A directory of Objective Type Questions covering all the Computer Science subjects. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews.

61. Which of the following disk scheduling policies results in minimum amount of head movement.
a. FCS
b. Circular scan
c. Elevator
d. None of the above
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Answer: (b).Circular scan

62. Consider a hard disk with 16 recording surfaces (0-15) having 16384 cylinders (0-16383) and each cylinder contains 64 sectors (0-63). Data storage capacity in each sector is 512 bytes. Data are organized cylinder-wise and the addressing format is (cylinder no., surface no., sector no.) . A file of size 42797 KB is stored in the disk and the starting disk location of the file is (1200, 9, 40). What is the cylinder number of the last sector of the file, if it is stored in a contiguous manner?
a. 1281
b. 1282
c. 1283
d. 1284
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Answer: (d).1284

63. A file system with 300 GByte disk uses a file descriptor with 8 direct block addresses, 1 indirect block address and 1 doubly indirect block address. The size of each disk block is 128 Bytes and the size of each disk block address is 8 Bytes. The maximum possible file size in this file system is
a. 3 Kbytes
b. 35 Kbytes
c. 280 Bytes
d. Dependent on the size of the disk
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Answer: (b).35 Kbytes

64. A computer handles several interrupt sources of which the following are relevant for this question.

. Interrupt from CPU temperature sensor (raises interrupt if
CPU temperature is too high)
. Interrupt from Mouse(raises interrupt if the mouse is moved
or a button is pressed)
. Interrupt from Keyboard(raises interrupt when a key is
pressed or released)
. Interrupt from Hard Disk(raises interrupt when a disk
read is completed)

Which one of these will be handled at the HIGHEST priority?
a. Interrupt from Hard Disk
b. Interrupt from Mouse
c. Interrupt from Keyboard
d. Interrupt from CPU temperature sensor
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Answer: (d).Interrupt from CPU temperature sensor

65. An application loads 100 libraries at start-up. Loading each library requires exactly one disk access. The seek time of the disk to a random location is given as 10 ms. Rotational speed of disk is 6000 rpm. If all 100 libraries are loaded from random locations on the disk, how long does it take to load all libraries? (The time to transfer data from the disk block once the head has been positioned at the start of the block may be neglected)
a. 0.50 s
b. 1.50 s
c. 1.25 s
d. 1.00 s
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Answer: (b).1.50 s

66. A CPU generally handles an interrupt by executing an interrupt service routine
a. As soon as an interrupt is raised
b. By checking the interrupt register at the end of fetch cycle
c. By checking the interrupt register after finishing the execution of the current instruction
d. By checking the interrupt register at fixed time intervals
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Answer: (c).By checking the interrupt register after finishing the execution of the current instruction

67. A hard disk has 63 sectors per track, 10 platters each with 2 recording surfaces and 1000 cylinders. The address of a sector is given as a triple (c, h, s), where c is the cylinder number, h is the surface number and s is the sector number. Thus, the 0th sector is addressed as (0, 0, 0), the 1st sector as (0, 0, 1), and so on The address (400,16,29) corresponds to sector number:
a. 505035
b. 505036
c. 505037
d. 505038
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Answer: (c).505037

68. The data blocks of a very large file in the Unix file system are allocated using
a. contiguous allocation
b. linked allocation
c. indexed allocation
d. an extension of indexed allocation
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Answer: (d).an extension of indexed allocation

69. For a magnetic disk with concentric circular tracks, the seek latency is not linearly proportional to the seek distance due to
a. non-uniform distribution of requests
b. arm starting and stopping inertia
c. higher capacity of tracks on the periphery of the platter
d. use of unfair arm scheduling policies
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Answer: (b).arm starting and stopping inertia

70. Which of the following statements about synchronous and asynchronous I/O is NOT true?
a. An ISR is invoked on completion of I/O in synchronous I/O but not in asynchronous I/O
b. In both synchronous and asynchronous I/O, an ISR (Interrupt Service Routine) is invoked after completion of the I/O
c. A process making a synchronous I/O call waits until I/O is complete, but a process making an asynchronous I/O call does not wait for completion of the I/O
d. In the case of synchronous I/O, the process waiting for the completion of I/O is woken up by the ISR that is invoked after the completion of I/O
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Answer: (a).An ISR is invoked on completion of I/O in synchronous I/O but not in asynchronous I/O

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