OPERATING SYSTEMS
BY
Mr. B. ANIL KUMAR
Assistant Professor
CSE Department
COURSE OBJECTIVE
This course has two components: a theory component to teach you the
concepts and principles that underlie modern operating systems, and a practice
component to relate theoretical principles with operating system implementation. In the
theory component, you will learn about processes and processor management,
concurrency and synchronization, memory management schemes, file system and
secondary storage management, security and protection, etc. The practice component
will complement the theory component through programming assignments illustrating
the use and implementation of these concepts. At the end of the course you should be
enabled to :

Outline the fundamental operating system abstractions such as processes, threads, files,
semaphores, IPC abstractions, shared memory regions, etc.,

Define how the operating system abstractions can be used in the development of
application programs, or to build higher level abstractions,

Explain how the operating system abstractions can be implemented,

Outline the principles of concurrency and synchronization, and apply them to write
correct concurrent programs/software,

Understand basic resource management techniques (scheduling or time management,
space management) and principles and how they can be implemented. These also include
issues of performance and fairness objectives, avoiding deadlocks, as well as security and
protection.
REFERENCE MATERIAL
SUGGESTED BOOKS:
TEXT BOOKS:
T1:.Operating System Concepts- A Silberchatz, Galvin, 8th edition, John Wiley
T2: Operating System- A Concept based Approach- D M Dhamdhere, TMH
T3: Modern Operating Systems, Andrew S Tanenbaum 2nd edition Pearson/PHI
WEB REFERENCES:
1. http://en.wikipedia.org/wiki/Operating_systems
2. http://www.cse.iitb.ac.in/~rkj/osweb/lectures/semaphores.pdf
3. http://www.vmware.com/virtualization/virtual-machine.html
4. http://web.cs.wpi.edu/~cs3013/c07/lectures/Section08-Memory_Management.pdf
5. http://www.cs.utexas.edu/users/lorenzo/corsi/cs372/03F/notes/11-20.pdf
LEGEND
LECTURE PLAN
UNIT
No.
Lecture
Plan
S.No.
1
2
3
6
Introduction to OS
Overview of Computer Systems
Operating Systems Functions, Protection & Security
Classes of Operating Systems – Distributed Systems
etc.
Os Services , System Calls , System programs
Os Structures – Monolithic , kernel ,Microkernel
7
Virtual Systems ,Operating System Generation ,
4
I
5
8
II
9
10
11
12
13
14
15
III
16
17
18
19
20
IV
V
Topics
21
22
23
24
25
26
27
28
29
30
31
32
Ref.
Materia
ls
Teaching
Methods
No.of
Classes
T1
T1
T1
T2
BLACK BOARD
BLACK BOARD
BLACK BOARD
BLACK BOARD
1
2
1
2
T1
T2
BLACK BOARD
BLACK BOARD
1
1
BLACK BOARD &
WORKINGMODEL
1
(Pg.604-613)
Total Number of HRS :
Process Concepts –operations, states , PCB ,
scheduling and IPC
Threads , Thread Scheduling
Process Scheduling – criteria ,algorithms
Algorithm evaluation
Case Studies : UNIX ,Linux ,Windows
Total Number of HRS :
Principles of Concurrency ,Critical Section Problem
Peterson’s solution ,Synchronization Hardware
Semaphores
Classic problems of Synchronization – Philosophers
problem etc.
Monitors
Atomic Transactions
Synchronization in UNIX ,Linux ,Windows
Total Number of HRS :
Introduction
to
Memory
Management
,
Requirements
Swapping , Contigous Memory allocation
Paging , Page Table
Segmentation
Virtual Memory
Demand Paging , Page Replacement Algorithms
Memory Management in Linux ,UNIX , Windows
Total Number of HRS :
System Model
Deadlock Characterization
Deadlock prevention
Deadlock detection
Deadlock avoidance
Recovery From Deadlock
Total Number of HRS :
T1
09
T1
BLACK BOARD
2
T2
T1
T1
T2
BLACK BOARD
SLIDES
BLACK BOARD
BLACK BOARD
T1
T1
T1
T1,T2
BLACK BOARD
BLACK BOARD
BLACK BOARD
BLACK BOARD
1
2
1
2
08
1
1
1
2
T1
T1
T2
BLACK BOARD
BLACK BOARD
BLACK BOARD
T1
BLACK BOARD
T1,T2
T1,T2
T1,T2
T1
T1
T1
BLACK BOARD
BLACK BOARD
BLACK BOARD
BLACK BOARD
SLIDES
BLACK BOARD
T1
T1,T2
T1,T3
T1,T3
T1
T1,T3
BLACK BOARD
BLACK BOARD
BLACK BOARD
PPT
PPT
PPT
1
1
1
08
1
1
2
1
1
2
1
09
1
1
2
2
2
08
T1
BLACK BOARD
1
T1,T2
BLACK BOARD
1
T1,T2
T1,T2
BLACK BOARD
BLACK BOARD
1
File system implementation and virtual T1
file system
Directory implementation and allocation T1
methods
Free space management and log structured T3
file system Learn about example file
system(NFS, WAFL..)
Total Number of HRS :
T1
Mass-storage structure
Disk structure
T1,T2
T1,T2
Disk scheduling algorithms
Magnetic Disk
T1,T2
T1
Disk management
Swap space management
T1
T1,T2
RAID
Stable storages
T2
T3
Tertiary storage structure
T1
Dining philosopher’s problem
T1
Blocking and non-blocking I/
T1,T3
I/O hardware and types of devices
T3
Kernel I/O subsystem
T2
Life cycle of and I/O request
T1
Streams
Total Number of HRS :
T1
Problems of protection and design a
model for implementing protection,
Types of threats to security
Malicious programs, Access matrix , T1,T2
access control and access capability
T1,T2
Language based protection(JAVA)
BLACK BOARD
1
1
BLACK BOARD
1
Security
problems,Security
T1,T3
threats(Trojan horse, trap door,
logic
bomb)
and
viruses,Network threats(worms,
port scanning, DoS)
Cryptography
and
USER T1
Authentication,Learn about intrusion
detection, firewalls
Total Number of HRS :
BLACK BOARD
Overview of file management ,File
organization and access
File directories and file sharing,Record
Blocking
Secondary storage management
Layered file system
VI
VII
VIII
PPT
BLACK BOARD
2
08
1
BLACK BOARD
BLACK BOARD
1
BLACK BOARD
PPT
BLACK BOARD
BLACK BOARD
1
1
1
1
PPT
BLACK BOARD
BLACK BOARD
1
1
1
1
10
BLACK BOARD
2
BLACK BOARD
1
BLACK BOARD
1
BLACK BOARD
2
2
10
UNIT – I
LEARNING OBJECTIVES:
At the end of this unit the student must be able to

