1. UNIT: II
I. COMPUTER SOFTWARE
The term software refers to set of computer programs, procedures and
associated programs, documents describing the programs and how
they are used.
A software package is a group of programs that solve a specific
problem or performs a specific type of job eg: a word processing
package may contain programs for text editing, formatting, drawings,
graphics,etc. hence,a multipurpose computer syatem has a several
software package one each foe each type of job it can perform.
APPLICATION & SYSTEM SOFTWARE
Software refers to a collection of programmes & associated documents.
There are two types of software:-
o System Software: It is a set of 1 or more programs, which controls
the operation &/or extends the processing capability of a computer
system. It makes the operation of a computer system more effective
& efficient. It helps hardware components work together & provide
support for the development & execution of application software
(programs).Good system software enables development & execution
of application packages on a computer system with less time &
efforts. A computer without some kind of system would be very
ineffective & most likely impossible to operate. Programs included
in a system software package are called system programs &
programmers who prepare system software are referred as system
programmer.
o Application Software: It is a set of 1 or more programs, which
solves a specific problem, or does a specific task. Programs
included in an application software package are called application
programs & programmers who prepare system software are
referred as application programmer.
1. PROGRAMMING LANGUAGES AND THEIR SOFTWARE
A programming language is an artificial language designed to
communicate instructions to a machine, particularly a computer.
Programming languages can be used to create programs that control
the behavior of a machine and/or to express algorithms precisely.
o Object-Oriented Programming Languages:
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2. Known as the newest and most powerful paradigms, object-oriented
programming requires the designer to specify the data structures as well
as the types of operations to be applied on those data structures. The
pairing of data, and the operations that can be done on it is called an
object. A program made using this language is therefore made up of a set
of cooperating objects instead of an instructions list. The most famous
object-oriented programming these days are C#, C , Visual Basic, Java,
and Python.
o Structured Programming Languages:
An exceptional type of procedural programming, structured programming
provides programmers with additional tools to handle the problems
created by larger programs. When using this language, programmers are
required to cut program structure into small pieces of code that can
easily be understood. Instead of using global variables, it employs
variables that are local to every subroutine. Among the popular features
of structured programming is that it doesn't accept GOTO statement
which is usually associated with the top-down approach. Such approach
starts with an opening overview of the system with minimal details about
the various parts. To add these details, design iterations are then
included to complete the design. Commonly used structured languages
include C, Pascal, and ADA.
o Procedural Programming Languages:
Procedural Programming involves a list of operations the program
needs to complete to be able to attain the preferred state. It is a
simple programming paradigm where every program comes with a
starting phase, a list of tasks and operations, and an ending stage.
Also called imperative programming, this approach comes with
small sections of code that perform certain functions. These
sections are made up of procedures, subroutines, or methods. A
procedure is made up of a list of computations that should be
done. Procedural programming lets a part of the code to be used
again without the need to make several copies. It achieves this by
dividing programmatic tasks into small sections. Because of this,
programmers are also capable of maintaining and understanding
program structure. Among the known procedural languages are
BASIC and FORTRAN.
2. ASSEMBLERS, COMPILERS & INTERPRETERS
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3. o Assemblers: For an assembly language, a computer program
to translate between lower-level representations of computer
programs. An assembler converts basic computer
instructions into a pattern of bits which can be easily
understood by the computer and the processor can use it to
perform its basic operations.
o Compilers: A compiler is a computer program (or set of
programs) that transforms source written in a programming
language (the source language) into another computer
language (the target language, often having a binary form
known as object code). The most common reason for wanting
to transform source code is to create an executable program.
The name "compiler" is primarily used for programs that
translate source code from a high-level programming
language to a lower level language (e.g., assembly
language or machine code). If the compiled program can run
on a computer whose CPU or operating system is different
from the one on which the compiler runs, the compiler is
known as a cross-compiler. A program that translates from a
low level language to a higher level one is adecompiler. A
program that translates between high-level languages is
usually called a language translator, source to source
translator, orlanguage converter. A language rewriter is
usually a program that translates the form of expressions
without a change of language.
o Interpreters: An interpreter normally means a computer
program that executes, i.e. performs, instructions written in
a programming language. An interpreter may be a program
that either
 Executes the source code directly
 translates source code into some
efficient intermediate representation (code) and
immediately executes this
 explicitly executes stored precompiled code made by
a compiler which is part of the interpreter system
OPERATING SYSTEMS
Meaning
Operating system is a integrated set of programs that control the
resources (cpu,i/o devices etc. ) of a computer system and provides its
users with an interface or virtual machine that is easier to use than the
bare machine. it has two main objectives :-
1) make a computer system easier to use
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4. 2) manage the resources of computer system.
