ELECTRONIC COMMERCE

ELECTRONIC COMMERCE  

INTRODUCTION

The growth of Internet into a global market place attracts more business firms to use this
media for commerce. Business firms may use the Internet initially for communication. Websites
are set up to provide information about its products and services. Business firms offer corporate
information, product information, marketing related services etc,.
The Internet has integrated the fragment markets words over though in a modest way. But
this interaction is growing rapidly. The most important advantage of the internet for business
firms is that it allows reaching customers at very low costs.

 ELECTRONIC COMMERCE

Electronic commerce is the process of searching, choosing, buying and selling of
product or service on the electronic network; it uses the computer and communication networks
for promoting products, selling, delivery, collection and delivery service.

•  Electronic Commerce includes:

a) Buying and selling on the internet
b) Making payments electronically
c) Business transaction in which there is no physical exchange or physical contact.
d) It is transacting a business over am electronic network without physical contact.

• The problems connected with electronic commerce are:

a) Identity
b) Authentication
c) Protection of data
d) ConfidentialityThese problems can be solved by using:a) Secure socket layer and hypertext transfer protocol
b) Digital signatures
c) Using public key cryptography
d) Using digital certificates.

In E- commerce, the parties to a transaction interact electronically. They may be
separated by long distances physically, yet the electronic network bring them together not only to
complete a transaction but also to get after sales support, E-commerce is not just doing
transaction over the Internet, it aims at few other things as well like :

=> Web enabling an organization’s business so that it can facilitate better customer interaction,
handing customer enquiries receiving customer order and payments online.=>Improving customer service capabilities by allowing customers by providing Inert access to
its databases containing customer interest information.=> Use the web to gather customer need information and thus to reducing cycle time by
responding to customer needs quickly. It enables the firm in coming out with new available
new product information to customers.=> Raising productivity of all activities in the organization by improving the flow of information
in the organization.

 FEATURES OF E-COMMERCE:

E-Commerce has the following general features:
a) It is a business strategy to cut down costs, while improving quality and increasing the speed
of delivery of goods/services.
b) It has ability to sell and purchase products/services/information on computer networks.
c) It is a solution for office automation and quick business transactions.
d) It is a tool to improve intra business functioning like business re-engineering.
e) It is tools to improve inter business communication through easy and accurate interaction and
information interchange.

 IMPORTANCE OF E-COMMERCE

E-Commerce becomes inevitable because of the following:a) Low setup cost:Any body can easily set up a website. In fact there are many organizations and training
institutes who help customers in developing and launching websites. To market a product large
retail showrooms are not required, just a web site showing the characteristics of the product
including cost details are sufficient.

b) Global Free Market:Nobody can dominate the global market as presence on the internet is easy not only for
global giants, but even small organisations can participate actively at low costs and compete with
stiff competition.

c) Global Access:Since more than 200 countries are hooked onto the Internet, anybody who can afford a
TV and a telephone can fully access the Internet and gain the information required.

d) Availability of Technology:Since the same technology like web servers, browsers, engines, internet, etc., is used
throughout the world therefore business can be easily conducted.

e) Multiple Opportunities:By using E-Commerce multiple activities like selling, renting, purchasing etc. can be
performed. In fact a whole variety of transactions can be provided all under one roof.

f) Others:E-commerce systems are being established for automating and enhancing many aspects
of communications, publishing, marketing, sales and customer service such as:=> Customer Research;=>Pre-Sales Enquiries;=>Information Publishing and Dissemination;=> Sales;=> Advertising;=> Promotions;=>Public Relations;=> Purchasing;=> Transactions;=>Funds Transfer;=> Production; ` Delivery;=> After-Sales Service;=> Ongoing Relationship Management; and=> Customer Support.
The benefits of electronic commerce are not just available to large corporations and
government departments, and many small to medium businesses are discovering new cost -
effective opportunities to use Internet-related technology to help their business operations locally
and internationally.

 TYPES OF ELECTRONIC COMMERCEBased on the parties involved in electronic transactions, the e-commerce can be classified
into the following types.a) Business –to- Business (B2B)b) Business –to- Consumer (B2C)c) Consumer –to- Consumer (C2C)

a) Business –to-Business E-CommerceThis is done between business firms. For example, electronic transactions between a
manufacturing firm and its supplier firms are B2B transactions. This segment is the largest and
the fastest growing one in electronic, commerce. Here firm use the electronic network for
purchasing products, consulting services and paying for them.

b) Business –to- Consumer E-CommerceConsumers check electronic catalogues to learn about products and compare prices of
products sold. They purchase products at the firm’s website and may pay electronic cash or
other means like credit card.

c) Consumer –to- Consumer E-CommerceSome sites offer consumers to deal directly with each other. Auction sites are examples.
At these auction sites consumers can buy and sell products.

Electronic commerce is useful to both producers and consumers as it helps them
overcome the traditional barriers of distance from markets and lack of information about market
opportunities. Producers and traders no longer need to maintain physical establishments
requiring large capital outlays. Virtual shops and contact points on the Internet may enable
storage close to the production site and distribution can be made directly to the consumer.
Increased advertising possibilities world wide may help small and medium industries and
businesses that traditionally find it difficult to reach the consumer abroad. E- Commerce may
also enable such firms to eliminate middlemen while trying to sell their products abroad.