Outline the importance of Operating system.

List the services provided by Operating System.

Define the overview of computer system hardware.

Explain the role of system calls and their types .

Outline different Classes of OS

Compare and Contrast Symmetric and Asymmetric multiprocessing

Analyze essential properties of different types of operating systems

Outline the major activities of an OS

Identify operating system protection and security factors
ASSIGNMENT/ DISCRIPTIVE QUESTIONS
1. Define OS ? Explain about goals and services of OS briefly
2. Explain about storage structure and I/O structure of computer system
3. Explain evolution of OS .
4. Explain different structures of OS briefly .
5. What is Booting ? Explain the importance of Bootstrap Program
6. What is a Virtual Machine ? Explain about VMware architecture.
7. Define System Call and explain distinct types of System Calls elaborately.
8. Justify the following statements.
(a) OS can be viewed as a Resource Allocator.
(b) OS is a Control Program
9. What are the major activities of an operating system with regard to process management?
10. Differentiate Distributed systems from Multiprocessor systems.
11. Some CPUs provide for more than two modes of operation. What are two possible uses
of these multiple modes? Explain.
12. Explain the basic instruction cycle with appropriate diagram.
13. Interrupts are the important part of Computer Architecture. Justify your answer with
appropriate interrupt time line diagram.
14. What are the main differences between operating systems for Mainframes and PCs?
Discuss.
15. What are the drawbacks of Interrupt driven I/O and Programmed I/O? How they are
overcome?
16. Define Os ? Explain evolution of OS .
17. Define System Call and explain distinct types of System Calls elaborately.
OBJECTIVE QUESTIONS
1. Which one of the following contains the address of the next instruction to be fetched
a)Instruction Register b)Program Counter
c)Address Register
d)Data
Register
2. The Hardware allows privileged instructions to be executed only in _______ mode.
a)User
b)Kernel
c)Both
d)None
3. __________ provides an interface to the services made available by an operating System.
a)Operating System
b)Interrupts
c)System Calls
d)None
4. Kernel is __________________
a)considered as the critical part of the os
b)the software which monitors the os
c)the set of primitive functions upon which the rest of os functions are built up.
d)User defined program.
5. Which of the following service is not supported by OS
a)Protection
b)Accounting
c)Compilation
d)I/O
operation
6. The ________ determines the nature of the interrupt and performs necessary actions .
a)Interrupt request b)Interrupt stage c)Interrupt Service routine
d)Interrupt
routine
7. DMA stands for ________
a)Delay memory access
b)Direct Memory Advice
c)Device Model Access
d)Direct Memory Access
8. _______________ are provided primarily to improve processor utilization
a)Flags
b)Interrupts
c)Signals
d)Kernels
9. _____________ memory is placed between CPU and main memory.
a)Read-only
b)Random Access
c)Cache
d)Flash
signal
10. OS objective is to provide _______
a)Inconvenience
b)Inefficiency
c)Error Correction
d)Ability
to
evolve
11. Distributed Systems should_______________________
a)meet prescribed time constraints
b)aim better resource sharing
c)aim better system utilization
d)aim low system overhead
12. Spatial locality refers to the problem that once a location is referenced
a)it will not be referenced again
c)a nearby location will be referenced soon
b)it will be referenced again
d)none of the above.
13. ______________________ abstracts the hardware of a single computer into several
different execution environments , thus creating an illusion that each environment is
running on its private machine.
14. In a computer system , a small piece of code known as ____________ locates the kernel ,
loads it into main memory , and starts its execution at the time of system start up.
15. SMP stands for _________________________________________.
UNIT – II
LEARNING OBJECTIVES:
At the end of this unit the student must be able to

List the common events that lead to the creation of a process.

Define process control block .

Outline the steps performed by an OS to create a new process

Identify different process states .

Define short term , medium term and long term scheduling

Compare Context and Process switching

Explain process management in UNIX, LINUX and WINDOWS.