7. TYPES OF OPERATING SYSTEMS
• Batch Processing Operating System:In a batch processing operating
system interaction between the user and processor is limited or
there is no interaction at all during the execution of work. Data
and programs that need to be processed are bundled and collected
as a ‘batch’ and executed together.
• Multi-Tasking Operating System:In this type of OS several
applications maybe simultaneously loaded and used in the
memory. While the processor handles only one application at a
particular time it is capable of switching between the applications
effectively to apparently simultaneously execute each application.
This type of operating system is seen everywhere today and is the
most common type of OS, the Windows operating system would be
an example.
• Real-time Operating System:A real-time operating system processes
inputs simultaneously, fast enough to affect the next input or
process. Real-time systems are usually used to control complex
systems that require a lot of processing like machinery and
industrial systems.
• Single User Operating System:A single user OS as the name
suggests is designed for one user to effectively use a computer at a
time.
• Multi-User Operating System:This type of OS allows multiple users
to simultaneously use the system, while here as well, the processor
splits its resources and handles one user at a time, the speed and
efficiency at which it does this makes it apparent that users are
simultaneously using the system, some network systems utilize
this kind of operating system.
• Distributed Operating System:In a distributed system, software and
data maybe distributed around the system, programs and files
maybe stored on different storage devices which are located in
different geographical locations and maybe accessed from different
computer terminals.
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5. DBMS
COMPONENTS OF DATABASE SYSTEM
A database system is composed of four components;
• Data
• Hardware
• Software
• Users
1. Data - It is a very important component of the database system. Most
of the organizations generate, store and process 1arge amount of data.
The data acts a bridge between the machine parts i.e. hardware and
software and the users which directly access it or access it through some
application programs.
2. Hardware - The hardware consists of the secondary storage devices
such as magnetic disks (hard disk, zip disk, floppy disks), optical disks
(CD-ROM), magnetic tapes etc. on which data is stored together with the
Input/Output devices (mouse, keyboard, printers), processors, main
memory etc. which are used for storing and retrieving the data in a fast
and efficient manner. Since database can range from those of a single
user with a desktop computer to those on mainframe computers with
thousand of users, therefore proper care should be taken for choosing
appropriate hardware devices for a required database.
3. Software - The Software part consists of DBMS which acts as a bridge
between the user and the database or in other words, software that
interacts with the users, application programs, and database and files
system of a particular storage media (hard disk, magnetic tapes etc.) to
insert, update, delete and retrieve data. For performing these operations
such as insertion, deletion and updation we can either use the Query
Languages like SQL, QUEL, Gupta SQL or application softwares such as
Visual 3asic, Developer etc.
4. Users - Users are those persons who need the information from the
database to carry out their primary business responsibilities i.e.
Personnel, Staff, Clerical, Managers, Executives etc. On the basis of the
job and requirements made by them they are provided access to the
database totally or partially.
Database management system concepts
1) Data Definition Language (DDL) statements are used to define the
database structure or schema. A popular data manipulation language is
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6. that of Structured Query Language (SQL), which is used to retrieve and
manipulate data in arelational database.Some examples:
o CREATE - to create objects in the database
o ALTER - alters the structure of the database
o DROP - delete objects from the database
o TRUNCATE - remove all records from a table, including all spaces
allocated for the records are removed
o COMMENT - add comments to the data dictionary
o RENAME - rename an object
Syntax : The create table statement does exactly that:
CREATE TABLE <table name> (
<attribute name 1> <data type 1>,
...
<attribute name n> <data type n>);
The data types that you will use most frequently are character
strings, which might be called VARCHAR or CHAR for variable or
fixed length strings; numeric types such as NUMBER or
INTEGER, which will usually specify a precision; and DATE or
related types. Data type syntax is variable from system to
system; the only way to be sure is to consult the documentation
for your own software.
