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What is a local block?
A local block is any portion of a C program that is enclosed by the left brace
({) and the right brace (}).

Should variables be stored in local blocks?
The use of local blocks for storing variables is unusual and therefore should
be avoided, with only rare exceptions.
When is a switch statement better than multiple if statements?
A switch statement is generally best to use when you have more than two
conditional expressions based on a single variable of numeric type
.
13. What is the difference between ++var and var++?
The ++ operator is called the increment operator. When the operator is
placed before the variable (++var), the variable is incremented by 1 before it
is used in the expression. When the operator is placed after the variable
(var++), the expression is evaluated, and then the variable is incremented
by 1.
The same holds true for the decrement operator (--). When the operator is
placed before the variable, you are said to have a prefix operation. When the
operator is placed after the variable, you are said to have a postfix
operation.
For instance, consider the following example of postfix incrementation:
int x, y;
x = 1;
y = (x++ * 5);

In this example, postfix incrementation is used, and x is not incremented
until after the evaluation of the expression is done. Therefore, y evaluates to
1 times 5, or 5. After the evaluation, x is incremented to 2.
Now look at an example using prefix incrementation:
int x, y;
x = 1;
y = (++x * 5);
This example is the same as the first one, except that this example uses
prefix incrementation rather than postfix. Therefore, x is incremented before
the expression is evaluated, making it 2. Hence, y evaluates to 2 times 5, or
10.
what is data structure?
A data structure is a way of organizing data that considers not only the
items stored, but also their relationship to each other.
List out the areas in which data structures are applied extensively?
Compiler Design,
Operating System,
Database Management System,
Statistical analysis package,
Numerical Analysis,
Graphics,
Artificial Intelligence,
Define variable and constant.
A variable can be defined as a meaningful name that is given to a data
storage location in the computer memory that contains a value.

What is a data type? How many types of data types are there in
.NET ?
A data type is a data storage format that can contain a specific type or range
of values.
Value type - Refers to the data type that contains the data
Reference type - Refers to a data type that can access data by reference
What is an identifier?
Identifiers are northing but names given to various entities uniquely
identified in a program
Programmers

cannot

develop

a

class

whose

name

is public,

because, public is a keyword used to specify the accessibility of data in
programs.
What is parameter
A parameter is a special kind of variable, which is used in a function to
provide a piece of information or input to a caller function. These inputs are
called arguments. In C#, the different types of parameters are as follows:
Value type - Refers that you do not need to provide any keyword with a
parameter.
Reference type - Refers that you need to mention the ref keyword with a
parameter.
Output type - Refers that you need to mention the out keyword with a
parameter.
Optional parameter - Refers to the new parameter introduced in C# 4.0. It
allows you to neglect the parameters that have some predefined default
values

What is the main difference between sub-procedure and function?
The sub-procedure is a block of multiple visual basic statements within Sub
and End Sub statements. It is used to perform certain tasks, such as
changing properties of objects, receiving or processing data, and displaying
an output. You can define a sub-procedure anywhere in a program, such as
in

modules,

structures,

and

classes.

We can also provide arguments in a sub-procedure; however, it does not
return

a

new

value.

The function is also a set of statements within the Function and End Function
statements. It is similar to sub-procedure and performs the same task. The
main difference between a function and a sub-procedure is that subprocedures do not return a value while functions do
What are main features of cloud services?
Some important features of the cloud service are given as follows:
Accessing and managing the commercial software.
Centralizing

the

activities

of

management

of

software

in

the

Web

environment.
Developing applications that are capable of managing several clients.
Centralizing the updating feature of software that eliminates the need of
downloading the upgrades.
What is cloud computing?
The cloud computing is the computing which is completely based on the
Internet. It can also be defined as the next stage in the evolution of the
Internet. The cloud computing uses the cloud (Internet) that provides the
way to deliver the services whenever and wherever the user of the cloud
needs. Companies use the cloud computing to fulfill the needs of their

customers, partners, and providers. The cloud computing includes vendors,
partners, and business leaders as the three major contributors. The vendors
are the one who provide applications and their related technology,
infrastructure, hardware, and integration.
What is a cloud?
A cloud is a combination of hardware, networks, storage, services, and
interfaces that helps in delivering computing as a service. It has broadly
three users which are end user, business management user, and cloud
service provider
What is a binary semaphore? What is its use?
A binary semaphore is one, which takes only 0 and 1 as values. They are
used to implement mutual exclusion and synchronize concurrent processes.
List the Coffman's conditions that lead to a deadlock.
Mutual Exclusion: Only one process may use a critical resource at a time.
Hold & Wait: A process may be allocated some resources while waiting for
others.
No Pre-emption: No resource can be forcible removed from a process
holding it.
Circular Wait: A closed chain of processes exist such that each process
holds at least one resource needed by another process in the chain.
Translation Lookaside Buffer (TLB)?
In a cached system, the base addresses of the last few referenced pages is
maintained in registers called the TLB that aids in faster lookup
What is the difference between a constructor and a method?

A constructor is a member function of a class that is used to create objects
of that class. It has the same name as the class itself, has no return type,
and is invoked using the new operator.
A method is an ordinary member function of a class. It has its own name, a
return type (which may be void), and is invoked using the dot operator.
What is the purpose of garbage collection in Java, and when is it
used?
The purpose of garbage collection is to identify and discard objects that are
no longer needed by a program so that their resources can be reclaimed and
reused.
. What is database?
A database is a logically coherent collection of data with some inherent
meaning, representing some aspect of real world and which is designed,
built and populated with data for a specific purpose.
2. What is DBMS?
It is a collection of programs that enables user to create and maintain a
database. In other words it is general-purpose software that provides the
users with the processes of defining, constructing and manipulating the
database for various applications.
3. What is a Database system?
The database and DBMS software together is called as Database system.
4. What are the advantages of DBMS?
Redundancy is controlled.
Unauthorised access is restricted.

Providing multiple user interfaces.
Enforcing integrity constraints.
Providing backup and recovery.
5. What are the disadvantage in File Processing System?
Data redundancy and inconsistency.
Difficult in accessing data.
Data isolation.
Data integrity.
Concurrent access is not possible.
Security Problems.
6. Describe the three levels of data abstraction?
The are three levels of abstraction:
Physical level: The lowest level of abstraction describes how data are
stored.
Logical level: The next higher level of abstraction, describes what data are
stored in database and what relationship among those data.
View level: The highest level of abstraction describes only part of entire
database.
Define the "integrity rules"?
There are two Integrity rules.
Entity Integrity: States that "Primary key cannot have NULL value"
Referential Integrity: States that "Foreign Key can be either a NULL value
or should be Primary Key value of other relation.
What is Data Independence?
Data independence means that "the application is independent of the
storage structure and access strategy of data". In other words, The ability to

modify the schema definition in one level should not affect the schema
definition

in

the

next

higher

level.

Two types of Data Independence:
Physical Data Independence: Modification in physical level should not
affect the logical level.
Logical Data Independence: Modification in logical level should affect the
view level.
NOTE: Logical Data Independence is more difficult to achieve
12. What is a view? How it is related to data independence?
A view may be thought of as a virtual table, that is, a table that does not
really exist in its own right but is instead derived from one or more
underlying base table. In other words, there is no stored file that direct
represents the view instead a definition of view is stored in data dictionary.
What is Data Model?
A collection of conceptual tools for describing data, data relationships data
semantics and constraints.
14. What is E-R model?
This data model is based on real world that consists of basic objects called
entities and of relationship among these objects. Entities are described in a
database by a set of attributes.
What is Weak Entity set?
An entity set may not have sufficient attributes to form a primary key, and
its primary key compromises of its partial key and primary key of its parent
entity, then it is said to be Weak Entity set.