Compare and contrast between thread and process

List the benefits of multithreaded programming and their models

Explain threads in Unix, Linux and Windows

Define types of CPU scheduling and their criteria for being the best with examples
ASSIGNMENT/ DISCRIPTIVE QUESTIONS
1. Compare and Contrast Process switching , Context switching .
2. Define Process ? Describe the typical elements of Process control block.
3. Discuss the following: a)user-level threads b)kernel-level threads c)multi-threading
4. a) Explain about all the states of a process with a neat diagram
b) Explain about all CPU scheduling algorithms with examples
5. Explain about process creation and termination in UNIX
6. Explain about multithreading models
7. Explain about the types of schedulers and their functionality .
8. Explain the need for Inter process Communication and techniques for communication .
9. Elaborate on Need for process Scheduling and Scheduling Criteria ?
10. i)FCFS ii)SHORTEST JOB FIRST
iv)RR (TQ=1)
iii) SHORTEST JOB FIRST (PREEMPTIVE)
11. Explain about single threaded and multi threaded process models with suitable diagrams.
12. Explain the following process state transitions:
(a) Blocked ! Blocked/Suspended.
(b) Blocked/Suspended ! Ready/Suspended.
(c) Ready/Suspended ! Ready.
13. (a) What are the various examples of the uses of the threads in a single user
multiprocessing system?
(b) What are the key benefits of threads derived from the performance implications?
14. (a) What is a thread?
(b) What are the benefits of the threads?
(c) Explain about user level and kernel level threads.
15. (a) What are the two separate and potentially independent characteristics embodied in the
concept of the process? Discuss.
(b) What resources are typically shared by all of the threads of a process?
16. What are various steps involved in change of a process state? Explain in detail?
17. What are the various reasons for process suspension? Explain.
18. Explain about the following.
19. (a) Process identification.
(b) Processor state information.
20. a) Explain about all the states of a process with a neat diagram
b) Explain about all CPU scheduling algorithms with examples
21. Explain about process creation and termination in UNIX
(a) Discuss with examples the three types of processor scheduling.
(b) Differentiate between turn around time and response time.
OBJECTIVE QUESTIONS
1. In a heavily loaded system , a steady stream of higher-priority processes can prevent a
low-priority process from ever getting CPU , this is known as ___________
a) Deadlock
b)Aging
c)Scheduling
d)Starvation.
2. The _____________ scheduler selects process from the processes ready for execution
and allocates the CPU to that process.
a)Short-term
b)Long-term
c)Medium term
d)Low-level
3. Pre-emptive scheduling , is the strategy of temporarily suspending a running process
_______
a) before the CPU time slice expires
b)to allow starving processes to run
c)when it requests I/O
d)none of the above.
4. Suppose that a process is in BLOCKED state waiting for some I/O service . When the
service is completed , it goes to the _______________ state.
a)RUNNING state
b)READY state
c)SUSPENDED state d)TERMINATED
state
5. Which of the following scheduling policy is well suited for a time-shared operating
system?
a)SJF
b)Round Robin
c)FCFS
d)Elevator.
6. A small program known as __________ , switches the processor from one process to
another.
a)Bootstrap
b)Dispatcher
c)Running
d)kernel
7. The Time elapsed between , process submission to its total completion is known as
_______
a) Wait time
b)Response time
c)Turn around time
d)Throughput
8. Process creation in UNIX is made by means of the ___________ system call
a)create()
b)join()
c)fork()
d)delay()
9. ___________ is a solution to process starvation.
a)Slicing
b)Aging
c)prevention
d)Deadlock.
1. A _____ is the maximum amount of time that a process can execute before being
intercepted .
a)time state
b)time slice
c)time in
d)time out.
2. The __________ is the key tool that enables the os to support multiple processes and to
provide for multi processing .
a)Process Control Block
b)State Control block
c)Thread Control block d)Register Control
block
3. The possible transition of five state process model is
a)Ready – Blocked
b)New – Running
c)New- Ready
d)Blocked - Running
4. The two fundamental models of Inter process Communication are _________and
________.
10. 14.PCB stands for ____________________________________.
5. __________________ is a light weight process.
UNIT – III
LEARNING OBJECTIVES:
At the end of this unit the student must be able to

Outline the concept of concurrency and the affect of the execution of
multiple concurrent processes.

List the basic requirements of mutual exclusion for concurrent processing

Define various software and hardware approaches to achieve mutual
exclusion

Explain semaphores, monitors and message passing.

Outline the problems with concurrent atomic transactions.