2) Data Manipulation Language (DML) statements are used for managing
data within schema objects. The Data Manipulation Language (DML) is a
subset of SQL programming language used to retrieve, insert and modify
database information. These commands will be used by all database
users during the routine operation of the database Some examples:
o SELECT - retrieve data from the a database
o INSERT - insert data into a table
o UPDATE - updates existing data within a table
o DELETE - deletes all records from a table, the space for the records
remain
o MERGE - UPSERT operation (insert or update)
o CALL - call a PL/SQL or Java subprogram
o EXPLAIN PLAN - explain access path to data
o LOCK TABLE - control concurrency
Syntax :
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7. 1)The insert statement is used, obviously, to add new rows to a table.
INSERT INTO <table name>
VALUES (<value 1>, ... <value n>);
The comma-delimited list of values must match the table
structure exactly in the number of attributes and the data type
of each attribute. Character type values are always enclosed in
single quotes; number values are never in quotes; date values
are often (but not always) in the format 'yyyy-mm-dd' (for
example, '2006-11-30').
Yes, you will need a separate INSERT statement for every row.
2) The update statement is used to change values that are already in
a table.
UPDATE <table name>
SET <attribute> = <expression>
WHERE <condition>;
The update expression can be a constant, any computed value,
or even the result of a SELECT statement that returns a single
row and a single column. If the WHERE clause is omitted, then
the specified attribute is set to the same value in every row of the
table (which is usually not what you want to do). You can also
set multiple attribute values at the same time with a comma-
delimited list of attribute=expression pairs.
3) The delete statement does just that, for rows in a table.
DELETE FROM <table name>
WHERE <condition>;
If the WHERE clause is omitted, then every row of the table is
deleted (which again is usually not what you want to do)—and
again, you will not get a “do you really want to do this?”
message.
3) Data Control Language (DCL) statements DCL is abbreviation of Data
Control Language. It is used to create roles, permissions, and referential
integrity as well it is used to control access to database by securing it..
Some examples:
o GRANT - gives user's access privileges to database
o REVOKE - withdraw access privileges given with the GRANT
command
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8. 9. TRADITIONAL FILE CONCEPTS AND
ENVIORNMENT
The traditional file-oriented approach to information processing has for
each application a separate master file and its own set of personal files.
COBOL language supported these file-oriented applications. It was used
for developing applications such as of payroll, inventory, and financial
accounting. However, in general an organization needs flow of
information across these applications also and this requires sharing of
data, which is very difficult to implement in the traditional file approach.
In addition, a major limitation of file-based approach is that the
programs are dependent on the files and the files are dependent upon
the programs.These file-based approaches, which came into being as the
first commercial applications of computers, suffered from the following
significant disadvantages:
1. Data Redundancy: In a file system if an information is needed by
two distinct applications, then it may be stored in two or more
files. For example, the particulars of an employee may be stored in
payroll and leave record applications separately. Some of this
information may be changing, such as the address, the pay drawn,
etc. It is therefore quite possible that while the address in the
master file for one application has been updated the address in the
master file for second application may have not been. Sometimes,
it may not be easy to find that in how many files the repeating
items such as the address has occurred. The solution, therefore, is
to avoid this data redundancy by storing the address at just one
place physically, and making it accessible to all applications.
2. Program/Data Dependency: In the traditional file oriented
approach if a data field (attribute) is to be added to a master file,
all such programs that access the master file would have to be
changed to allow for this new field that would have been added to
the master record. This is referred to as data dependence.
3. Lack of Flexibility: Since the data and programs are strong
coupled in a traditional system, most information retrieval
requests would be limited to well anticipated and pre-determined.
The system would normally be capable of producing scheduled
records and queries that it has been programmed to create. In the
fast moving and competent business environment of today, apart
from such regularly scheduled records, there is a need for
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9. responding to un-anticipatory queries and some kind of
investigative analysis that could not have been envisaged
professionally.
11. ER MODELLING
An entity-relationship model (ERM) is an abstract and conceptual
representation of data. Entity-relationship modeling is a database
modeling method, used to produce a type of conceptual
schema or semantic data model of a system, often a relational database,
and its requirements in atop-down fashion. Diagrams created by this
process are called entity-relationship diagrams, ER diagrams,
or ERDs. An entity may be defined as a thing which is recognized as
being capable of an independent existence and which can be uniquely
identified. An entity is an abstraction from the complexities of some
domain. When we speak of an entity we normally speak of some aspect of
the real world which can be distinguished from other aspects of the real
world. An entity may be a physical object such as a house or a car, an
event such as a house sale or a car service, or a concept such as a
customer transaction or order. Although the term entity is the one most
commonly used, following Chen we should really distinguish between an
entity and an entity-type. An entity-type is a category. An entity, strictly
speaking, is an instance of a given entity-type. Examples: a computer, an
employee, a song, a mathematical theorem.A relationship captures how
two or more entities are related to one another. Relationships can be
thought of as verbs, linking two or more nouns. Examples:
an owns relationship between a company and a computer,
a supervises relationship between an employee and a department,
a performs relationship between an artist and a song,
a proved relationship between a mathematician and a theorem.