21. What is an attribute?
It is a particular property, which describes the entity.
22. What is a Relation Schema and a Relation?
A relation Schema denoted by R(A1, A2, ..., An) is made up of the relation
name R and the list of attributes Ai that it contains. A relation is defined as a
set of tuples. Let r be the relation which contains set tuples (t1, t2, t3, ...,
tn). Each tuple is an ordered list of n-values t=(v1,v2, ..., vn).
23. What is degree of a Relation?
It is the number of attribute of its relation schema.
24. What is Relationship?
It is an association among two or more entities.
What is DDL (Data Definition Language)?
A data base schema is specifies by a set of definitions expressed by a special
language called DDL.
What is RDBMS?
Relational

Data

Base

Management

Systems

(RDBMS)

are

database

management systems that maintain data records and indices in tables
What is Enterprise Resource Planning (ERP), and what kind of a
database is used in an ERP application?
Enterprise Resource Planning (ERP) is an information system used in
manufacturing companies and includes sales, inventory, production planning,
purchasing and other business functions. An ERP system typically uses a
multiuser database.

3. What is a DBMS?
DBMS stands for Database Management System. A DBMS receives requests
from applications and translates those requests into actions on a specific
database. A DBMS processes SQL statements or uses other functionality to
create, process and administer databases.
Write an SQL SELECT statement to display all the columns of the
STUDENT table but only those rows where the Grade column is
greater than or equal to 90.
SELECT * FROM STUDENT WHERE Grade >= 90;
8. Name and briefly describe the five SQL built-in functions.
COUNT: computes the number of rows in a table. SUM: totals numeric
columns. AVG: computes the average value. MAX: obtains the maximum
value of a column in a table. MIN: obtains the minimum value of a column in
a table.
9. Write an SQL SELECT statement to count the number of rows in
STUDENT table and display the result with the label NumStudents.
SELECT COUNT(*) AS NumStudents FROM STUDENT;
What is a foreign key, and what is it used for?
A foreign key is used to establish relationships among relations in the
relational model. Technically, a foreign key is a column (or columns)
appearing in one relation that is (are) the primary key of another table.
What does it mean when we say that a relation is in Boyce-Codd
Normal Form (BCNF)?

A relation is in BCNF when every determinant in the relation is a candidate
key.
C++ can be considered as the Develop form of C.Its originated from
c and include the most important concept i.e. "Object Oriented".
The

Most

common

Difference

are

as

follow

:

1.C is Procedural Language and C++ is Procedural+Objected Oriented.
2.C

contains

3.Data

is

32
not

Keywords,C++
secured

in

C

extends
due

it
to

to

52

non-object

Keywords.
oriented.

4.C followe top down approach while C++ follow Bottomup approach.
5.We can use function inside structure in C++,but not in C.
Malloc and calloc
void

*malloc(size_t

size);

The function allocates an object of size_t size (size_t = int, char, float...etc),
and returns the address of the object if successful; otherwise, it returns a
null pointer. The values stored in the object are indeterminate. You can
safely convert the return value to an object pointer of any type whose size is
not
void

greater
*calloc(size_t

than
nelem,

size.
size_t

size);

The function allocates an array object containing nelem (number of
elements) each of size_t size, stores zeros in all bytes of the array, and
returns the address of the first element of the array if successful; otherwise,
it returns a null pointer. You can safely convert the return value to an object
pointer of any type whose size in bytes is not greater than size.

What does Candidate Key mean?
A candidate key is a column, or set of columns, in a table that can uniquely identify any
database record without referring to any other data. Each table may have one or more
candidate keys, but one candidate key is special, and it is called the primary key. This is
usually

the

best

among

the

candidate

keys.

When a key is composed of more than one column, it is termed a composite key
A superkey is a combination of attributes that can be uniquely used to identify a
database record. A table might have many superkeys
difference

between

macro

and

procedure

1) The invocation of macro in the program invokes the code in the program
with the codes defined in the program.Whereas when procedureis called it
sends the control to the starting address of the code defined in the
procedure and the code is invoked in the program.
2) There is branched execution in case of macro but there is sequential
execution

in

case

of procedure.

3) Macro does not make use of stack as the codes are defined in
a macro within the register and these codes are invoked with the help of
macro at different parts of the program wherever they are needed.In the
case of Procedure it makes use of stack may be the system stack or explicitly
defined stack.The registers are pushed onto the stack and are popped back
before

the

end

of

the

procedure.

4) Macro increases the length of the program if macro is invoked several
times within the program.But the procedure is called by pointing to the
address

in

5) Macro is

comparatively

and procedure is

the
faster

memory
slower
as

as
there

where procedure is
there
is

is

branched

sequential

stored.
execution
execution.

Macro and procedure both helps us in shortening our program,we have to
decide where we have to use macro and where we have to use procedure.

DATA STRUCTURES
1. What is data structure?
The logical and mathematical model of a particular
organization of data is called data structure.
There are two types of data structure
Linear
Nonlinear
2. What is a linked list?
A linked list is a linear collection of data elements,
called nodes, where the linear order is given by
pointers. Each node has two parts first part contain
the

information

of

the

element

second

part

contains the address of the next node in the list.
3. What is a queue?
A queue is an ordered collection of items from
which items may be deleted at one end (front end)
and items inserted at the other end (rear end). It
obeys FIFO rule there is no limit to the number of
elements a queue contains.
4. What is a spanning Tree?
A spanning tree is a tree associated with a
network. All the nodes of the graph appear on the
tree once. A minimum spanning tree is a spanning
tree organized so that the total edge weight
between nodes is minimized.
5. What is precision?

Precision refers the accuracy of the decimal portion
of a value. Precision is the number of digits allowed
after the decimal point.
6. What are the goals of Data Structure?
It must rich enough in structure to reflect the
actual relationship of data in real world. The
structure should be simple enough for efficient
7
.

processing of data.
What is the difference between a Stack and
an Array?
Stack



Stack is a dynamic object whose size is
constantly changing as items are pushed and
popped .



Stack may contain different data types.



Stack is declared as a structure containing
an array to hold the element of the stack, and an
integer to indicate the current stack top within
the array.



Stack is a ordered collection of items.
Array



Array is an ordered collection of items.



Array is a static object.



It contains same data types.



Array can be home of a stack i.e. array can
be declared large enough for maximum size of
the stack.

8. What is sequential search?
In sequential search each item in the array is

compared with the item being searched until a
match occurs. It is applicable to a table organized
either as an array or as a linked list.
9. What
are
the
disadvantages

array

implementations of linked list?
The no of nodes needed can’t be predicted when
the

program

is

written.

The no of nodes declared must remain allocated
throughout its execution.
10. What is a priority queue?
The priority queue is a data structure in which the
intrinsic ordering of the elements.
11. What are the disadvantages of sequential
storage?
Fixed amount of storage remains allocated to the
data structure even if it contains less element.
No more than fixed amount of storage is allocated
causing overflow.
12. Define circular list?
In linear list the next field of the last node contain
a null pointer, when a next field in the last node
contain a pointer back to the first node it is called
circular list.
13. What does abstract Data Type Mean?
Data type is a collection of values and a set of
operations on these values. Abstract data type
refer to the mathematical concept that define the
data type.
14. What do you mean by recursive definition?
The definition which defines an object in terms of
simpler cases of itself is called recursive definition.
15. What actions are performed when a function
is called?

When a function is called
arguments are passed
local variables are allocated and initialized
transferring control to the function
16. Define double linked list?
It is a collection of data elements called nodes,
where each node is divided into three parts
An info field that contains the information
stored in the node.
Left field that contain pointer to node on left
side.
Right field that contain pointer to node on
right side.
17. What

do

you

mean

by

overflow

and

underflow?
When new data is to be inserted into the data
structure but there is no available space i.e.free
storage list is empty this situation is called
overflow.
When we want to delete data from a data
structure that is empty this situation is called
underflow.
18. Whether Linked List is linear or Non-linear
data structure?
According to Access strategies Linked list is a
linear one. According to Storage Linked List is a
Non-linear one.

19. What do you mean by free pool?
Pool is a list consisting of unused memory cells
which has its own pointer.
20. What are the methods available in storing
sequential files ?
Straight merging
Natural merging
Polyphase sort
Distribution of Initial runs
21. What is a node class?
A node class is a class that has added new
services

or

functionality

beyond

the

services

inherited from its base class.
22. what is binary tree?
A binary tree is a tree data structure in which each
node

has

at

most

two

child

nodes,

usually

distinguished as left and right.