Explain synchronization in UNIX , LINUX and WINDOWS.
ASSIGNMENT/ DISCRIPTIVE QUESTIONS
1. What are the principles of concurrency ? Explain in detail how concurrent process come
into
conflict with each other when they are competing for the use of the same
resource
2. What is a semaphore? Explain the operations performed on Semaphores
3. Explain in detail the requirements of Critical Section problem solution.
4. Define a Monitor ? Derive a Deadlock free solution for Dining Philosophers problem
using Monitors .
5. Explain about infinite buffer producer/consumer problem for concurrent processing
which uses binary semaphores .
6. State Readers / Writers Problem
and derive a solution for First Readers / Writers
Problem using Semaphores ?
7. Define Mutual Exclusion ? Explain the Hardware solutions to achieve for critical section
problems
8. Explain the Peterson’s solution for solving Critical section Problem.
9. Define the following Terms
a) Spin Locks
b)
Binary
,
Semaphores
c) Atomic Transactions – Checkpoints
d)Serializability.
Counting
10. a) Define an Atomic Transaction ?
Explain Log- Based Recovery
for atomic
transactions ?
b) Explain Time – stamp based Protocols for ensuring consistency
in
atomic
Transactions ?
11. Write the short notes on the following
a) Race Condition
b) Process Interaction
12. Explain the solution for the critical section problem for multiple processes.
13. Define monitor. What are its characteristics?
14. What is critical section problem? Explain with example.?
15. a) What is the need for mutual exclusion?
b) What is a critical resource?
c) What is a critical section?
d) What is starvation?
16. Explain the Readers/Writers problem and its solutions.?
17. Explain the solution to Dining Philosophers Problem using Semaphores.
18. Explain the Peterson’s solution for solving Critical section Problem.
19. What are the principles of concurrency ? Explain in detail how concurrent process come
into
conflict with each other when they are competing for the use of the same resource
20. What is a semaphore? Explain the operations performed on Semaphores
21. Explain in detail the requirements of Critical Section problem solution.
22. a) Define an Atomic Transaction ?
Explain Log- Based Recovery
for atomic
transactions ?
b) Explain Time – stamp based Protocols for ensuring consistency
in
atomic
Transactions ?
OBJECTIVE QUESTIONS
1. A _________ occurs when multiple processes or threads read and write data items so that
the final result depends on the order of instructions in the multiple processes.
a)Critical Section
Condition
b)Deadlock
c)SpinLock
d)Race
2. If a schedule S can be transformed into a serial Schedule S’ by a series of swaps of non
conflicting operations , then the schedule S is said to be _________.
a)Serializable
b)Concurrent
c)Conflict Serializable
d)
None
3. A situation in which a runnable process is overlooked indefinitely by schedule is known
as___
a)starvation
b)Deadlock
c)live lock
d)race
c)Mutex
d)Spooling
condition
4. Binary semaphore is also known as
a)General semaphore
b)Cluster
5. For both counting and binary semaphores , a _________ is used to hold processes waiting
on the semaphore
a)stack
b)dequeue
c)queue
d)circular
queue
6. If the data in a monitor represents some resource , then the monitor provides a ______
facility for accessing the resource.
a)preemption
b)non preemption
c)hold and wait
d)mutual
exclusion
7. In Readers / Writers problem
a) If a writer is writing to the file ,two readers may read it.
b) If a writer is writing to the file ,one reader may read it.
c) Only one reader at a time may read the file.
d) Only one writer at a time may write to the file.
8. The return value of test and set instruction is
a)integer
b)character
c)Boolean
d)float
9. The __________ is a programming construct that provides equivalent functionality to
that of semaphores and that is easier to control.
a)monitor
b)signal
c)critical section
d)mutex
10. can the producer / consumer problem be considered a special case of the readers/writers
problem with a single writer(producer) and a single reader(consumer)
a)Yes
b)No
c)Cannot say
d)Sometimes possible
11. ___________________ is an integer variable that , apart from initialization , is accessed
through two standard operations : wait () and notify().
a)Monitor
b)Spinlock
c)Deadlock
d)Semaphore
12. The solution to the critical section problem must satisfy ____________
,
_____________and
________________ requirements.
13. Each process has a segment of code , called a _________________,in which the process
may be changing common variables, updating a table, writing a file ,and so on.
14. _______________ is a situation where two or more processes are waiting indefinitely for
an event that can be caused only by one of the waiting processes.
15. In two phase locking protocol there exists two phases namely _____________ and
___________ phases.
UNIT – IV
LEARNING OBJECTIVES:
At the end of this unit the student must be able to