: Two related entities
Entities and relationships can both have attributes. Examples:
an employee entity might have a Social Security Number (SSN) attribute;
the proved relationship may have a date attribute.Every entity (unless it
is a weak entity) must have a minimal set of uniquely identifying
attributes, which is called the entity's primary key.Entity-relationship
diagrams don't show single entities or single instances of relations.
Rather, they show entity sets and relationship sets. Example: a
particular song is an entity. The collection of all songs in a database is
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10. an entity set. The eaten relationship between a child and her lunch is a
single relationship. The set of all such child-lunch relationships in a
database is a relationship set. In other words, a relationship set
corresponds to a relation in mathematics, while a relationship
corresponds to a member of the relation.
: An entity with an attribute
: A relationship with an attribute
: Primary key
12. INTEGRITY CONSTRAINTS
Integrity constraints are used to ensure accuracy and consistency of data
in a relational database. Data integrity is handled in a relational
database through the concept of referential integrity. There are many
types of integrity constraints that play a role in referential integrity.
Codd initially defined two sets of constraints but, in his second version of
the relational model, he came up with five integrity constraints:
• Entity integrity
The entity integrity constraint states that no primary key value can be
null. This is because the primary key value is used to identify individual
tuples in a relation . Having null value for the primary key implies that
we cannot identify some tuples.This also specifies that there may not be
any duplicate entries in primary key column key row.
• Referential Integrity
The referential integrity constraint is specified between two relations and
is used to maintain the consistency among tuple's in the two relations.
Informally, the referential integrity constraint states that a tuple in one
relation that refers to another relation must refer to an existing tuple in
that relation.It is a rule that maintains consistency among the rows of
the two relations
• Domain Integrity
The domain integrity states that every element from a relation should
respect the type and restrictions of its corresponding attribute. A type
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11. can have a variable length which needs to be respected. Restrictions
could be the range of values that the element can have, the default value
if none is provided, and if the element can be NULL.
• User Defined Integrity
e.g.: Age>=18 && Age<=60
Different keys in DBMS
1)Alternate key: An alternate key is any candidate key which is not
selected to be the primary key . This is done to prevent incorrect data
from entering a table (a duplicate entry is not valid in a unique column)
and to make the database more complete and useful. These could be
called alternate keys.
2) Candidate key - A candidate key is a field or combination of fields that
can act as a primary key field for that table to uniquely identify each
record in that table. Eg:The table: Emloyee (Name, Address, Ssn,
Employee_Id, Phone_ext ) In the above example Ssn no. and employee
identity are candidate keys.
3) Compound key :compound key (also called a composite key or
concatenated key) is a key that consists of 2 or more attributes.
4) Primary key - a primary key is a value that can be used to identify a
unique row in a table. Attributes are associated with it. Examples of
primary keys are Social Security numbers (associated to a specific
person) or ISBNs (associated to a specific book). In the relational model
of data, a primary key is a candidate key chosen as the main method of
uniquely identifying a tuple in a relation. For Eg: Emloyee
(Name,Address,Ssn,Employee_Idprimary_key,Phone_ext)
5) Foreign key - a foreign key (FK) is a field or group of fields in a
database record that points to a key field or group of fields forming a key
of another database record in some (usually different) table. Usually a
foreign key in one table refers to the primary key (PK) of another table.
6) Surrogate keys : A surrogate key can be used as the primary key. In
other situations there may be more than one candidate key for a relation,
and no candidate key is obviously preferred. A surrogate key may be
used as the primary key to avoid giving one candidate key artificial
primacy over the others.
Since primary keys exist primarily as a convenience to the programmer,
surrogate primary keys are often used—in many cases exclusively—in
database application design.
