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.

131. Four jobs J1, J2, J3 and J4 are waiting to be run. Their expected run times are 9, 6, 3 and 5 respectively. In order to minimize average response time, the jobs should be run in the order:
a. J1 J2 J3 J4
b. J4 J3 J2 J1
c. J3 J4 J1 J2
d. J3 J4 J2 J1
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Answer: (d).J3 J4 J2 J1

132. Suppose it takes 100 ns to access page table and 20 ns to access associative memory. If the average access time is 28 ns, the corresponding hit rate is:
a. 100 percent
b. 90 percent
c. 80 percent
d. 70 percent
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Answer: (b).90 percent

133. N processes are waiting for I/O. A process spends a fraction p of its time in I/O wait state. The CPU utilization is given by:
a. 1 - p^-N
b. 1 - p^N
c. p^N
d. p^-N
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Answer: (b).1 - p^N

134. If holes are half as large as processes, the fraction of memory wasted in holes is:
a. 2/3
b. 1/2
c. 1/3
d. 1/5
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Answer: (d).1/5

135. An example of a non pre-emptive scheduling algorithm is:
a. Round Robin
b. Priority Scheduling
c. Shortest job first
d. 2 level scheduling
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Answer: (c).Shortest job first

136. An example of distributed OS is:
a. Amoeba
b. UNIX
c. MS-DOS
d. MULTICS
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Answer: (a).Amoeba

137. In which of the following, ready to execute processes must be present in RAM?
a. multiprocessing
b. multiprogramming
c. multitasking
d. all of the above
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Answer: (d).all of the above

138. If the executing program size is greater than the existing RAM of a computer, it is still possible to execute the program if the OS supports:
a. multitasking
b. virtual memory
c. paging system
d. none of the above
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Answer: (b).virtual memory

139. Files that are related to input/output and are used to model serial I/O devices such as terminals, printers and networks are called :
a. regular files
b. character special files
c. directories
d. block special files
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Answer: (d).block special files

140. An example of a possible file attribute is:
a. minimum size
b. permanent flag
c. archive flag
d. EBCDIC flag
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Answer: (c).archive flag