Database
1. Define SQL?
Structured query

language is

the

standard

command set used to communicate with the
relational database management system.
2. Define Dbms?
A Database Management system consists of a
collection of interrelated data and set of programs
to access that data.
3. What is the purpose of Database systems?
A Database Management system provides a secure
and

survivable

medium

for

the

storage

and

retrieval of data.In the real world, the data is
shared among several users and is persistent.
4. State the different between Security and

Integrity?
Security is a protection from malicious attempts to
steal

or

modify

Integrity constraints
damage

to

the

guard

database,

data.

against
by

accidental

ensuribg

that

authorized changes to the database do not result in
a loss of data consistency.
5. Define Normalisation?
Normalisation is an essential part of database
design. A good understanding of the semantic of
data helps the designer to built efficient design
using the concept of normalization.
6. What are the purpose of Normalisation?
Minimize redundancy in data.
Remove insert, delete and update anamoly
during the database activities.
Reduce the need to reorganize data it is
modified or enhanced.
7. Define Primary Key?
The primary key is the columns used to
uniquely identify each row of a table.
A table can have only one primary key.
No primary key value can appear in more
than one row in the table.
8. Define Unique Key?
Unique key is a one or more column that must be
unique

for

each

row

of

the

table.

It is similar to primary key. Primary key column will
not accept a null. Whereas the unique key column
will accept a null values.

9. Define Foreign Key?
A foreign Key is a combination of columns with
value is based on the primary key values from
another table. A foreign key constraint also known
as Referential Integrity Constraint.
10. Define View?
A View is a database object that is a logical
representation of a table.
It is derived from a table but has no longer
of its own and often may be used in the same
manner as a table.
A view is a virtual table that has columns
similar to a table.
A view does not represent any physical data.
11. Compare and contrast TRUNCATE and DELETE
for a table?
Both the truncate and delete command have the
desired outcome of getting rid of all the rows in a
table. The difference between the two is that the
truncate command is a DDL operation and just
moves the high water mark and produces a now
rollback. The delete command, on the other hand,
is a DML operation, which will produce a rollback
and thus take longer to complete.
12. What is cursors?
Cursor is a database object used by applications to
manipulate data in a set on a row-by-row basis,
instead of the typical SQL commands that operate
on all the rows in the set at one time.
13. Define SubQuery?

Nesting of Queries one within the other is
called as a Subquery.
A table can have only one primary key.
14. What are the different types of subquery?
Single row subquery
Multiple row subquery
Correlated row subquery
15. What are the different types of replication?
The SQL Server 2000-supported replication types
are as follows
Transactional
Snapshot
Merge
16. What is User Defined Functions?
User-Defined Functions allow to define its own TSQL

functions

that

can

accept

0

or

more

parameters and return a single scalar data value
or a table data type.
17. Define Self Join?
Self join means joining one table with itself.
The self join can be viewed as a join of two copies
of the same table.
18. Define Sequence?
A Sequence is a database object that can be used
to

provide

very

quick

generation

of

unique

numbers.
19. Define Joins?
A Join combines columns and data from two or
more tables (and in rare cases, of one table with

itself).
20. What are the types of Joins?
Equi joins
Cartesian Joins
Outer Joins
Self Joins.
21. Define Equi Joins?
A Equi Join is a join in which the join comparison
operator is an equality. When two tables are joined
together using equality or values in one or more
columns, they make an Equi Join.
22. Define Cartesian Join?
Joining two tables without a whereclause produces
a Cartesian join which combines every row in one
table with every row in another table.
23. What are three SQL keywords used to change
or set someone's permissions?
GRANT, DENY, and REVOKE
24. What are primary keys and foreign keys?
Primary keys are the unique identifiers for each
row. They must contain unique values and cannot
be null. Due to their importance in relational
databases, Primary keys are the most fundamental
of all keys and constraints. A table can have only
one

Primary

key.

Foreign keys are both a method of ensuring data
integrity and a manifestation of the relationship
between tables.
25. Define data model?
Underlying the structure of the database is called

as data model.
26. What is an Entity?
It is a 'thing' in the real world with an independent
existence.
27. What is BCP? When does it used?
BulkCopy is a tool used to copy huge amount of
data from tables and views. BCP does not copy the
structures same as source to destination.
28. Explain the use of the by GROUP BY and the
HAVING clause?
The GROUP BY partitions the selected rows on the
distinct values of the column on which the group
by

has

been

done.

The HAVING selects groups which match the
criteria specified.
29. What is DataWarehousing?
According to Bill Inmon, known as father of Data
warehousing. “A Data warehouse is a subject
oriented, integrated ,time variant, non volatile
collection of data in support of management’s
decision making process”.
30. What are the advantages of Database?
Redundancy can be reduced
Inconsistence can be avoided
The data can be shared
Standards can be enforced
Security can be enforced
Integrity can be maintained
31. What are the advantage of SQL?
The advantages of SQL are

SQL is a high level language that provides a
greater degree of abstraction than procedural
languages.
SQL enables the end users and system
personnel to deal with a number of Database
management systems where it is available.
Application written in SQL can be easily
ported across systems.
32. What is the difference between join and
outer join?
Outer joins return all rows from at least one of
the tables or views mentioned in the FROM clause,
as long as those rows meet any WHERE or HAVING
search

conditions.

A join combines columns and data from two are
more tables.
33. Define Boyce coded normal form?
A relation is said to be in Boyce coded normal form
if it is already in the third normal form and every
determine is a candidate key.
34. What are the transaction properties?
Atomicity
Consistency
Isolation
Durability
35. What is data mining?
Data mining refers to using variety of techniques
to identify nuggests of information or decision

making knowledge in bodies of data and extracting
these in such a way that they can be put in the
use

in

the

areas

such

as

decision

support,

predication, forecasting and estimation.
36. Compare DBMS versus object oriented DBMS?
DBMS consists of a collection of interrelated data
and a set of programs to access that data.
The object oriented DBMS is one of the type of
dbms in which information is stored in the form of
objects.
37. What are the types of SQL Commands?
Data Definition Language (DDL)
Data Manipulation Language (DML)
Data Query Language (DQL)
Data Control Language (DCL)
38. What is an attribute?
An entity is represented by a set of attributes.
Attributes are descriptive properties possessed by
each

member

of

an

entity

set.

There are different types of attributes.
Simple
Composite
Single-valued
Derived
39. What are the different types of data models ?
Entity relationship model
Relational model
Hierarchical model
Network model

Object oriented model
Object relational model
40. What is an active database?
Active database is a database that includes active
rules, mostly in the form of ECA rules(Event
Condition
Active

rules).

database

database

systems

functionality

enhance

with

traditional

powerful

rule

processing cabalities, providing a uniform and
efficient

mechanism

for

database

system

applications.
41. What are ACID properties?

Atomicity
Consistency
Isolation
Durability
42. Define Self Join?
Self join means joining one table with itself.
The self join can be viewed as a join of two copies
of the same table.
43. What is a tuple?
A tuple is an instance of data within a relational
database.
44. What is meant by embedded SQL?
They are SQL statements that are embedded with
in application program and are prepared during
the

program

preparation

process

before

the

program is executed. After it is prepared, the
statement itself does not change(although values

of host variables specified within the statement
might change).
45. What is Functional Dependency?
A Functional dependency is denoted by X Y
between two sets of attributes X and Y that are
subsets of R specifies a constraint on the possible
tuple that can form a relation state r of R. The
constraint is for any two tuples t1 and t2 in r if
t1[X] = t2[X] then they have t1[Y] = t2[Y]. This
means the value of X component of a tuple
uniquely determines the value of component Y.
46. What are the different phases of transaction?
The different phases of transaction are
Analysis phase
Redo Phase
Undo phase
47. What the difference between UNION and
UNIONALL?
Union will remove the duplicate rows from the
result set while Union all does’nt.
48. What is diffrence between Co-related sub
query and nested sub query?
Correlated subquery runs once for each row
selected

by

the

outer

query.

