Download BBA IInd SEMESTER EXAMINATION 2008-09

MCA II (Second) Semester Examination 2014-15
Course Code:MCA206
Paper ID: 0872406
Operating System
Time: 3 Hours
Max. Marks: 70
Note: Attempt six questions in all. Q. No. 1 is compulsory.
1.
a)
b)
c)
d)
e)
f)
g)
h)
2. a)
b)
3.
Answer any five of the following (limit your answer to 50
words).
(4x5=20)
What are the functions of an operating system? Explain.
When do page-faults occur? Describe the actions taken by the
operating system when a page-fault occurs.
What is Directory Structure? Discuss its relevance.
What is Banker’s algorithm? How is it relevant? Explain.
What is Page Size? What is the criterion to decide a Page
Size? Explain.
Differentiate between Paging and Segmentation.
What are Semaphores? How do these help? Explain.
Differentiate between internal fragmentation and external
fragmentation? How can you minimize the same? Explain.
What is an operating system? What are the desirable features
of a good operating system? How an operating system is
viewed as an extended machine? Illustrate.
(5)
What is meant by On-line, Real-time and Multi-tasked
systems? Illustrate through suitable examples. How the
designing of Real-Time operating systems is viewed
differently from the other operating system?
(5)
For batch jobs A through E, arrive at a Computer System at
almost the same time. They have estimated running times of
10, 6, 2, 4, and 8 minutes. Their (externally determined)
priorities are 3, 5, 2, 1, and 4, respectively, with 5 being the
highest priority. For each of the following scheduling
algorithms, determine the mean process turnaround time.
Ignore process switching overhead.
i)
Round robin
ii)
Priority scheduling
iii)
First-come, First-served (run in order 10,6, 2, 4, 8)
iv)
Shortest job first
For (i) assume that the system is multi-programmed, and to
each job gets share of the CPU. For (ii) through (iv) assume
that only one job at a time runs, until finishes. All jobs are
completely CPU bound.
(10)
4. a) What do you mean by process management? What are
different process management functions of the operating
system? Explain the life-cycle of a process.
(5)
b) What is a process scheduler? How preemptive and nonpreemptive scheduling differ from each other? State why
strict non-preemptive scheduling is unlikely to be used in a
Computer System.
(5)
5. a) What is meant by synchronization? How the synchronization
tools help in offering a correct solution for 'Readers and
Writers' problem? Explain.
(5)
b) What is mutual exclusion? What are the necessary and
sufficient conditions for deadlock?
(5)
6. a) Describe Belady’s anomaly, and provide an example that
illustrates anomalous behavior of FIFO.
(4)
b) What is a Swapping System? Consider a swapping system in
which memory of the following hole sizes in memory order:
10K, 4K, 20K, 18K, 7K, 9K, 12K, and 15K. Which hole is
taken for successive requests of:
i) 12K
ii) 10K
iii) 9K
for First-Fit ? Repeat the same for Best-Fit, Worst-Fit, and
Next-Fit.
(6)
7. a) What is the cause of thrashing? How does the system detect
thrashing? Once it detects thrashing, what can the system do
to eliminate this problem?
(5)
b) What are Page Replacement algorithms? Compare these
algorithms indicating their benefits.
(5)
8.
What do you understand by disk scheduling? What are
various disk scheduling algorithms? Compare these
algorithms highlighting their suitability.
(10)