Define the need to study memory management in operating systems

Identify the memory management requirements

Explain about loading programs into main memory

List different memory management techniques

Define importance of virtual memory

Learn about the application of virtual memory

Calculate page faults using different Page replacement algorithms

Explain Memory management in UNIX , LINUX and WINDOWS environment
ASSIGNMENT/ DISCRIPTIVE QUESTIONS
1. Explain with a neat sketch
i)
Address translation in a segmentation system
ii)
Address translation in a paging system
2. i) Discuss the differences between a pure paging and demand Paging Virtual memory
systems. What are the pros and cons of each scheme?
ii) What are the three main issues of implementing a virtual memory?
iii) Comment on the relative merits of using a local versus a global page replacement
policy
3. State and explain the various page replacement algorithms in detail?
4. a)Differentiate between demand cleaning and pre-cleaning
b)What is the difference between resident set and a working set
c) Explain with suitable examples about page replacement algorithms
5. Write short notes on
a) Compaction
b)Translation look aside buffer
c) Internal and External
Fragmentation
6. Elaborate on Different Page Table Structures .
7. a) Define Thrashing ? Explain The working set model in detail ?
b) A process has 4 frame allocated to it. Calculate the number of page faults using
following page replacement algorithms for the reference string
4,0,0,0,2,4,2,1,0,3,2.
i)
i. OPTIMAL
ii. SECOND CHANCE
iii.LRU
8. Explain the role of Translation Look-Ahead Buffer(TLB) in paging ?
9. Compare the main memory organization scheme of contiguous memory allocation,pure
segmentation and pure paging with respect to the following issues.
a) External fragmentation
b) Internal fragmentation
c) Ability to share code across processes.
10. Explain contiguous memory allocation scheme for memory management. What are its
advantages and disadvantages?
11. a) Contrast resident set with working set.
b) What are the advantages of an inverted page table? Explain.
12. Explain paging scheme for memory management. Discuss the paging hardware and
paging model.
13. a) Explain Paging hardware with translation look-aside buffer.
b) How memory protection can be accomplished in a paged environment? Explain.
14. a) Compare global and local page replacement algorithms. What are the advantages of
each?
b) Describe two-level paging. What problems two-level paging tries to solve?
15. i) Discuss the differences between a pure paging and demand Paging Virtual memory
systems. What are the pros and cons of each scheme?
ii) What are the three main issues of implementing a virtual memory?
iii) Comment on the relative merits of using a local versus a global page replacement
policy
16. Write short notes on: a) Compaction b)Translation look aside buffer c) Internal and
External Fragmentation
17. Elaborate on Different Page Table Structures .
OBJECTIVE QUESTIONS
1. If the process can be moved during its execution time from one memory segment to
another, then ________ binding is used.
a)Compile Time
b)Runtime
c)Load Time
d)Static
2. TLB stands for_______
a)Translation Log Based
b)Translation Look-aside Buffer
c)Translation Log Buffer
d)Transaction Log Buffer
3. Segmentation Suffers from ________.
a)Internal Fragmentation
b)External Fragmentation c)Both
d)None.
4. Virtual memory is ________
a)an extremely large main memory
b)an extremely large secondary memory
c)a type of memory used in super computers d)an illusion of an extremely large memory.
5. The first fit,best fit and worst fit algorithms can be used for
a)linked allocation of memory
b)contiguous allocation of memory
c)hash allocation
d)indexed allocation of memory
6. The runtime mapping from virtual to physical address is done by ___
a)scheduler
b)OS
c)CPU
d)Memory management Unit
7. The address generated by CPU is known as _________
a)zero
b)logical
c)physical
d)true
8. The maximum value for logical address=y and base register value=x , what is the
maximum value for physical address ?
a) x+y
b)x-y
c)x*y
d)x/y
9. The page fault occurs when
a)the page is corrupted by application software
b)the page is in main memory
c) the page is not in main memory
d)One tries to divide a number by 0.
10. ______________ algorithm fits the process into the largest available hole.
a)first fit
b)best fit
c)worst fit
d)zero fit
11. ____________________ algorithm searches the list of holes and allocate the first
memory area that is large enough
a)first fit
b)best fit
c)worst fit
d)zero fit
c)stack
d)list
12. To implement LRU _______ data structure is used.
a)queue
b)tree
13. A process is ______ if it is spending more time paging than executing.
a)routing
b)filtering
c)locked
d)thrashing
14. Replace the page that has not been used for longest period of time. This is __
a)FIFO
b)LFU
c)LRU
d)MFU
15. In ____________________ technique , the memory contents are shuffled so as to place
all
free memory together in one large block.
UNIT – V
LEARNING OBJECTIVES:
At the end of this unit the student must be able to

Identify the cause of Deadlock

List necessary condition for Deadlock

List the methods that an operating system can use to deal with deadlock problem

Identify tool in characterizing the allocation of resources to processes like
Resource Allocation Graph (RAG)

outline the Deadlock detection mechanisms

outline the Deadlock avoidance Statergies

Predict whether the System ends up in an unsafe state upon granting a request made by a
process.

Explain Deadlock detection and recovery stratergies .
ASSIGNMENT/ DISCRIPTIVE QUESTIONS
1. What is deadlock? Prove that an unsafe state is not deadlock state. Explain the
necessary
conditions for the deadlocks.
2. What is deadlock avoidance? Explain process initiation denial and resource allocation
denial in detail with example
3. What are the principles of deadlock? And explain in detail the two categories of
resources
4. What are the conditions that must satisfy for deadlock occurrence and explain them ?
5. Is the deadlocks problem preventable? Justify your answer with example and diagram.
6. Write the resource allocation algorithm for Deadlock detection.
7. (a) What is the need for mutual exclusion?
(b)What is a critical resource?
(c) What is a critical section?
(d) What is starvation?
8. Explain about Deadlock Prevention.
9. Explain about Deadlock Avoidance.
10. Explain the algorithm to recover from deadlocks.
11. Describe a system model for study of deadlock situation.
12. Explain the Bankers algorithm for deadlock avoidance with suitable example.
OBJECTIVE QUESTIONS
1. Mutual exclusion
a) if one process is in a critical region others are excluded
b) prevents deadlock
c) requires semaphores to implement d) is found only in the Windows NT operating
system `
2. The section of code which accesses shared variables is called as __________.
a) Critical section
b) Block
c) Procedure
d)
Semaphore
3. In one of the deadlock prevention methods, impose a total ordering of all resource types,
and require that each process requests resources in an increasing order of enumeration.
This violates the _______________ condition of deadlock
a) Mutual exclusion
b) Hold and Wait
c) Circular Wait
d) No
Preemption
4. A critical region
a) is a piece of code which only one process executes at a time b) is a region prone to
deadlock
c) is a piece of code which only a finite number of processes execute
d) is found only in Windows NT operation system
5. Let S and Q be two semaphores initialized to 1, where P0 and P1 processes the following
statements wait(S);wait(Q); ---; signal(S);signal(Q) and wait(Q);
wait(S);signal(Q);signal(S); respectively. The above situation depicts a _________ .
a) Semaphore
b) Deadlock
c) Signal
d) Interrupt
6. The solution to Critical Section Problem is : Mutual Exclusion, Progress and Bounded
Waiting.
a) The statement is false
b) The statement is true.
c) The statement is contradictory .
d) None of the above
7. _________ is the situation in which a process is waiting on another process, which is also
waiting on another process ... which is waiting on the first process. None of the processes
involved in this circular wait are making progress.
a) Deadlock
b) Starvation
c) Dormant
d) None of the above
8. The Bankers algorithm is used
a) to prevent deadlock in operating systems
b) to detect deadlock in operating
systems
c) to rectify a deadlocked state
d) none of the above
9. Situations where two or more processes are reading or writing some shared data and the
final results depends on the order of usage of the shared data, are called ________.
a) Race conditions
b) Critical section
c)Mutual exclusion
d) Dead locks
10. When two or more processes attempt to access the same resource a _________ occurs.
a) Critical section
b) Fight
c) Communication problem d) Race
condition
11. _____________ are commodity required by a process to execute.
12. RAG Stands for _______________.
13. If RAG contains no cycle this there is _________.
14. Banker only lends resources if the system will be in a _______state after the loan.
15. If a system is in unsafe state then there is _______________.
UNIT – VI
LEARNING OBJECTIVES:
At the end of this unit the student must be able to