It

contains

a

reference to a value from the row selected by the
outer

query.

Nested subquery runs only once for the entire
nesting (outer) query. It does not contain any

reference to the outer query row.
49. What is the use of DBCC commands?
DBCC stands for database consistency checker. We
use these commands to check the consistency of
the databases, i.e., maintenance, validation task
and status checks.
50. What is a Linked Server?
Linked Servers is a concept in SQL Server by
which we can add other SQL Server to a Group
and query both the SQL Server dbs using T-SQL
Statements. With a linked server, you can create
very clean, easy to follow, SQL statements that
allow remote data to be retrieved, joined and
combined with local data.
51. What is Collation?
Collation refers to a set of rules that determine
how data is sorted and compared. Character data
is sorted using rules that define the correct
character sequence, with options for specifying
case-sensitivity, accent marks, kana character
types and character width.
52. What
are
different
type

of

Collation

Sensitivity?
The different phases of transaction are
Case sensitivity
Accent sensitivity
Kana Sensitivity
Width sensitivity
53. What is the difference between a primary key

and a unique key?
Both primary key and unique enforce uniqueness
of the column on which they are defined. But by
default primary key creates a clustered index on
the

column,

where

are

unique

creates

a

nonclustered index by default. Another major
difference is that, primary key doesn’t allow
NULLs, but unique key allows one NULL only.
54. What is the difference between Function and
Stored Procedure?
UDF can be used in the SQL statements
anywhere in the WHERE / HAVING / SELECT
section where as Stored procedures cannot be.
UDFs that return tables can be treated as
another rowset. This can be used in JOINs with
other tables.
Inline UDF’s can be though of as views that
take parameters and can be used in JOINs and
other Rowset operations.
55. What command do we use to rename a db?
sp_renamedb
“oldname”
,
“newname”
If

someone

is

using

db

it

will

not

accept

sp_renmaedb. In that case first bring db to single
user using sp_dboptions. Use sp_renamedb to
rename database.

Use sp_dboptions to bring

database to multi user mode.
56. What is BCP?
BulkCopy is a tool used to copy huge amount of
data from tables and views. BCP does not copy the
structures same as source to destination.

57. What is Cross Join?
A cross join that does not have a WHERE clause
produces the Cartesian product of the tables
involved in the join. The size of a Cartesian
product result set is the number of rows in the first
table multiplied by the number of rows in the
second table.
58. What is Storage Manager?
It is a program module that provides the interface
between the low-level data stored in database,
application programs and queries submitted to the
system.
59. What are stored-procedures? And what are
the advantages of using them?
Stored procedures are database
perform

a

user

defined

objects

operation.

A

that

stored

procedure can have a set of compound SQL
statements. A stored procedure executes the SQL
commands and returns the result to the client.
Stored procedures are used to reduce network
traffic.
60. What is database Trigger?
A database trigger is a PL/SQL block that can
defined

to

automatically

execute

for

insert,

update, and delete statements against a table. The
trigger can e defined to execute once for the entire
statement or once for every row that is inserted,
updated, or deleted.
61. What is OLTP?
Online Transaction Processing (OLTP) relational
databases are optimal for managing changing
data.

When

several

users

are

performing

transactions at the same time, OLTP databases are
designed to let transactional applications write
only

the

data

needed

to

handle

a

single

transaction as quickly as possible.
62. What is DDL (Data Definition Language)?
A data base schema is specifies by a set of
definitions expressed by a special language called
DDL.
63. What is Weak Entity set?
An entity set may not have sufficient attributes to
form

a

primary

key,

and

its

primary

key

compromises of its partial key and primary key of
its parent entity, then it is said to be Weak Entity
set.
64. What is a deadlock?
Two processes wating to update the rows of a
table which are locked by the other process then
deadlock arises.
65. What do you mean by flat file database?
It is a database in which there are no programs or
user

access

languages.

It

has

no

cross-file

capabilities but is user-friendly and provides userinterface management.
66. What is Storage Manager?
It is a program module that provides the interface
between the low-level data stored in database,
application programs and queries submitted to the
system.
67. What is Index?
An index is a physical structure containing pointers
to the data. Indices are created in an existing
table to locate rows more quickly and efficiently. It

is possible to create an index on one or more
columns of a table, and each index is given a
name.
68. What is the difference between clustered and
a non-clustered index?
A Clustered index is a special type of index that
reorders

the

way

records

in

the

table

are

physically stored. Therefore table can have only
one clustered index. The leaf nodes of a clustered
index

contain

the

data

pages.

A Nonclustered index is a special type of index in
which the logical order of the index does not
match the physical stored order of the rows on
disk. The leaf node of a nonclustered index does
not consist of the data pages. Instead, the leaf
nodes contain index rows.
69. What is the difference between a HAVING
CLAUSE and a WHERE CLAUSE?
HAVING can be used only with the SELECT
statement. HAVING is typically used in a GROUP
BY clause. When GROUP BY is not used, HAVING
behaves like a WHERE clause. Having Clause is
basically used only with the GROUP BY function in
a query. WHERE Clause is applied to each row
before they are part of the GROUP BY function in a
query.
70. What is log shipping?
Log shipping is the process of automating the
backup of database and transaction log files on a

production SQL server, and then restoring them
onto a standby server. Enterprise Editions only
supports

log

transactional

shipping.
log

file

In
from

log

shipping

one

server

the
is

automatically updated into the backup database
on the other server.
71. What are primary keys and foreign keys?
Primary keys are the unique identifiers for each
row. They must contain unique values and cannot
be null. Due to their importance in relational
databases, Primary keys are the most fundamental
of all keys and constraints. A table can have only
one

Primary

key.

Foreign keys are both a method of ensuring data
integrity and a manifestation of the relationship
between tables.
72. What are check constraint?
A Check constraint is used to limit the values
that can be placed in a column. The check
constraints are used to enforce domain integrity.
96. What is Self Join?
A self join can be of any type, as long as the
joined tables are the same. A self join is rather
unique in that it involves a relationship with only
one table.
73. What are the type of Synonyms?
There are two types of Synonyms are :
Private
Public
74. What is an Integrity Constrains?
An integrity constraint is a declarative way to

define a business rule for a column of a table.
75. What is Table?
A table is the basic unit of data storage in an
ORACLE database. The tables of a database hold
all of the user accessible data. Table data is stored
in rows and columns.
76. What is a synonym?
A synonym is an alias for a table, view, sequence
or program unit.
77. What is Rollback Segment?
A Database contains one or

more

Rollback

Segments to temporarily store "undo" information.
78. What does COMMIT do?
A Commit makes
permanent
the
changes
resulting

from

transaction.

The

all

SQL

changes

statements
made

by

in

the

the

SQL

statements of a transaction become visible to
other user sessions transactions that start only
after transaction is committed.
79. What is a Database instance?
A database instance (Server) is a set of memory
structure and background processes that access a
set of database files.
80. What are Roles?
Roles are named groups of related privileges that
are granted to users or other roles.
81. What is SQLPlus?
SQLPlus is an application that recognizes

&

executes SQL commands & specialized SQL*Plus
commands that can customize reports, provide
help & edit facility & maintain system variables.
82. What is the difference between normalization
and denormalization?
Normalizing data means eliminating redundant

information from a table and organizing the data
so that future changes to the table are easier.
Denormalization means allowing redundancy in a
table. The main benefit of denormalization is
improved

performance

with

simplified

data

retrieval and manipulation.
83. What is a trigger?
Triggers are stored procedures created in order to
enforce integrity rules in a database. A trigger is
executed every time a data-modification operation
occurs

(i.e.,

insert,

update

or

delete).

Triggers are executed automatically on occurance
of one of the data-modification operations.
84. What is the difference between static and
dynamic SQL?
Static SQL is hard-coded in a program when the
programmer

knows

the

statements

to

be

executed.
Dynamic

SQL the

program

must

dynamically

allocate memory to receive the query results.
85. What is UNIQUE KEY constraint?
A UNIQUE constraint enforces the uniqueness of
the values in a set of columns, so no duplicate
values are entered. The unique key constraints are
used to enforce entity integrity as the primary key
constraints.
86. What is NOT NULL Constraint?
A NOT NULL constraint enforces that the column
will not accept null values. The not null constraints
are used to enforce domain integrity, as the check
constraints.