7) Unique key : a unique key can uniquely identify each row in a table,
and is closely related to the Superkey concept. A unique key comprises a
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12. single column or a set of columns. No two distinct rows in a table can
have the same value (or combination of values) in those columns if NULL
values are not used. Depending on its design, a table may have
arbitrarily many unique keys but at most one primary key.
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13. UNIT III
DATA COMMUNICATION & NETWORK
1. CONCEPT OF DATA COMMUNICATION
These basic concepts of data communications are:
1.1. Send and Receive Data
Send/write data: A program sends a value for a data point, and
the Data Hub records, or writes, the value for that point. This type
of communication is synchronous. The send and the write are
essentially two parts of a single process, so we use the terms pretty
much interchangeably. You can write a value to the Data Hub
manually using the Data Browser.
A typical write command from a program using DDE protocol
is DDEPoke.
Receive/read data: A program requests to receive the value of a
data point. The Data Hub then responds by sending the current
value of the point. We call this reading the value from the Cascade
Data Hub. Again, we sometimes use the two terms
interchangeably, and again, this type of communication
is synchronous.
A typical read command from a program using DDE protocol
is DDERequest.
'Automatic' Receive: It is possible to set up live data channels,
where a program receives updates on data points sent from the
Cascade Data Hub. How it works is the program sends an initial
request to the Data Hub to register for all changes to a data point.
The Data Hub immediately sends the current value of the point,
and then again whenever it changes. The Data Hub can receive
data automatically in a similar way. This asynchronous type of
communication is sometimes referred to as publish-subscribe.
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14. A DDEAdvise command sets up this type of connection, which is
called an advice loop.
1.1.2. Client - Server
Exchanging data with the Cascade DataHub is done through a client-
server mechanism, where the client requests a service, and
the server provides the service. Depending on the programs it interacts
with, the DataHub is capable of acting as a client, as a server, or as both
simultaneously.
The client-server relationship itself does not determine the direction of
data flow. For example, a client may read data from the server, or it
might write data to the server. The data can flow either way; the client
might initiate a read or a write, and the server would respond.
1.1.3. Synchronous and Asynchronous Communication
Every type of communication, natural or man made comes in two basic
forms: synchronous or asynchronous.
Synchronous communication means that for each message, the
sender expects to get a reply from the receiver, like a telephone
call. There is a back-and-forth exchange, so that each party knows
that the other is receiving the message. If there is no response, you
can be pretty sure that communication didn't occur.
Asynchronous communication means that a message gets sent but
the receiver is not expected to reply, like a radio broadcast or a
newspaper.
Each of these communication types has its own value and purpose in
data communications, and the Cascade Data Hub is capable of both. The
specific circumstances and application will determine which form of
communication you end up using.
COMMUNICATION MEDIA
Computer networks can be classified according to the hardware and
associated software technology that is used to interconnect the individual
devices in the network, such as electrical cable (Home PNA, power line
communication, Ghn), optical fiber, and radio waves(wireless LAN).
A well-known family of communication media is collectively known
as Ethernet. It is defined by IEEE 802 and utilizes various standards and
media that enable communication between devices. Wireless LAN
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15. technology is designed to connect devices without wiring. These devices
use radio waves or infrared signals as a transmission medium.
Wired technologies
1) Twisted pair wire is the most widely used medium for
telecommunication. Twisted-pair cabling consist of copper
wires that are twisted into pairs. Ordinary telephone wires
consist of two insulated copper wires twisted into pairs.
Computer networking cabling (wired Ethernet as defined
by IEEE 802.3) consists of 4 pairs of copper cabling that can
be utilized for both voice and data transmission. The use of
two wires twisted together helps to
reduce crosstalk and electromagnetic induction. The
transmission speed ranges from 2 million bits per second to
10 billion bits per second. Twisted pair cabling comes in two
forms which are Unshielded Twisted Pair (UTP) and Shielded
twisted-pair (STP) which are rated in categories which are
manufactured in different increments for various scenario.
2) Coaxial cable is widely used for cable television systems,
office buildings, and other work-sites for local area networks.
The cables consist of copper or aluminum wire wrapped with
insulating layer typically of a flexible material with a high
dielectric constant, all of which are surrounded by a
conductive layer. The layers of insulation help minimize
interference and distortion. Transmission speed range from
200 million to more than 500 million bits per second.
3) ITU-T G.hn technology uses existing home wiring (coaxial
cable, phone lines and power lines) to create a high-speed
(up to 1 Gigabit/s) local area network.