Define file management system

List the various file organization and access methods

List the various file directory structures

Define Record blocking

D efine file sharing

Examine the problems of protection and design a model for implementing protection

Discuss about layered file system

Differentiate file system implementation and virtual file system

D o directory implementation

List allocation methods

Define free space management

Define log structured file system

List the example file system(NFS, WAFL..)
ASSIGNMENT/ DISCRIPTIVE QUESTIONS
1. Write short notes on:
i)Sequential file
ii) Indexed file
iii) Indexed sequential file iv)
file
2. a)Explain in detail the four terms field ,record file and database w.r.t to files
b)List the objectives and the requirements for a file management system
3. What are reallocation, dynamic allocation, portion size w.r.t
4. a)secondary Storage management
b) Describe various file allocation methods
1. a )Define file system architecture
b) What are the important criteria in choosing a file organization?
c) List the functions of a file management system with a diagram
2. Write about a) Free space management b)Reliability of a file allocation
a) List and explain three blocking methods.
b) What is the relationship between a pathname and a working directory?
Direct
c) What criteria are important in choosing a file organization?
3. a) Explain hash file organization.
b) Discuss the address information elements of a file directory
4. Explain various techniques implemented for free space management, discuss with
suitable Explain various techniques implemented for free space management, discuss
with suitable examples. (a) What is the need for mutual exclusion?
5. Discuss the criteria for choosing a file organization.
6. Describe indexed file, indexed sequential file organization.
7. List and explain three blocking methods.
8. What is the relationship between a pathname and a working directory?
9. Give an example of an application that could benefit from operating system support for
random access to indexed files.
10. Explain hash file organization.
11. Discuss the address information elements of a file directory.
12. (a) Explain about various file operations.
(b) Discuss about the usage information elements of a file directory.
13. Explain file sharing. Discuss about the access right and management of simultaneous
access.
14. a) Discuss indexed allocation methods for secondary storage management.
b) What are the advantages and disadvantages of pile file organization over hashed file
organization?
15. (a) Describe the key features of NTFS.
(b) Discuss file allocation method in UNIX file.
OBJECTIVE QUESTIONS
1. File record length
a) should always be fixed
c) depends upon the size of the file
character
b) should always be variable
d) should be chosen to match the data
2. Which types of file organization are supported by magnetic tapes random files
a) random file
b)contiguous sequential file
c) indexed sequential file
d) random & sequential file
3. A file is
a) not an abstract data type
b) not a logical storage unit
c)file is usually non volatile
d) file is usually volatile
4. Number of minimal set of required file operations are
a) two
b) four
c) five
5. Which structure prohibits the sharing of files and directories
a) tree structure
b) one level directory
c) two level
d)six
d) three level
6. The file structure that redefines its first record at a base of zero uses the term
a) dynamic reallocation
b) key fielding
c) relative organization
d)
hashing
7. Disadvantage of single level directory is
a) the confusion of files names between users
b) the confusion of files data
c) the confusion of both file names & file data d)the confusion of neither file name nor
file data
8. Solution of name collision problem is
a) single level directory
b) two level directory c) tree structure
d) three level
directory
9. Path's name are
a) absolute path
b) relative path
c) absolute path & relative path
d) neither absolute nor relative path
10. How many common file type are there
a) one
b) six
c) five
d) two
11. System supports how many types of files
a) one
b) six
c) five
d) two
12. The simplest directory structure is
a) single level directory
b) two level directory
c) tree structure directory
d) three level directory
13. There are no cycle in which type of directory
a) General graph directory
b) Acyclic graph directory
c) One level directory
d) Two level directory
14. A file sometimes called a
a) collection of input data
b) program
c) temporary place to store data
d)data
set
15. OS abstracts from the physical properties of its storage device to define a logical storage
unit called __________.
UNIT – VII
LEARNING OBJECTIVES:
At the end of this unit the student must be able to

