correct.

  1. The maximum number of processes that can be in Ready state for a computer system with n CPUs is








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    Number of processes which are in running processes will be atmost n as there are n processors. Maximum number of processes that will be in ready state is independent of number of processors.

    Correct Option: D

    Number of processes which are in running processes will be atmost n as there are n processors. Maximum number of processes that will be in ready state is independent of number of processors.