4) Optical fiber cable consists of one or more filaments of
glass fiber wrapped in protective layers that carries data by
means of pulses of light. It transmits light which can travel
over extended distances. Fiber-optic cables are not affected
by electromagnetic radiation. Transmission speed may reach
trillions of bits per second. The transmission speed of fiber
optics is hundreds of times faster than for coaxial cables and
thousands of times faster than a twisted-pair wire.
Wireless technologies
1) Terrestrial microwave – Terrestrial microwaves use Earth-based
transmitter and receiver. The equipment looks similar to satellite
dishes. Terrestrial microwaves use low-gigahertz range, which
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16. limits all communications to line-of-sight. Path between relay
stations spaced approx, 48 km (30 mi) apart.
2) Communications satellites – The satellites use microwave radio as
their telecommunications medium which are not deflected by the
Earth's atmosphere. The satellites are stationed in space, typically
35,400 km (22,000 mi) (for geosynchronous satellites) above the
equator. These Earth-orbiting systems are capable of receiving and
relaying voice, data, and TV signals.
3) Cellular and PCS systems – Use several radio communications
technologies. The systems are divided to different geographic areas.
Each area has a low-power transmitter or radio relay antenna
device to relay calls from one area to the next area.
4) Wireless LANs – Wireless local area network use a high-frequency
radio technology similar to digital cellular and a low-frequency
radio technology. Wireless LANs use spread spectrum technology
to enable communication between multiple devices in a limited
area.
5) Infrared communication can transmit signals between devices
within small distances of typically no more than 10 meters. In
most cases,line-of-sight propagation is used, which limits the
physical positioning of communicating devices.
6) A global area network (GAN) is a network used for supporting
mobile across an arbitrary number of wireless LANs, satellite
coverage areas, etc. The key challenge in mobile communications
is handing off the user communications from one local coverage
area to the next. In IEEE Project 802, this involves a succession of
terrestrial wireless LANs
CONCEPT OF COMPUTER NETWORKS
A computer network, often simply referred to as a network, is a collection
of hardware components and computers interconnected by
communication channels that allow sharing of resources and
information.
Networks may be classified according to a wide variety of characteristics
such as the medium used to transport the data, communications
protocol used, scale, topology, and organizational scope.
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17. INTRANET & EXTRANETS
13(B) EXTRANETS
An extranet is a computer network that allows controlled access from
the outside, for specific business or educational purposes. An extranet
can be viewed as an extension of a company's intranet that is extended
to users outside the company, usually partners, vendors, and suppliers.
It has also been described as a "state of mind" in which the Internet is
perceived as a way to do business with a selected set of other companies
(business-to-business, B2B), in isolation from all other Internet users. In
contrast, business-to-consumer (B2C) models involve known servers of
one or more companies, communicating with previously unknown
consumer users. An extranet is like a DMZ in that it provides access to
needed services for channel partners, without granting access to an
organization's entire network.
UNIT –IV: FUNCTIONAL AND ENTERPRISE
SYSTEMS
1. DATA, INFORMATION & KNOWLEDGE CONCEPTS
The term data refers to qualitative or quantitative attributes of
a variable or set of variables. Data (plural of "datum") are typically the
results of measurements and can be the basis of graphs, images, or
observations of a set of variables. Data are often viewed as the lowest
level of abstraction from which information and then knowledge are
derived. Raw data, i.e. unprocessed data, refers to a collection
of numbers, characters, images or other outputs from devices that collect
information to convert physical quantities into symbols.
Information in its most restricted technical sense is a message
(utterance or expression) or collection of messages that consists of
an ordered sequence of symbols, or it is the meaning that can be
interpreted from such a message or collection of messages. Information
can be recorded or transmitted. It can be recorded as signs, or conveyed
as signals by waves. Information is any kind of event that affects
the state of a dynamic system. The concept has numerous other
meanings in different contexts.
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18. Knowledge is a familiarity with someone or something, which can
include information, facts, descriptions, and/or skills acquired
through experience or education. It can refer to the theoretical or
practical understanding of a subject. It can be implicit (as with practical
skill or expertise) or explicit (as with the theoretical understanding of a
subject); and it can be more or less formal or systematic.[1] In philosophy,
the study of knowledge is called epistemology, and the
philosopher Plato famously defined knowledge as "justified true belief."