87. What is meant by query optimization?
The phase that identifies an efficient execution
plan for evaluating a query that has the least
estimated

cost

is

referred

to

as

query

optimization.
88. What is meant by embedded SQL?
They are SQL statements that are embedded with
in application program and are prepared during
the

program

preparation

process

before

the

program is executed.
89. What is File Manager?
It is a program module, which manages the
allocation of space on disk storage and data
structure used to represent information stored on
a disk.
90. Define transaction?
A collection of operations that fom a single logical
unit of works are called transaction.
91. Define Constraints?
Constraints is a rule or restriction concerning a
piece of data that is enforced at the data level.
A Constraint clause can constrain a single column
or

group

of

columns

in

a

table.

There are five types of Constraint namely
Null / Not Null
Primary Key
Unique
Check or Validation
Foreign Key or References Key
92. What are types of sub-queries?
Single-row subquery, where the subquery

returns only one row.
Multiple-row subquery, where the subquery
returns multiple rows.
Multiple

column

subquery,

where

the

subquery returns multiple columns.
93. What is SQL Profiler?
SQL Profiler is a graphical tool that allows system
administrators to monitor events in an instance of
Microsoft SQL Server. You can capture and save
data about each event to a file or SQL Server table
to analyze later.
94. Define Clusters?
Clustering is a method of storing tables that are
intimately related and often joined together into
the

same

area

on

disk.

A cluster contains one or more tables, which have
one or more column in common among them.
95. Define Indexes?
Index is a general term for an Oracle/SQL features
used to primarily to speed execution and imposes
uniqueness

upon

certain

data.

The most important of an index is to ensure
uniqueness of rows and help in speedy retrieval of
data.
96. What is data integrity?
Data integrity is an important feature in SQL
Server. When used properly, it ensures that data is
accurate, correct, and valid. It also acts as a trap
for

otherwise

undetectable

bugs

within

applications.
97. What is De-normalization?
De-normalization is the process of attempting to

optimize the performance of a database by adding
redundant

data.

De-normalization is a technique to move from
higher

to

lower

normal

forms

of

database

modeling in order to speed up database access.
98. What is referential integrity?
Referential integrity refers to the consistency that
must be maintained between primary and foreign
keys, i.e. every foreign key value must have a
corresponding primary key value.
99. What is the difference between static and
dynamic SQL?
Static SQL is hard-coded in a program when the
programmer

knows

the

statements

to

be

executed.
For dynamic SQL the program must dynamically
allocate memory to receive the query results.
100. Define Unique Key?
Unique key is a one or more column that must be
unique

for

each

row

of

the

table.

It is similar to primary key. Primary key column
will not accept a null. Whereas the unique key
column will accept a null values.
101. Define Synonym?
Synonym is an alternative method to creating a
view that includes the entire table or view from
another

user

it

to

create

a

synonym.

A synonym is a name assigned to a table or view
that may thereafter be used to refer to it.
102. What is an Data Abtration?
A major purpose of a database system is to
provide users with an abstract view of the

data.There are three levels of data abstraction
Physical level
Logical level
View level
103. What is Transaction Manager?
It is a program module, which ensures that
database, remains in a consistent state despite
system

failures

and

concurrent

transaction

execution proceeds without conflicting.
104. What kind of User-Defined Functions can be
created?
There are three types of User-Defined functions
in SQL Server 2000 and they are Scalar, Inline
Table-Valued and Multi-statement Table-valued.
105. What are defaults? Is there a column to
which a default can't be bound?
A default is a value that will be used by a
column, if no value is supplied to that column
while inserting data. IDENTITY columns and
timestamp columns can't have defaults bound to
them. See CREATE DEFUALT in books online.

DBMS
QUESTION
1: What is database?
ANSWER:
A database is a logically coherent collection of data with some inherent meaning,

representing some aspect of real world and which is designed, built and populated with
data for a specific purpose.
QUESTION 2: What is DBMS?
ANSWER:
? Redundancy is controlled.
? Unauthorized access is restricted.
? Providing multiple user interfaces.
? Enforcing integrity constraints.
? Providing backup and recovery.
QUESTION 3: What is a Database system?
ANSWER:
The database and DBMS software together is called as Database system.
QUESTION 4: Disadvantage in File Processing System?
ANSWER:
? Data redundancy & inconsistency.
? Difficult in accessing data.
? Data isolation.
? Data integrity.
? Concurrent access is not possible.
? Security Problems. .
QUESTION 5: Describe the three levels of data abstraction?

ANSWER:
The are three levels of abstraction:
? Physical level: The lowest level of abstraction describes how data are stored.
? Logical level: The next higher level of abstraction, describes what data are stored
in database and what relationship among those data.
? View level: The highest level of abstraction describes only part of entire database.
QUESTION 6: Define the "integrity rules"
ANSWER:
There are two Integrity rules.
? Entity Integrity: States that ?Primary key cannot have NULL value?
? Referential Integrity: States that ?Foreign Key can be either a NULL value or should
be Primary Key value of other relation.
QUESTION 7: What is extension and intension?
ANSWER:
Extension -It is the number of tuples present in a table at any instance. This is time
dependent.
Intension – It is a constant value that gives the name, structure of table and the
constraints laid on it.
QUESTION 8: What is System R? What are its two major subsystems?

ANSWER:
System R was designed and developed over a period of 1974-79 at IBM San Jose
Research Center . It is a prototype and its purpose was to demonstrate that it is possible
to build a Relational System that can be used in a real life environment to solve real life
problems, with performance at least comparable to that of existing system.
Its two subsystems are
? Research Storage
? System Relational Data System.
QUESTION 10: How is the data structure of System R different from the relational
structure?
ANSWER:
Unlike Relational systems in System R
? Domains are not supported
? Enforcement of candidate key uniqueness is optional
? Enforcement of entity integrity is optional
? Referential integrity is not enforced
QUESTION 11: What is Data Independence?
ANSWER:
Data independence means that ?the application is independent of the storage structure

and access strategy of data?. In other words, The ability to modify the schema definition
in one level should not affect the schema definition in the next higher level.
Two

types

of

Data

Independence:

? Physical Data Independence : Modification in physical level should not affect the
logical

level.

? Logical Data Independence : Modification in logical level should affect the view level.
NOTE: Logical Data Independence is more difficult to achieve
QUESTION 12: What is a view? How it is related to data independence?
ANSWER:
A view may be thought of as a virtual table, that is, a table that does not really exist in its
own right but is instead derived from one or more underlying base table. In other words,
there is no stored file that direct represents the view instead a definition of view is stored
in

data

dictionary.

Growth and restructuring of base tables is not reflected in views. Thus the view can
insulate users from the effects of restructuring and growth in the database. Hence
accounts for logical data independence. .
QUESTION 13: What is Data Model?
ANSWER:
A collection of conceptual tools for describing data, data relationships data semantics
and constraints.
QUESTION 14: What is E-R model?

ANSWER:
This data model is based on real world that consists of basic objects called entities and
of relationship among these objects. Entities are described in a database by a set of
attributes.
QUESTION 15: What is Object Oriented model?
ANSWER:
This model is based on collection of objects. An object contains values stored in
instance variables with in the object. An object also contains bodies of code that operate
on the object. These bodies of code are called methods. Objects that contain same
types of values and the same methods are grouped together into classes.
QUESTION 16: What is an Entity?
ANSWER:
It is a ‘thing’ in the real world with an independent existence.
QUESTION 17: What is an Entity type?
ANSWER:
It is a collection (set) of entities that have same attributes.
QUESTION 18: What is an Entity set?
ANSWER:
It is a collection of all entities of particular entity type in the database.
QUESTION 19: What is an Extension of entity type?

