Operating Systems Question Paper
Operating Systems
Course:Bachelor Of Computer Science (It Telecommunication)
Institution: Kabarak University question papers
Exam Year:2010
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KABARAK UNIVERSITY
UNIVERSITY EXAMINATIONS
2010/2011 ACADEMIC YEAR
FOR THE DEGREE OF BACHELOR OF COMPUTER
SCIENCE
COURSE CODE: COMP 220
COURSE TITLE: OPERATING SYSTEMS
STREAM: Y2S2
DAY: TUESDAY
TIME: 2.00 – 4.00 P.M.
DATE: 14/12/2010
INSTRUCTIONS:
Note: - Part-A is compulsory, have 30 marks and from Part-B, You can attempt any two
questions. Each question has 20 marks.
PLEASE TURNOVER
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PART-A
QUESTION 1
a) Discuss the inconveniences that a user might face while interacting with a computer system,
which is without an operating system. (4Marks )
b) What are the benefits of multiprogramming? Explain any six. (5Marks)
c) Definitions for the following terms:
(i) Program
(ii) Process
(iii) Multiprogramming (3Marks)
d) What is the difference between true and concurrent server? (2Marks)
e) What are the benefits of parallel systems? Explain any three. (6Marks )
f) (i) What are the differences between segmentation and paging?
(ii) Explain an advantages and disadvantages of each. (4Marks)
g) Shown below is the workload for 5 jobs arriving at time zero in the order given below:-
Job Burst
1 10
2 29
3 3
4 7
5 12
Now considering SJF and round robin (RR) [with quantum = 10] algorithms for this set of jobs,
find out which algorithm would give the minimum average time. (6 Marks)
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PART B
QUESTION TWO
a) Differentiates between batch processing system and real time processing system.
(6Marks)
b) Differentiate between real time system and timesharing system. (4Marks )
c) Consider a system with a set of processes P1, P2, P3 and P4. Let their arrival times and CPU
burst times mentioned as below:-
Process Arrival time CPU Burst
time
P1 0 3
P2 1 6
P3 5 4
P4 6 2
Calculate all for FCFS, SJF and RR scheduling algorithms.
(i) Average turnaround time (3Marks )
(ii) Average waiting time. (3Marks )
(iii)Average throughput. (2Marks )
d) What is in a thread control block? (2Marks)
QUESTION 3
a) What is scheduling? What criteria affect the performance of various schedulers? Explain any
four.
(7Marks)
b) What is time slicing? How the time slicing duration affects the overall working of the
system? (4Mark )
c) Explain the following allocation algorithms with advantages and disadvantages.
i. First fit.
ii. Best fit
iii. Next fit. (6Marks)
d) How external fragmentation can be avoided. Explain with an example. (3Marks)
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QUESTION FOUR
a) Explain any three access modes for operation on a file. (3Marks)
b) (i) What do understand by file attributes? (2Marks)
(ii)Explain any three categories of file attributes? (3Marks)
c) (i) Explain SRT scheduling with example. (2Marks)
(ii) Give advantages and disadvantages of SRT (2Marks)
e) What are the four different objectives which must be considered in the design of scheduling
discipline? Explain. (4Marks)
f) What factors can lead to the degradation of the performance of round robin (RR) scheduling?
(4Marks)
QUESTION FIVE
a) What is meant by disk scheduling? Explain why disk scheduling is necessary. (4Marks )
b) consider a disk queue with request of I/O to block on cylinder
98, 183, 37, 122, 14, 124, 65, 67
If the disk head is initially at cylinder 53, then calculate total number of head movements using
following algorithms:
i. SCAN
ii. LOOK (6Marks )
c) (i) What is a deadlock situation. (2Marks)
(ii) Explain any four necessary conditions for a deadlock to occur. (4Marks)
d) How can we avoid deadlock situation? Justify your answer. (4Marks)
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