Define magnetic disk

List disk scheduling algorithms

Define disk management

Outline swap space management in UNIX

Define RAID in

List the stable storages

Learn about tertiary storage structure

Learn the dining philosopher’s problem

Learn about I/O hardware, polling and interrupts

Learn about DMA

Learn about block , character and network devices

Learn about STREAMS
ASSIGNMENT/ DISCRIPTIVE QUESTIONS
1. a) Explain various disk Performance parameters.
b) Show that the use buffer can reduce the running time by at most a factor of
two.
2. Suppose 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. If the queue of requests is kept in FIFO order: 86, 147, 91, 177, 94, 150,
102, 175,130. What is the total head movement to satisfy these requests for the
following disk scheduling algorithms.
a) FCFS (b) Random (c) PRI (d) SCAN (e) SSTF (f) C- SCAN
3. a) Discuss about N- step- SCAN policy for disk scheduling.
b)Explain how double buffering improves the performance than a single buffer
for I/O.
c) Differentiate between logical I/O and device I/O.
4. a) Bitmaps are not often used for main memory allocation. They are commonly
used for disk space allocation. Speculate on why this is so.
b) Give an example of an application that could benefit from operating system
support for random access to indexed files.
5. a) Explain about RAID technology
b) Explain about stable and tertiary storage structure
6. What is the dining philosophers problem? Device an algorithm to solve the
problem using semaphores
7. Write detailed notes on :
a) Interrupts
b) I/O communication techniques
8. Explain about devices in I/O interface
9. a)Explain about kernel I/O subsystem
b)Explain about streams
10. Suppose 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. If the queue of requests is kept in FIFO order: 86, 147, 91, 177, 94, 150,
102, 175, 130. What is the total head movement to satisfy these requests for the
following disk scheduling algorithms.
a) FCFS (b) Random (c) PRI (d) SCAN (e) SSTF (f) C- SCAN
11. What the design characteristics of Message Systems are of inter process
communication and synchronization?
12. Discuss about N- step- SCAN policy for disk scheduling.
13. Explain how double burring improves the performance than a single bu er for
I/O.
14. Differentiate between logical I/O and device I/O.
15. Most round-robin schedules uses a fixed size quantum. Give an argument in
favor of a small quantum. Now give an argument in favor of a large quantum.
Compare and contrast the types of systems and jobs to which the argument
apply.
16. With an example explain shortest- Process- Next scheduling.
17. What is the difference between preemptive and non preemptive scheduling?
Explain an algorithm for each scheduling type.
18. Explain Fair-share scheduling policy with an appropriate example. Compare its
performance with any other scheduling policy.
19. a) Describe highest- response- ratio- next scheduling policy with an appropriate
example.
b) Give a detail note on simulation modeling.
OBJECTIVE QUESTIONS
1. Disk scheduling involves deciding
a)which disk should be accessed next
b) the order in which disk access requests must be serviced
c) the physical location where files should be accessed in the disk
d) the length of the files
2. _ _ _ _ _ _ _ _ _ _ is the total number of bytes transferred divided by the total time
between the first request for service and completion of the last transfer.
a) bandwidth
b) seek time
c) latency
d) rotational latency
3. The simplest form of disk scheduling is _ _ _ _ _ _ _
a) FCFS
b) SSTF
c) SCAN
d) C-SCAN
4. In disk scheduling SSTF stands for _ _ _ _ _ _ _ _ _ _
a) shortest seek time first
b) shortest scan time first
c) shortest schedule time first
d) shortest search time first
5. In disk scheduling _ _ _ _ _ _ _ _ _ algorithm is called elevator algorithm
a) FCFS
b) SSTF
c) SCAN
d) C-SCAN
6. ''In UNIX file name translation is done in the file system name space'' is _ _ _ _ _ _ _ _ _
a) always true
say
b) always false
c) some times true some times false c) can't
7. ''In MS-DOS file name translation is done in a separate device name space'' is _ _ _ _ _ _
___
a) always true
b) always false
c) some times true some times false c) can't
say
8. Before a disk can store data it must be divided into sectors that the disk controller can
read /write. This process is called _ _ _ _ _ _ _ _ _ _ formatting
a) low level
b) physical
c) low level or physical
d) logical
9. _ _ _ _ _ _ _ _ formatting fills the disk with a special data structure for each sector
a) low level
b) physical
c) low level or physical
d) logical
10. Creation of a file system is known as _ _ _ _ _ _ _ _ _ formatting
a) low level
b) physical
c) low level or physical
d) logical
11. Which of the following is single user OS
a)MS-DOS
b) UNIX
c) LINUX
d) OS/2
12. Which of the following is secondary storage device
a) register
b) cache
c) disk
d) main memory
13. Before a disk can store data it must be divided into _ _ _ _ _ _ _ _ _ that the disk
controller can read /write
a) track
b) sector
c) surface
d) cylinder
14. _ _ _ _ _ _ _ is a process that holds kernel form disk to main memory
a) blocking b) Booting
c) Bootstrapping
d)Interpreting
15. C-SCAN stands for _ _ _ _ _ _ _ _ _
a) circular scan
b) cycle scan
c) cache scan
d) cube scan
UNIT – VIII
LEARNING OBJECTIVES:
At the end of this unit the student must be able to

Examine the problems of protection and design a model for implementing protection

To understand types of threats to security

Identify and understand the different malicious programs

Learn about access matrix , access control and access capability

Learn about language based protection(JAVA)

Learn about security problems

Learn about security threats(Trojan horse, trap door, logic bomb)

Learn about viruses

Learn about network threats(worms, port scanning, DoS)

