Identify the circumstances under which pre-emptive CPU scheduling is used: (a) A process switches from Running state to Ready state (b) A process switches from Waiting state to Ready state (c) A process completes its execution (d) A process switches from Ready to Waiting state Choose the correct option:
(a) and (b) only
A Running-to-Ready transition occurs when a process is preempted. A Waiting-to-Ready transition can trigger preemption if the newly ready process should run instead. Termination releases the CPU without preemption, and Ready-to-Waiting is not a standard direct process-state transition. Thus (a) and (b) are correct.
Important Questions from Process
- _________ and _________ are used in conjunction for making a complete process subroutine.
A computer system has 7 tape drives. There are ‘n’ processes competing for them. Each process may need 2 tape drives. What is the maximum value of ‘n’ for which the system is guaranteed to be deadlock free?
Assuming that the system call fork () never fails, consider the following C programs P1 and P2 executed on a UNIX / Linux system:
/*P1*/
Int main() {
fork ():
fork () ;
fork () ;
Printf(“Happy\n”);
}
/*P2*/
Int main() {
fork ();
Printf(“Happy\n”);
fork ()
Printf(“Happy\n”);
fork () ;
Printf(“Happy\n”);
}
Statement I: P1 displays "Happy" 8 times.
Statement II: P2 displays "Happy" 12 times.
In the light of the above statements, choose the correct answer from the options given below
Match List I with List II
List I
List II
System calls
Description
A.
fork()
I.
Sends a signal from one process to another process
B.
exec()
II.
Indicates termination of the current process
C.
kill()
III.
Loads the specified program in the memory
D.
exit()
IV.
Creates a child process
Choose the correct answer from the options given below :
________ system call creates new process in Unix.