There is however no single agreed upon definition of knowledge, and
there are numerous theories to explain it. Knowledge acquisition involves
complex cognitive processes: perception, learning, communication,
association and reasoning; while knowledge is also said to be related to
the capacity of acknowledgment in human beings.
2. DECISION MAKING PROCESS
The figure given below suggests the steps in the decision-making
process:-
• Identifying the Problem: Identification of the real problem before
a business enterprise is the first step in the process of decision-
making. It is rightly said that a problem well-defined is a problem
half-solved. Information relevant to the problem should be
gathered so that critical analysis of the problem is possible. This is
how the problem can be diagnosed. Clear distinction should be
made between the problem and the symptoms which may cloud
the real issue. In brief, the manager should search the 'critical
factor' at work. It is the point at which the choice applies.
Similarly, while diagnosing the real problem the manager should
consider causes and find out whether they are controllable or
uncontrollable.
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19. • Analyzing the Problem: After defining the problem, the next step
in the decision-making process is to analyze the problem in depth.
This is necessary to classify the problem in order to know who
must take the decision and who must be informed about the
decision taken.
• Uniqueness of the decision.: Collecting Relevant Data: After
defining the problem and analyzing its nature, the next step is to
obtain the relevant information/ data about it. There is
information flood in the business world due to new developments
in the field of information technology. All available information
should be utilized fully for analysis of the problem. This brings
clarity to all aspects of the problem.
• Developing Alternative Solutions: After the problem has been
defined, diagnosed on the basis of relevant information, the
manager has to determine available alternative courses of action
that could be used to solve the problem at hand. Only realistic
alternatives should be considered. It is equally important to take
into account time and cost constraints and psychological barriers
that will restrict that number of alternatives. If necessary, group
participation techniques may be used while developing alternative
solutions as depending on one solution is undesirable.
• Selecting the Best Solution: After preparing alternative
solutions, the next step in the decision-making process is to select
an alternative that seems to be most rational for solving the
problem. The alternative thus selected must be communicated to
those who are likely to be affected by it. Acceptance of the decision
by group members is always desirable and useful for its effective
implementation.
• Converting Decision into Action: After the selection of the best
decision, the next step is to convert the selected decision into an
effective action. Without such action, the decision will remain
merely a declaration of good intentions. Here, the manager has to
convert 'his decision into 'their decision' through his leadership.
For this, the subordinates should be taken in confidence and they
should be convinced about the correctness of the decision.
Thereafter, the manager has to take follow-up steps for the
execution of decision taken.
• Ensuring Feedback: Feedback is the last step in the decision-
making process. Here, the manager has to make built-in
arrangements to ensure feedback for continuously testing actual
developments against the expectations. It is like checking the
effectiveness of follow-up measures. Feedback is possible in the
form of organised information, reports and personal observations.
Feed back is necessary to decide whether the decision already
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20. taken should be continued or be modified in the light of changed
conditions.
3. PHYSICAL COMPONENTS OF INFORMATION SYSTEM
An information system is a system that accepts data resources as input
and processes them into information products as output. This information
system model highlights the relationships among the components and
activities of information systems.
Information System Resources:
(i) People Resources:
People are required for the operation of all information systems. These
people resources include:
• End users (also called users or clients) are people who use an
information system or the information it produces. They can be
accountants, salespersons, engineers, clerks, customers, or managers.
Most of us are information system end users.
• IS Specialists are people who develop and operate information systems.
They include systems analysts, programmers, computer operators, and
other managerial technical, and clerical IS personnel. Briefly, systems
analysts design information systems based on the information
requirements of end uses, programmers prepare computer programs
based on the specifications of systems analysts, and computer
operators operate large computer systems.
(ii) Hardware Resources:
The concept of Hardware resources includes all physical devices and
materials used in information processing. Specially, it includes not
only machines, such as computers and other equipment, but also all
data media, that is, all tangible objects on which data is recorded, from
sheets of paper to magnetic disks.
(iii) Software Resources:
The concept of Software Resources includes all sets of information
processing instructions. This generic concept of software includes not
only the sets of operating instructions called programs, which direct and
control computer hardware, but also the sets of information processing
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21. instructions needed by people, called procedures.It is important to
understand that even information systems that don’t use computers
have a software resource component. This is true even for the
information systems of ancient times, or the manual and machine-
supported information systems still used in the world today. They all
require software resources in the form of information processing
instructions and procedures in order to properly capture, process, and
disseminate information to their users.
iv) Data Resources:
Data is more than the raw material of information systems. The concept
of data resources has been broadened by managers and information
systems professionals. They realize that data constitutes a valuable
organization resource. Thus, you should view data as data resources that
must be managed effectively to benefit all end users in an organization.
