Biju Patnaik University of Technology 2008-3rd Sem M.C.A Operating System - Question Paper
Third Semester Examination - 2008 OPERATING SYSTEM Full Marks 70
Tfme:3 Hours
Answer Question No. 1 which is compulsory and any five from the rest.
The figures in the right-hand margin indicate marks.
1. Answer t,h,e following questions : 2 *10
a) What is a Semaphore ? What are ils uses ?
What isa thread ? Why \s ft used ?
Write four conditions of dead lock occurrence.
Differentiate between a page and a segment
jfeJ Differentiate between internal and external fragmentation
f) Differentiate between a logical file system ancf a physical fife s/stem.
What js the function of following UNIX commands;
vj, cat, psw, pwd,
Jp) Differentiate between a process and a program.
lky$ Differentiate between time-sharing and batch processing operating system.
(j) Write down the functions of operating system,
3CS 3002 2 Contd,
Consider the following set of processes, with Ihe length of the CPU burst time given in milliseconds :
Process Burst Time Priority
p, 10 3 p, i 1
p3 2 3
P< 1 4
Ps 5 2
Assume all processes have arrived at time, t-0( in order, P1P3 P3 Pj( P5t io
IWL
(i) Draw four Gantt charts illustrating fhe execution of these processes using FCFS, SJFr a nof\preemptive priority (a smaller priority number implies avhigher priority), and RR {quantum -1) scheduling.
(ii) What Is 'the turnaround time of each process for each of the scheduling algorithms in part a ?
PCS 3002 3 pj.o.
(Hi) What is the waiting time ol each process for each of the scheduling algorithms in part a?
(Iv) Which of the schedules w part a results m ihe minimal average wailing time over all processes ?
3 Consider the following snapshot of a system;
|
A Ilocation |
Max |
Available | |
|
ABCD |
ABCD |
ABCD | |
|
p |
0 0 12 |
0 0 12 |
15 2 0 |
|
p T |
10 0 0 |
17 5 0 | |
|
P z |
13 5 4 |
2 3 5 6 | |
|
p 3 |
0 6 3 2 |
0 6 5 2 | |
|
P A |
0 0 1 Y4 |
0 6 5 6 |
Answer the foflowingquestions using the Bankers algorithm: 10
(i) Whal Is (he content of the matrix Need ? PCS 3002 4 Contd.
f
* *
(ii) Is the system in a safe state ? 1/ so, what is the safe sequence ?
(iii) If a request from a process P arrives for (0, 4* 2, 0} can the request be granted immediately ?
(a) Explain the uses of any ten different commands of UNIX. 5
(b) What is access control verification 7 _ _ -. Explain with example. 5
IWL
'-'S. Describe paged-segmented memory .management technique in details. 10
Consider the following page reference string:
1,2>3A2,l|f5,6,2,1,2,3.7,6,3,2,1,2,3,6
How many page faults would occur for the following replacement algorithms, assuming one and two frames ? Remember all frames are PCS 3002 5 P.T.O.
initially empty, so your first unique pages will all cost one fault each, 10
(i) LRU replacement
fii) FfFO replacement
(iif) Optimafrepfacement.
7, (a) Compare and contrast between siatic and
dynamic partitioned memory management technique. 5
(b) Discuss various types oi operating systems.
5
8, Suppose that the head of a moving-head disk with 200 tracks, numbered 0 to 199, is currently serving a request at track 143 and has just finished a request at 'track 125. The queue of requests is kept in the FiFO order:
86,147,91,177,94,150,102,175,130 PCS 3002 6 Contd.
Whai is the total number of head movements needed to satisfy these requests for the following disk-scheduling algorithms ? 10
(a), FCFS scheduling
(b) SSTF scheduling (c} SCAN scheduling
(d) LOOK scheduling
(e) C'SCAN scheduling.
-C
_
PCS 3002 7
|
Attachment: |
| Earning: Approval pending. |
