Computer Science Study Materials for Competitive Exams

Sample Questions, Previous Year Solved Papers, Study Materials For Competitive Examinations Like UGC NET, SET And GATE Computer Science.

Tuesday, 29 May 2018

UGC NET Computer Science Solved Questions December 2013 Paper 3 - Part 8

71.       Simplest way of deadlock recovery is
(A) Roll back
(B) Preempt resource
(C) Lock one of the processes
(D) Kill one of the processes
Answer: D
Explanation:
Recovery through killing processes
– crudest but simplest way to break a deadlock
– kill one of the processes in the deadlock cycle
– the other processes get its resources
– choose process that can be rerun from the beginning. Kind of an extreme form of
“rollback”.
72.       The directory structure used in Unix file system is called
(A) Hierarchical directory
(B) Tree structured directory
(C) Directed acyclic graph
(D) Graph structured directory
Answer: C
73.       Which statement is not true about process 0 in the Unix operating system?
(A) Process 0 is called init process.
(B) Process 0 is not created by fork system call.
(C) After forking process 1, process 0 becomes swapper process.
(D) Process 0 is a special process created when system boots.
Answer: A
Explanation:
Process 0 is a special process that is created when the system boots. Process 1 (init process) is the child of Process 0. All the other processes in UNIX has Process 1 as
ancestor. All new processes are created under Process 1 (init process).
74.       Which of the following commands would return process_id of sleep command?
(A) Sleep 1 and echo $?
(B) Sleep 1 and echo $#
(C) Sleep 1 and echo $x
(D) Sleep 1 and echo $!
Answer: D
75.       Possible thread states in Windows 2000 operating system include:
(A) Ready, running and waiting
(B) Ready, standby, running, waiting, transition and terminated.
(C) Ready, running, waiting, transition and terminated
(D) Standby, running, transition and terminated.
Answer: B
Explanation:
The six possible thread states are ready, standby, running, waiting, transition, and terminated. Ready means waiting to run. The highest-priority ready thread is moved to the standby state, which means that it will be the next thread to run. In a multiprocessor system, one thread is kept in the standby state for each processor. A thread is running when it is executing on a processor. It will run until it is preempted by a higher-priority thread, until it terminates, until its time quantum ends, or until it calls a blocking system call, such as for I/O. A thread is in the waiting state when it is waiting for a signal such as an I/O completion. A new thread is in the transition state while it is waiting for the resources necessary for execution. A thread enters the terminated state when it finishes execution.


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