ANSWER:
The collections of entities of a particular entity type are grouped together into an entity
set.
QUESTION 20: What is Weak Entity set?
ANSWER:
An entity set may not have sufficient attributes to form a primary key, and its primary key
compromises of its partial key and primary key of its parent entity, then it is said to be
Weak Entity set.
QUESTION 21: What is an attribute?
ANSWER:
It is a particular property, which describes the entity.
QUESTION 22: What is a Relation Schema and a Relation?
ANSWER:
A relation Schema denoted by R(A1, A2, ?, An) is made up of the relation name R and
the list of attributes Ai that it contains. A relation is defined as a set of tuples. Let r be
the relation which contains set tuples (t1, t2, t3, …, tn). Each tuple is an ordered list of nvalues t=(v1,v2, …, vn).
QUESTION 23: What is degree of a Relation?
ANSWER:
It is the number of attribute of its relation schema.

QUESTION 24: What is Relationship?
ANSWER:
It is an association among two or more entities.
QUESTION 25: What is Relationship set?
ANSWER:
The collection (or set) of similar relationships.
QUESTION 26: What is Relationship type?
ANSWER:
Relationship type defines a set of associations or a relationship set among a given set
of entity types.
QUESTION 27: What is degree of Relationship type?
ANSWER:
It is the number of entity type participating.
QUESTION 28: What is Data Storage – Definition Language?
ANSWER:
The storage structures and access methods used by database system are specified by
a set of definition in a special type of DDL called data storage-definition language.
QUESTION 29: What is DML (Data Manipulation Language)?

ANSWER:
This language that enable user to access or manipulate data as organised by
appropriate data model.
? Procedural DML or Low level: DML requires a user to specify what data are needed
and how to get those data.
? Non-Procedural DML or High level: DML requires a user to specify what data are
needed without specifying how to get those data.
QUESTION 30: What is VDL (View Definition Language)?
ANSWER:
It specifies user views and their mappings to the conceptual schema.
QUESTION 31: What is DML Compiler?
ANSWER:
It translates DML statements in a query language into low-level instruction that the
query evaluation engine can understand.
QUESTION 32: What is Query evaluation engine?
ANSWER:
It executes low-level instruction generated by compiler.
QUESTION 33: What is DDL Interpreter?
ANSWER:
It interprets DDL statements and record them in tables containing metadata.

QUESTION 34: What is Record-at-a-time?
ANSWER:
The Low level or Procedural DML can specify and retrieve each record from a set of
records. This retrieve of a record is said to be Record-at-a-time.
QUESTION 35: What is Set-at-a-time or Set-oriented?
ANSWER:
The High level or Non-procedural DML can specify and retrieve many records in a single
DML statement. This retrieve of a record is said to be Set-at-a-time or Set-oriented.
QUESTION 36: What is Relational Algebra?
ANSWER:
It is procedural query language. It consists of a set of operations that take one or two
relations as input and produce a new relation.
QUESTION 37: What is Relational Calculus?
ANSWER:
It is an applied predicate calculus specifically tailored for relational databases proposed
by E.F. Codd. E.g. of languages based on it are DSL ALPHA, QUEL.
QUESTION 38: How does Tuple-oriented relational calculus differ from domain-oriented
relational calculus

ANSWER:
The tuple-oriented calculus uses a tuple variables i.e., variable whose only permitted
values are tuples of that relation. E.g. QUEL
The domain-oriented calculus has domain variables i.e., variables that range over the
underlying domains instead of over relation. E.g. ILL, DEDUCE.
QUESTION 39: What is normalization?
ANSWER:
It is a process of analysing the given relation schemas based on their Functional
Dependencies (FDs) and primary key to achieve the properties
? Minimizing redundancy
? Minimizing insertion, deletion and update anomalies.
QUESTION 40: What is Functional Dependency?
ANSWER:
A Functional dependency is denoted by X Y between two sets of attributes X and Y that
are subsets of R specifies a constraint on the possible tuple that can form a relation
state r of R. The constraint is for any two tuples t1 and t2 in r if t1[X] = t2[X] then they
have t1[Y] = t2[Y]. This means the value of X component of a tuple uniquely determines
the value of component Y.
QUESTION 41: When is a functional dependency F said to be minimal?

ANSWER:
? Every dependency in F has a single attribute for its right hand side.
? We cannot replace any dependency X A in F with a dependency Y A where Y is a
proper subset of X and still have a set of dependency that is equivalent to F.
? We cannot remove any dependency from F and still have set of dependency that is
equivalent to F.
QUESTION 42: What is Multivalued dependency?
ANSWER:
Multivalued dependency denoted by X Y specified on relation schema R, where X and Y
are both subsets of R, specifies the following constraint on any relation r of R: if two
tuples t1 and t2 exist in r such that t1[X] = t2[X] then t3 and t4 should also exist in r with
the following properties
? t3[x] = t4[X] = t1[X] = t2[X]
? t3[Y] = t1[Y] and t4[Y] = t2[Y]
? t3[Z] = t2[Z] and t4[Z] = t1[Z]
where [Z = (R-(X U Y)) ]
QUESTION 43: What is Lossless join property?
ANSWER:
It guarantees that the spurious tuple generation does not occur with respect to relation
schemas after decomposition.

QUESTION 44: What is 1 NF (Normal Form)?
ANSWER:
The domain of attribute must include only atomic (simple, indivisible) values.
QUESTION 45: What is Fully Functional dependency?
ANSWER:
It is based on concept of full functional dependency. A functional dependency X Y is full
functional dependency if removal of any attribute A from X means that the dependency
does not hold any more.
QUESTION 46: What is 2NF?
ANSWER:
A relation schema R is in 2NF if it is in 1NF and every non-prime attribute A in R is fully
functionally dependent on primary key.
QUESTION 47: What is 3NF?
ANSWER:
A relation schema R is in 3NF if it is in 2NF and for every FD X A either of the following
is true
? X is a Super-key of R.
? A is a prime attribute of R.
In other words, if every non prime attribute is non-transitively dependent on primary key.

QUESTION 48: What is BCNF (Boyce-Codd Normal Form)?
ANSWER:
A relation schema R is in BCNF if it is in 3NF and satisfies an additional constraint that
for every FD X A, X must be a candidate key.
QUESTION 49: What is 4NF?
ANSWER:
A relation schema R is said to be in 4NF if for every Multivalued dependency X Y that
holds over R, one of following is true
? X is subset or equal to (or) XY = R.
? X is a super key.
QUESTION 50: What is 5NF?
ANSWER:
A Relation schema R is said to be 5NF if for every join dependency {R1, R2, …, Rn}
that holds R, one the following is true
? Ri = R for some i.
? The join dependency is implied by the set of FD, over R in which the left side is key of
R.

OPERATING SYSTEM

1) Explain the main purpose of an operating system?
Operating systems exist for two main purposes. One is that it is designed to make sure
a computer system performs well by managing its computational activities. Another is
that it provides an environment for the development and execution of programs.
2) What is demand paging?
Demand paging is a system wherein area of memory that are not currently being used
are swapped to disk to make room for an application’s need.
3) What are the advantages of a multiprocessor system?
With an increased number of processors, there is considerable increase in throughput.
It can also save more money because they can share resources. Finally, overall
reliability is increased as well.
4) What is kernel?
Kernel is the core of every operating system. It connects applications to the actual
processing of data. It also manages all communications between software and
hardware components to ensure usability and reliability.
5) What are real-time systems?
Real-time systems are used when rigid time requirements have been placed on the
operation of a processor. It has well defined and fixed time constraints.
6) What is virtual memory?
Virtual memory is a memory management technique for letting processes execute
outside of memory. This is very useful especially is an executing program cannot fit in
the physical memory.
7) Describe the objective of multiprogramming.
The main objective of multiprogramming is to have process running at all times. With
this design, CPU utilization is said to be maximized.
8 ) What are time sharing systems?
In a Time sharing system, the CPU executes multiple jobs by switching among them,
also known as multitasking. This process happens so fast that users can actually
interact with each program while it is running.
9) What is SMP?

