Assignment 4

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14 Δεκ 2013 (πριν από 3 χρόνια και 5 μήνες)

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KRISHNA INSTITUTE OF ENGINEERING & TECHNOLOGY

Department of Computer Application

MCA
-
311 Operating System

Unit


Four : Storage Management (Question Bank)


1.

Discuss in detail implementation of paging technique with respect to address
mapping, page table, pa
ge size and hardware support for paging. [Describe the
paging scheme of memory management with reference to the hardware required to
support the system. ]

2.

Explain the difference between internal fragmentation the external fragmentation.
Which one occurs in

paging system? OR [
Explain the difference between internal and
external fragmentation.]

3.

Differentiate between Page and Segment.

4.

Explain
Swapping

5.


What is the cause of thrashing? What steps are taken by the system to eliminate
this problem?

OR [Describe t
h
rashing
] OR [
What do you understand by Thrashing?
Wh
at are measures taken to avoid
thrashing?
] [
When do page faults occur? Describe the
actions taken by the operating system when a page fault occurs.
]

6.


What do you understand by Belady’s anomaly. Which pop
ular page replacement
algorithm suffers from the Belady’s anomaly? Also give the name of the class of
algorithms, which can never suffer from Belady’s anomaly and why?
[Explain
Belady’s anomaly with the help of an example.]

7.


Describe the First Fit, Best Fi
t and Worst Fit memory
allocation
Algorithms.

8.


Why are segmentation and paging sometimes combined into one scheme? Explain with
example. [UPTU, 2004]

9.

Describe a mechanism by which one segment could belong to the address space of
two different processes. [U
PTU, 2008]

10.


What do you mean by demand paging?


Explain.

11.

Describe

o
verlay

12.

Differentiate between:

(i)

Block and character devices.

(ii)

Blocking and non
-
blocking I/O.

(iii)

Link list and bit map approach for free space memory management.

(iv)

Double buffering and single buffe
ring.

(v)

Deadlock Prevention and Avoidance

[
What are block and character devices? Differentiate between blocking and non
-
blocking I/O devices.
]

13.


Why must the bit map for file allocation be kept on mass storage, rather

than in main
memory?

14.

Consider a system wh
ere free space is kept in a free
-
space list.

(
a
)

Suppose that the pointer
to the free
-
space list is lost. Can the system

reconstruct the free
-
space list? Explain your
answer.

(
b
)

Suggest a scheme to ensure that the pointer is never lost as a result

of memo
ry
failure.

15.


Double buffering and single buffering.

16.


Differentiate between pre
-
paging and demand paging.

17.

Write short notes on the following:


(a)
Temporal and spatial locality of reference


(b)
Memory protection mechanism


(c)
Memory allocation algorithms

18.
None of the disk scheduling discipline, except FCFS, are truly fair (starvation may
occur) Explain why this assertion is true. (i)
Describe a way to modify algorithms such
as SCAN to ensure fairness. (ii) Explain why fairness is an important goal in

a time
-
sharing system.

(iii)
Give two examples of circumstances in which it is important
that the operating system be unfair in serving I/O requests.

19.

Discuss any two disk scheduling algorithm in brief.

OR [
Discuss Elevator
Algorithm for disk scheduling w
ith examples.
]

20.

Discuss various file allocation strategies for disk space management. OR [Consider a
system that supports the strategies of continuous, linked and indexed allocation.
What criteria should be used in deciding which strategy is best utilized f
or a
particular file?] OR [
Discuss the Contiguous, Linked, Index and Multilevel Indexing file
allocation schemes.]

21.

Latency optimization usually has little effect on system performance except under heavy
loads. Why?