Q. Consider the following processes with time slice of 4 milliseconds (I/O requests are ignored):

Process               A         B         C         D
Arrival time        0          1          2          3
CPU cycle         8          4          9          5

The average turn around time of these processes will be

View solution

Q. A job has four pages A, B, C, D and the main memory has two page frames only. The job needs to process its pages in following order:

ABACABDBACD

Assuming that a page interrupt occurs when a new page is brought in the main memory, irrespective of whether the page is swapped out or not. The number of page interrupts in FIFO and LRU page replacement algorithms are

View solution

Q. Suppose S and Q are two semaphores initialized to 1. P1 and P2 are two processes which are sharing resources.

P1 has statements                 P2 has statements
wait(S) ;                                     wait(Q) ;
wait(Q) ;                                     wait(S) ;
critical section1;                       critical section 2;
signal(S) ;                                 signal(Q) ;
signal(Q) ;                                 signal(S) ;

Their execution may sometimes lead to an undesirable situation called

View solution

Q. An operating system using banker’s algorithm for deadlock avoidance has ten dedicated devices (of same type) and has three processes P1, P2 and P3 with maximum resource requirements of 4, 5 and 8 respectively. There are two states of allocation of devices as follows:

State 1   Processes                 P1       P2       P3
Devices allocated    2          3          4

State 2   Processes                 P1       P2       P3
Devices allocated    0          2          4

Which of the following is correct?

View solution

Q. Let the time taken to switch between user mode and kernel mode of execution be T1 while time taken to switch between two user processes be T2. Which of the following is correct?

View solution

Q. Working set model is used in memory management to implement the concept of

View solution

Q. A thread is usually defined as a light weight process because an Operating System (OS) maintains smaller data structure for a thread than for a process. In relation to this, which of the following statement is correct?

View solution

Q. The versions of windows operating system like windows XP and window Vista uses following file system:

View solution

Q. Pre-emptive scheduling is the strategy of temporarily suspending a gunning process

View solution

Q. In round robin CPU scheduling as time quantum is increased the average turn around time

View solution

Q. Consider the following page trace : 4,3, 2, 1, 4, 3, 5, 4, 3, 2, 1, 5. Percentage of page fault that would occur if FIFO page replacement algorithm is used with number of frames for the JOB m=4 will be

View solution

Q. Which of the following is scheme to deal with deadlock ?

View solution

Q. A computer system supports 32 bit virtual address as well as 32 bit physical addresses. Since the virtual address space is of same size as that of physical address space, if we want to get rid of virtual memory, which one of the following is true ?

View solution

Q. If an instruction takes ‘i’ microseconds and a page fault takes an additional ‘j’ microseconds. The effective instruction time, if on the average a page fault occurs every k instructions, is

View solution

Q. Consider the methods used by processes P1 and P2 for accessing their critical sections. The initial values of shared Boolean variables S1 and S2 are randomly assigned,

P1                                         P2
while (S1 = = S2);             while (S1 = = S2);
critical section                  critical section
S1 = S2;                              S1 = S2;

Which one of the following statements describes the properties achieved ?

View solution

Q. On a disk with 1000 cylinders (0 to 999) find the number of tracks, the disk arm must move to satisfy all the requests in the disk queue. Assume the last request service was at track 345 and the head is moving toward track 0. The queue in FIFO order contains requests for the following tracks :
123, 874, 692, 475, 105, 376
(Assume SCAN algorithm)

View solution

Q. Dijkestra banking algorithm in an operating system, solves the problem of

View solution

Q. The multiuser operating system, 20 requests are made to use a particular resource per hour, on an average the probability that no request are made in 45 minutes is

View solution

Q. The maximum amount of information that is available in one portion of the disk access arm for a removal disk pack (without further movement of the arm with multiple heads)

View solution

Q. A file organization component VSAM file is

View solution