SMP is short for Symmetric MultiProcessing, and is the most common type of multipleprocessor systems. In this system, each processor runs an identical copy of the
operating system, and these copies communicate with one another as needed.
10) How are server systems classified?
Server systems can be classified as either computer-server systems or file server
systems. In the first case, an interface is made available for clients to send requests to
perform an action. In the second case, provisions are available for clients to create,
access and update files.
11) What is asymmetric clustering?
In asymmetric clustering, a machine is in a state known as hot standby mode where it
does nothing but to monitor the active server. That machine takes the active server’s
role should the server fails.
12) What is a thread?
A thread is a basic unit of CPU utilization. In general, a thread is composed of a thread
ID, program counter, register set and the stack.
13) Give some benefits of multithreaded programming.
-

there

is

an

resource

increased
sharing

-

responsiveness
within

to
the

the

user
process
economy

- utilization of multiprocessing architecture
14) Briefly explain FCFS.
FCFS is short for First-come, first-served, and is one type of scheduling algorithm. In
this scheme, the process that requests the CPU first is allocated the CPU first.
Implementation is managed by a FIFO queue.
15) What is RR scheduling algorithm?
RR (round-robin) scheduling algorithm is primarily aimed for time-sharing systems. A
circular queue is setup in such a way that the CPU scheduler goes around that queue,
allocating CPU to each process for a time interval of up to around 10 to 100
milliseconds.
16) What necessary conditions can lead to a deadlock situation in a system?

Deadlock situations occur when four conditions occur simultaneously in a system:
Mutual exclusion; Hold and Wait; No preemption; and Circular wait.
17) Enumerate the different RAID levels.
RAID

0

RAID
RAID

1
2

RAID



striping

Mirrored

Disks

error-correcting

codes

Memory-style


4
5

Non-redundant


3

RAID
RAID






Bit-interleaved
Block-interleaved

Block-interleaved

distributed

Parity
Parity
Parity

RAID 6 – P+Q Redundancy
18) Describe Banker’s algorithm

Bankers Algorithm
Banker’s algorithm is one form of deadlock-avoidance in a system. It gets its name from
a banking system wherein the bank never allocates available cash in such a way that it
can no longer satisfy the needs of all of its customers.
19) What factors determine whether a detection-algorithm must be utilized in a
deadlock avoidance system?
One is that it depends on how often a deadlock is likely to occur under the
implementation of this algorithm. The other has to do with how many processes will be
affected by deadlock when this algorithm is applied.
20) Differentiate logical from physical address space.

Logical address refers to the address that is generated by the CPU I thinks . On the
other hand, physical address refers to the address that is seen by the memory unit.
21) How does dynamic loading aid in better memory space utilization?
With dynamic loading, a routine is not loaded until it is called. This method is especially
useful when large amounts of code are needed in order to handle infrequently occurring
cases such as error routines.
22) What are overlays?
Overlays are used to enable a process to be larger than the amount of memory
allocated to it. The basic idea of this is that only instructions and data that are needed at
any given time are kept in memory.
23) What is the basic function of paging?
Paging is a memory management scheme that permits the physical-address space of a
process to be noncontiguous. It avoids the considerable problem of having to fit varied
sized memory chunks onto the backing store.
24) What is fragmentation?
Fragmentation is memory wasted. It can be internal if we are dealing with systems that
have fixed-sized allocation units, or external if we are dealing with systems that have
variable-sized allocation units.
25) How does swapping result in better memory management?
During regular intervals that are set by the operating system, processes can be copied
from main memory to a backing store, and then copied back later. Swapping allows
more processes to be run that can fit into memory at one time.
26) Give an example of a Process State.
-

New
Running

State




means
means

a

process

instructions

is
are

being
being

created
executed

- Waiting – means a process is waiting for certain conditions or events to occur
- Ready – means a process is waiting for an instruction from the main processor
- Terminate – means a process is done executing
27) What is a socket?
A socket provides a connection between two applications. Each endpoint of a
communication is a socket.

28) What is Direct Access Method?
Direct Access method is based on a disk model of a file, such that it is viewed as a
numbered sequence of blocks or records. It allows arbitrary blocks to be read or written.
Direct access is advantageous when accessing large amounts of information.
29) When does trashing occur?
Trashing refers to an instance of high paging activity. This happens when it is spending
more time paging instead of executing.
30) What is the best page size when designing an operating system?
The best paging size varies from system to system, so there is no single best when it
comes to page size. There are different factors to consider in order to come up with a
suitable page size, such as page table, paging time, and its effect on the overall
efficiency of the operating system.
31) When designing the file structure for an operating system, what attributes are
considered?
Typically, the different attributes for a file structure are naming, identifier, supported file
types, and location for the files, size, and level of protection.
32) What is root partition?
Root partition is where the operating system kernel is located. It also contains other
potentially important system files that are mounted during boot time.
33) What are device drivers?
Device drivers provides a standard means of representing I/O devices that maybe
manufactured by different companies. This prevents conflicts whenever such devices
are incorporated in a systems unit.
34) What are the primary functions of VFS?
VFS, or Virtual File System, separates file system generic operations from their
implementation by defining a clean VFS interface. It is also based on a filerepresentation structure known as vnode, which contains a numerical designator
needed to support network file systems.
35) What are the different types of CPU registers in a typical operating system
design?

-

Accumulators
Index
Stack

Registers
Pointer

- General Purpose Registers
36) What is the purpose of an I/O status information?
I/O status information provides info about which I/O devices are to be allocated for a
particular process. It also shows which files are opened, and other I/O device state.
37) What is multitasking?
Multitasking is the process within an operating system that allows the user to run
several applications at the same time. However, only one application is active at a time
for user interaction, although some applications can run “behind the scene”.
38) What are some pros and cons of a command line interface?
A command line interface allows the user to type in commands that can immediately
provide results. Many seasoned computer users are well accustomed to using the
command line because they find it quicker and simpler. The main problem with a
command line interface is that users have to be familiar with the commands, including
the switches and parameters that come with it. This is a downside for people who are
not fond of memorizing commands.
39) What is caching?
Caching is the processing of utilizing a region of fast memory for a limited data and
process. A cache memory is usually much efficient because of its high access speed.
40) What is spooling?
Spooling is normally associated with printing. When different applications want to send
an output to the printer at the same time, spooling takes all of these print jobs into a disk
file and queues them accordingly to the printer.
41) What is an Assembler?
An assembler acts as a translator for low level language. Assembly codes, written using
mnemonic commands are translated by the Assembler into machine language.
42) What are interrupts?

Interrupts are part of a hardware mechanism that sends a notification to the CPU when
it wants to gain access to a particular resource. An interrupt handler receives this
interrupt signal and “tells” the processor to take action based on the interrupt request.
43) What is GUI?
GUI is short for Graphical User Interface. It provides users with an interface wherein
actions can be performed by interacting with icons and graphical symbols. People find it
easier to interact with the computer when in a GUI especially when using the mouse.
Instead of having to remember and type commands, users just click on buttons to
perform a process.
44) What is preemptive multitasking?
Preemptive multitasking allows an operating system to switch between software
programs. This in turn allows multiple programs to run without necessarily taking
complete control over the processor and resulting in system crashes.
45) Why is partitioning and formatting a prerequisite to installing an operating
system?
Partitioning and formatting creates a preparatory environment on the drive so that the
operating system can be copied and installed properly. This includes allocating space
on the drive, designating a drive name, determining and creating the appropriate file
system structure.
46) What is plumbing / piping?
It is the process of using the output of one program as an input to another. For example,
instead of sending the listing of a folder or drive to the main screen, it can be piped and
sent to a file, or sent to the printer to produce a hard copy.
47) What is NOS?
NOS is short for Network Operating System. It is a specialized software that will allow a
computer to communicate with other devices over the network, including file/folder
sharing.
48) Differentiate internal commands from external commands.
Internal commands are built-in commands that are already part of the operating system.
External commands are separate file programs that are stored in a separate folder or
directory.

49) Under DOS, what command will you type when you want to list down the files
in a directory, and at the same time pause after every screen output?
a)

dir

/w

b)

dir

/p

c)

dir

/s

d) dir /w /p
Answer: d) dir /w /p
50) How would a filenamed EXAMPLEFILE.TXT appear when viewed under the
DOS command console operating in Windows 98?
The filename would appear as EXAMPL~1.TXT . The reason behind this is that
filenames under this operating system is limited to 8 characters when working under
DOS environment.

