OPERATING
SYSTEM EXAMINATION
TOTAL MARKS:100 TIME:
3 Hours
Note: (i) Attempt ALL questions.
(ii)
All questions
carry equal marks.
(iii)
Be precise in
your answer.
Q1. Attempt all parts of the following: (5*4=20)
(a) Define operating system and prove the statement
,”operating system works as a resource manager”.
(b) Discuss
different types of operating system in brief.
(c)Write down
short notes on the following-
(i) Spooling (ii) System call (iii) System program
(e) What are the advantages of the layered
approach to system design?
Q2. Attempt any
four parts of the following, (e) part is compulsory: (5*4=20)
(a) What are the five major activities of an operating
system in regard to process management?
(b) What is the purpose of the command interpreter?
Why is it usually separate from kernel?
(c)Write down short notes on the following-
(i) Context
switch (ii) Scheduler
(d) What are the benefits and the detriments of each
of the following?
(i) Direct
and indirect communication
(ii) Symmetric
and asymmetric communication
(e) Consider the interprocess-communication scheme
where mailboxes are used.
(i) Suppose a process P wants to wait for two
messages, one from mailbox A and one from mailbox B. What sequence of send and
receive should it execute?
(ii) What
sequence of send and receive should P execute if P wants to wait for one
message from mailbox A or from mailbox B (or from both)?
Q3. Attempt all parts of the following: (15*2=30)
(a) Using
preemptive Priority, Round Robin
(quantum=5) ,shortest remaining time
first ,calculate average waiting time and average turnaround time with the following data—(assume 1 means highest priority)
Process Arrival time Priority CPU burst time(ms)
p1 0 4 8
p2 1 3 4
p3 2 2 12
p4 3 1 5
.(b) Solve following question using earliest deadline
first method and also show is there any process would incur deadline overrun?
Q4. Attempt any
two parts of the following, part ( b) is compulsory: (15*2=30)
(a) (i)A binary semaphore is a semaphore with an
integer value that can range only between 0 and 1. Show how a general semaphore
can be implemented using binary semaphores.
(ii) Write
down producer consumer problem using semaphores.
(b) Consider
the following snapshot of a system
Allocation Max Available
A B
C A B
C A B
C
P0
0 1 0 7 5
3 3 3
2
P1
2 0 0 3 2
2
P2
3 0 2 9 0
2
P3 2
1 1 2 2
2
P4
0 0
2 4 3 3
(i)
calculate NEED matrix
(ii)
Is this system in safe state?
(iii)
If a request (1,0,2) for process
p1 can be granted immediately.
(c) (i) Explain and solve Readers – Writers problem using
Semaphores.
(ii)
Explain necessary and sufficient condition for occurring deadlock.