Learn about cryptography

Learn about USER Authentication

Learn about intrusion detection, firewalls
ASSIGNMENT/ DISCRIPTIVE QUESTIONS
1. Write short notes on a)viruses b)Worms c) Logic bomb d)Trap door
2. a) What are the security requirements of a computer and network.
b) Explain different types of threats.c) Explain the computer system assets.
3. a) Who are the various classes of intruders. b) Discuss about intrusion techniques
4. Write short notes on a)intrusion detection b)password protection
5. a)How resources of a computer system is protected b)Explain user and data oriented access
control
6. a) Discuss the password file protection mechanisms.
b) Write a detail note on Masquerader, Misfeasor, and clandestine user
7. a) Explain the various password selection strategies.(b) Discuss about UNIX password
scheme.
8. a) Discuss the three options available in Windows 2000 for requesting access.
b) Describe the generic access of Windows 2000.
9. List the various techniques followed by password crackers in learning password.
10. Compare active attacks with passive attacks.
11. Give the classification of intruders. Explain each class.
12. Comparison User-Oriented access control with data-oriented access control.
13. Discuss the three options available in Windows 2000 for requesting access.
14. What is a trusted system? Explain the reference monitor concept and multilevel
secure system in detail.
15. How is the AES expected to be an improvement over triple DES?
16. Explain the flaws in one-way encryption of password strategy.
17. Write a brief note on intrusion detection.
18. a) Discuss about Vulnerability of passwords.
b) Give a note on security attacks.
19. a) Explain in detail passive treats.
b) What is an access matrix?
Explain.
20. Explain the security threats to various computer system assets.
OBJECTIVE QUESTIONS
1. Lowest Level of security system is
a) A
b) B
c) C
d) D
2. An audit log _ _ _ _ _ _
a) simply records the time
b) records user
c) type of all access to an object
d) records time, user & access to an
object
3. The most common approach to authenticating a user identity is _ _ _ _ _ _ _ _
a) user passwords
b) user log in c) hardware device d) user log in & hardware
device
4. A major security problem for OS is _ _ _ _ _ _ _
a) authentication problem
b) physical problem
c) human problem
d) physical & human problem
5. Trojan Horse _ _ _ _ _ _ _ _ _ _ _ _ _
a) A code segment that misuses its file is called Trojan horse
b) good for file
accessing
b) Trojan horse does not misuses its file
d) misuses its file and good for file
accessing
6. Program threats are _ _ _ _ _ _ _ _ _ _ _ _
a) Trojan horse
c) trap doors
c) Trojan horse & trap doors
d)neither Trojan horse nor trap doors
7. In one time password _ _ _ _ _ _ _ _ _
a) the password is different in each instance
instance
c) some times different and some times same
8. Which of the following is not true regarding viruses
a) another form of computer attack is virus
b) the password is same in each
d) can't say
b) virus are designed to spread into other programs and can wreak havoc in a system
c) it modifying or destroying files and causing system crashes
d) viruses are beneficial for program
9. Boot strap or vector is called
a) grappling hook program b) main program
c) secondary program d) primary
storage
10. Two programs of worm are _ _ _ _ _ _ _ _ _ _ _
a) grappling hook program
c) grappling hook & main programs
pgm
b) main program
d) neither grappling hook nor main
11. Worm was made up _ _ _ _ _ _ _ _ _
a) one program
b) two programs
c) three programs
d)
four
programs
12. Trap door _ _ _ _ _ _ _ _ _ _ _
a) could be included in a compiler b) pose a difficult problem because to detect them
c) could be included in a compiler & pose a difficult problem to detect them
d) could not be included in a compiler
13. Applications
a) can not run on multiple processors
b) immediately run on multiple processors
c) must usually be re compiled to use multiple processors
d) can always be made efficient on multiple processors
14. Link encryption
a) is more secure than end to end encryption
b) is less secure than end to end
encryption
c) can not be used in a large network
d) is used only to detect errors
15. Resources are managed _ _ _ _ _ _ _ _ _ _ _ _ _
a) with each processor equally
b) by only one processor
c) by sophisticated locking mechanisms
d) more easily with multiple
processors
ANSWER KEY ALL 8 UNITS
Unit - I:1.B,2.B,3.C,4.C,5.C,6.C,7.D, 8.B,9.C,10.D, 11.B, 12.C ,13. Virtual Machine,14. Bootsrtap
Program, 15. Symmetric Multi processing.
Unit - II:1.D, 2.A, 3.B, 4.B, 5.B, 6.B, 7.C, 8.C, 9.B, 10.B, 11.A, 12.C, 13. Message Passing , Shared
Memory
14. Process Control Block, 15. Thread
Unit - III:1.D, 2.C, 3.A, 4.C, 5.C, 6.D, 7.D, 8.C, 9.A, 10.A, 11.D, 12.Mutual Exclusion , Progress and
Bounded Waiting, 13.Critical section, 14. Deadlock, 15. Growing , Shrinking.
Unit - IV:1.B, 2.B, 3.B, 4.D, .B , 6.D, 7.B, 8.A , 9.C, 10.C, 11.A, 12.C, 13.D, 14.C, 15.Compaction
Unit - V:1.a, 2.a , 3.c, 4.a, 5.b, 6.b, 7.1 , 8.a, 9.a, 10.d, 11. Resources , 12.Resource Allocation Graph,
13. No Deadlock, 14.Safe, 15. possibility of deadlock.
Unit - VI:1.c, 2.b , 3.c, 4.d, 5.a, 6.c, 7.a, 8.b, 9.c, 10.a, 11.b,12.a,13.b, 14.d,15.File
Unit - VII:1.b, 2.a, 3.a, 4.a, 5.c,6.a, 7.a, 8.c, 9.c , 10.d, 11.a, 12.c, 13.b, 14.b, 15.a
Unit - VIII:1.d, 2.d, 3.a, 4.a, 5.a, 6.c, 7.a, 8.d, 9.a , 10.c, 11.b, 12.c, 13.c, 14.b, 15.c