Data can take many forms, including traditional alphanumeric data,
composed of numbers and alphabetical and other characters that
describe business transactions and other events and entities. Text data,
consisting of sentences and paragraphs used in written communications;
image data, such as graphic shapes and figures; and audio data, the
human voice and other sounds, are also important forms of data.
The data resources of information systems are typically organized into:
• Database that hold processed and organized data.
• Knowledge bases that hold knowledge in variety of forms such as facts,
rules, and case examples about successful business practices.
For example, data about sales transactions may be accumulated and
stored in a sales database for subsequent processing that yields daily,
weekly, and monthly sales analysis reports for management. Knowledge
bases are used by knowledge management systems and expert systems
to share knowledge and give expert advice on specific subjects.
4. CLASSIFICATION OF INFORMATION SYSTEM
• Transaction Processing System (TPS): Applications of information
systems that process business transaction data. Its use at
operational level and focuses on the data. An example is a
computer application for typing.
• Management Information System (MIS):Applications of information
system that aims to provide information used in the field of
management (management-oriented reporting.) Examples are
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22. computer applications for hospital services, pharmacy purchasing,
scheduling of production machinery and others.
• Decision Support System (DSS):Applications of information
systems that provide decision-oriented information and especially
in situations where decision-making. At the executive level often
called Executive Information System. For example a computer
application to determine the purchase of drug stocks at the
hospital, the determination of sugar distribution system and
others.
• Expert System (ES):Information system designed to produce a
decision by reproducing knowledge and expertise of the decision
maker and problem solver and then simulate it. For example
advanced applications of artificial neural networks, face
recognition and so forth.
• Office automation system: Systems that support business
activities on a large scale. Examples ERP applications for the
company.
5. OVERVIEW OF SECURITY ISSUES IN INFORMATION
TECHNOLOGY
Information security means protecting information and information
systems from unauthorized access, use, disclosure, disruption,
modification, perusal, inspection, recording or destruction. The terms
information security, computer security and information assurance are
frequently incorrectly used interchangeably. These fields are interrelated
often and share the common goals of protecting
the confidentiality, integrity and availability of information; however,
there are some subtle differences between them.These differences lie
primarily in the approach to the subject, the methodologies used, and
the areas of concentration. Information security is concerned with the
confidentiality, integrity and availability of data regardless of the form the
data may take: electronic, print, or other forms.Computer security can
focus on ensuring the availability and correct operation of acomputer
system without concern for the information stored or processed by the
computer.Governments, military, corporations, financial
institutions, hospitals, and privatebusinesses amass a great deal of
confidential information about their employees, customers, products,
research, and financial status. Most of this information is now collected,
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23. processed and stored on electronic computers and transmitted
acrossnetworks to other computers.Should confidential information
about a business' customers or finances or new product line fall into the
hands of a competitor, such a breach of security could lead to lost
business, law suits or even bankruptcy of the business. Protecting
confidential information is a business requirement, and in many cases
also an ethical and legal requirement.For the individual, information
security has a significant effect on privacy, which is viewed very
differently in different cultures.The field of information security has
grown and evolved significantly in recent years. There are many ways of
gaining entry into the field as a career. It offers many areas for
specialization including: securing network(s) and allied infrastructure,
securing applications and databases,security testing, information
systems auditing, business continuity planning and digital
forensics science, etc.
6. EMERGING TRENDS OF INFORMATION TECHNOLOGY
Ten trends are identified consisting of aspects of: the difficulty of hiring
qualified labor in-country; establishment of strategy resides entirely
within the IT management; security remains a serious concern; offshore
subcontractors sometimes place their employees within Icelandic
companies; mid- and upper-level employees who can strategically
develop networks and systems are in strong demand; use of information
system (IS)/IT standards for information security is mostly voluntary;
generally, the establishment of IS/IT strategy does not remain with board
of directors; virtually all Icelandic corporations engage in, or have
engaged in, outsourcing over the past five years (11 sub-trends are
identified); and the business school curricula is inadequate to the needs
of Icelandic corporations with respect to IT demands.
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