SOFTWARE ENGINEERING
1. Define software engineering?
According to IEEE, Software engineering is the
application of a systematic, disciplined, quantifiable
approach

to

the

development,

operation

and

maintenance of sofware.
2. What are the categories of software?
System software
Application software
Embedded software
Web Applications
Artificial Intelligence software
Scientific software.
3. Define testing?
Testing is a process of executing a program with
the intent of finding of an error.
4. What is white box testing?

White box testing is a test case design method that
uses the control structure of the procedural design
to

derive

test

cases.

It

is

otherwise

called

as structural testing.
5. What is Black box testing?
Black box testing is a test case design method that
focuses on the functional requirements of the
software.

It is otherwise called as functional

testing.
6. What is verification and validation?
Verification refers to the set of activities that
ensure

that

software

correctly

implements

specific

a

function.

Validation refers to the set of activities that
ensure that the software that has been built is
traceable to customer requirements.
7. What is debugging?
Debugging is the process that results in the
removal of error. It occurs as a consequence of
successful testing.
8. Define cyclomatic complexity?
Cyclomatic complexity is a software metric that
provides a quantitative measuer of the logical
complexity of a program.
9. What is error tracking?
Error tracking is an activity that provides a means
for assessing the status of a current project.
10. What are case tools?
Computer Aided Software Engineering - CASE tools
assist

software

engineering

managers

and

practitioners in evey activity associated with the
software

process.

They

automate

project

management activities manage all work products
produced throughout the process and assist the
engineers in their analysis, design, coding and test
work.
12345678910
11. What is data design?
Data design transforms the information domain
model

created

during

analysis

into

the

data

structures that will be required to implement the
software.
12. Define cohension and coupling?
Cohension is a measure of the relative functional
strength
Coupling is

of
a

measure

a
of

module.
the

relative

interdependence among modules.
13. What are the different types of cohension?
There are different types of cohension are
Coincidental cohension
Logical cohension
Temporal cohension
Procedural cohension
Communicational cohension
14. What are the different types of coupling?
There are different types of coupling are
Data coupling
Stamp coupling
Control coupling

External coupling
Common coupling
Content coupling
15. What is user interface design?
User interface design creates

an

effective

communication medium between a human and a
computer.
16. What is meant by specification?
A specification can be a written document, a
graphical model, a formal mathematical model, a
collection of usage scenarios, a prototype or any
combination of these.
17. Define process?
A series of steps involving activities, constraints,
and resources that produce an intended output of
some kind is known as process.
18. How spiral model works?
The spiral model is an evolutionary software
process model that couples the iterative nature of
prototyping with the controlled and systematic
aspects of the waterfall lifecycle model. It also has
an emphasis on the use of risk management
techniques.
19. What is winwin spiral model?
Winwin spiral model defines a set of negotiation
activities at the beginning of each pass around the
spiral. The best negotiations strive for a win-win
result.
20. Mention

the

various

views

in

system

engineering hierarchy?
The various views in system engineering hierarchy
from top to bottom in order are

World view
Domain view
Element view
Detailed view
21. What is software requirements definition?
A software requirements definition is an abstract
description of the services which the system
should provide and the constraints under which
the system must operate.
22. What is SDLC ?
A software cycle deals with various parts and
phases from planning to testing and deploying. All
these activities are carried out in different ways,
as per the needs. Each way is known as a
Software Development Lifecycle Model (SDLC).
23. What are data aquistion systems?
Systems that collects data from sensors for
subsequent processing and analysis are termed as
Data acquistion systems. Data collection process
and processing processes may have different
periods and deadlines.
24. Define software configuration model?
SCM is the art of identifying, organizing, and
controlling modifications to the software being
built by a programming team. It is an umbrella
activity that is applied throughout the software
process.
25. What are the SCM activities?
SCM activities are developed to
Identify change

Control change
Ensure

that

change

is

being

properly

implemented
Report changes to others who may have an
interest.
26. What are the advantages and disadvantages
of white box testing?
Advantages
Software’s

structure

:
logic

can

be

tested.

Disadvantages

:

Doesn’t ensure that user requirements are met.
Its test may not mimic real world situations.
27. What is meant by loop testing?
Loop testing is a white box testing techniques that
focuses

exclusively

on

the

validity

of

loop

constructs. This technique can be applied to simple
loops,

nested

loops,

concatenated

loops

and

unstructured loops.
28. What is meant by smoke testing?
Smoke testing is an integration testing approach
that is commonly used ehen “shrink wrapped ”
software products are being developed.
29. What is alpha and beta tests?
Alpha test is the test that is conducted at the
developer’s site by a customer. Beta test is the
test that is conducted at one or more customer
sites by the end-user of the software.
30. What is meant by system testing?
System testing is actually a series of different tests
whose primary purpose is to fully exercise the
computer based system. It verifies whether the

system elements have been properly integrated
and perform the allocated functions.
31. Mention
the
categories
of
approaches?
There are three

categories

debugging

of

debugging

approaches as follows :
Brute force
Back tracking
Cause elimination
32. Define metric?
IEEE93 defines as a quantitative measure of the
degree to which a system, componen, or process
possesses a given attribute.
33. Mention some of the
appropriate

for

the

process
software

models
to

be

engineered?
Linear sequential or waterfall model
Prototyping model
Rad model
Incremental model
Spiral model
Winwin spiral model
Component based development model
34. What is adaptive maintenance?
Adaptive maintanence is the maintenance to adapt
software to a different operating environment. It
involves changing a system so that it operates in a
different

environment

from

its

initial

implementation.
35. What are the advantages and disadvantages
of black box testing?
Advantages:
Simulates
makes

no

actual
system

system
structure

usage.
assumptions.

Disadvantages :
Potential of missing logical errors in software.
Possibility of redundant testing.
36. What are the broad categories of system
requirements?
System requirements may be either functional or
non-functional requirements.
37. What are user requirements?
User requirements should describe functional and
non-functional requirements so that they are
understandable by system users who don’t have
detailed technical knowledge. User requirements
are defined using natural language, tables and
diagrams.
38. What is test scenario ?
Test scenario is the hypothetical story to test the
particular functionality of an application. It serves
as an input to functional testing. For test scenario
we need use case.
39. Define an analysis model?
An analysis model is a set of models that serves as
the technical representation of system.
40. Define prototype?
Prototype is an initial version of a software system
which is used to demonstrate concepts, try out
design options and generally to find out more

about the problem and its possible solutions.
41. What is the function of the user model?
The user model establishes the profile of end users
of the system.
42. What is system image?
The system image combines

the

outward

manifestation of the computer based system,
coupled

with

all

supporting

information

that

describes system syntax and semantics.
43. what is transform mapping?
Transform mapping is a set of design steps that
allows a DFD with transform flow charactersistics
to be mapped into a specific architectural style.
44. What is tracebility matrix?
Traceability matrix is a document in which we map
the test cases with the requirements. In general
we check whether the application works as per
requirements or whether we had covered all the
required functionality through test cases.
45. List the metrics for specifying non functional
requirements?
The possible metrics

that

specify

the

non-

functional requirements are :
Speed
Size
Easy of use
Reliability
46. What is the difference between black box
testing and white box testing?
Black box testing :
No knowledge of the internal logic of the

system is used to develop test cases.
Uses validation techniques.
Applied during later stages of testing.
Examples include unit testing, integration
testing, system testing, acceptance testing.
White box testing :
Knowledge of the internal logic of the system
is used to develop test cases.
Uses verification techniques
Performed early in the testing process.
47. Mention the various types of maintenance?
The various types of maintenance are :
Corrective maintenance
Adaptive maintenance
Perfective maintenance
Preventive maintenance
48. What is the difference between software
engineering and system engineering?
System Engineering - is concerned with all
aspects of computer based systems development
including

hardware,

software

and

process

engineering.
System Engineering - are involves in system
specification architectural design intergration and
deployment.

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