 E-COMMERCE ACTIVITIESBusiness firms use the internet platform for communication and commerce. The ecommerce activities can be discussed as follows:a) Direct marketing and sellingBusiness firms set up websites for direct marketing and selling. Direct selling was one of
the earliest forms of e-commerce. For example, Amazon.com, Barnes and noble and Dell
computers engaged in direct selling. Gradually firm moved on to one or more complex
operations on the web.

b) Value chain integrationE- Commerce does not tolerate any kind of delay. Delay in inventory tracking and
management can cripple the business. E- Commerce firm use EDI for exchanging transaction
data among them so that transactions are automatically processed. Thus suppliers, customers
and service providers will use open EDI for integrating their processing systems leading to mare
efficient operations.

c) Corporate purchasing:Internet provides opportunities for business firms to reduce cost of purchasing. Suppliers
keep their electronic catalogs updated. Comparative price information is also available.
Ordering can be electronically done to reduce the laborious paper work in purchasing.
Officers can approve purchase orders electronically. The firm can enforce policies; provide
greater services to customers and suppliers.

d) Financial and information servicesA wide range of financial services are offered on the internet. They include:=> Online banking=> Online billing=> Online securities transactions=>Secure information distribution

e) Mobile commerce:Mobile commerce is a part of e-commerce and differs from the latter on the use of mobile
telecommunication communication network in place of telecommunication network. Mcommerce includes only transactions with a monetary value and it excludes short message
services. One condition essential for the success of mobile commerce is large user base of
mobile phones. Adequate security for mobile transactions is another condition for its adoption in
a big way.

OPERATING SYSTEM

OPERATING SYSTEM  

INTRODUCTION

It is the first layer of software loaded into computer memory when it starts up. As the
first software layer, all other software that gets loaded after it depends on it for various common
core services. These common core services include disk access, memory management, takes
scheduling, and user interfacing. In addition the operating system ensures that different
programs executing at the same time do not interfere with each other. It provides a software
platform on top of which other programs can run. In simple words, the operating system
organizes and controls the hardware. Examples of operating systems are Windows XP, UNIX,
and Linux.

 OPERATING SYSTEM

The operating system is a software program that acts as an interface between the user and
the computer. It is used to control and manage the hardware components such as keyboard,
monitor, printer, scanner etc.

 FUNCTIONS OF AN OPERATING SYSTEM

a) Process Management:It handles the creation, deletion, suspension, resumption, and synchronization of process.

b) Memory Management:

It handles allocation and de-allocation of memory space as required by various programs.

c) File Management:It is responsible for creation and deletion of files and directories. It also organizes, stores,
retrieves, names, and protects all the files.

d) Device Management:It manages all the devices of the computer system such as printers and modems. If any
device fails, it detects the device failure and notifies the same to the user.

e) Security Management:Protects system resources and information against destruction and unauthorized use.

f) User interface:Provides the interface between the user and the hardware.


 TYPES OF OPERATING SYSTEMThese are the different types of operating system :

 DOS (Disk Operating System)

MS-DOS was the widely used operating system before the introduction of the Windows
operating system. Even now the MS-DOS commands are used for carrying out many jobs like
copying the files, deleting the files etc. The DOS is a set of computer programs. The mainfunctions of DOS are to manage files, allocate system resources according to the requirement. It
provides essential features to control hardware devices such a keyboard, screen, disk drives,
printers, modems etc. Thus, DOS is a medium through which the user and external devices
attached to the system communicate the command with the system. DOS translate
communication issued by the computer in the format that is understandable by the computer and
instruct computer to work accordingly. It is also translates the result and any error message in the
format for the user to understand.

• DOS Commands

We can type all DOS commands in either upper or lower case letters. There are two basic
types of DOS commands:

 Internal commands:

These commands, like COPY, DEL, and TYPE, are stored in computers memory. Many
DOS commands fall into this category.

 External commands:This group of commands is stored on the disk. To use them, either insert the DOS floppy
disk, or change to the directory on hard disk which contains DOS external commands. Examples
of external commands include FORMAT, DISKCOPY, and CHKDSK.

Some commands can take several forms. These separate forms are used by including
various parameters with the command. Parameters, which will be discussed with each command,
are indicate by a / mark. Here is an example of command with an attached parameter:
C:\>DIR/W
[DOS command DIR is attached with parameter W]
All DOS commands must be activated by pressing the <Enter> key after typing the
command.

• Features of DOS

=> Single user systemv=>Machine independence=>Program control=> Peripheral management=> Operating with Directories=> Managing files=> Processing commands=>Managing input and output=> Data securing=>Using Batch files=>Managing memory=> Setting up environment=>Command processing - DOS shell(a set of commands which is used to create the
programs)=>Operating with Assembler.

•  Advantages of DOS

The DOS provides the following advantages:=> Machine independence=>More security=>User friendly environment=> More useful in commercial applications.=> Error finding and recovery is more efficient=> Facilities more graphical user interfaces.=> Easy debugging

 WINDOWS OPERATING SYSTEM

Microsoft Windows is the most popular operating system around the world. Even those
who are new to computers can use it with a little practice. With the help of Windows, we can
operate the computer just by clicking the mouse buttons, Windows95, Windows98, Windows
2000 and Windows XP are the various versions of Windows.
Windows is an operating system. It is the extension of the disk operating system.
Windows is system software. It requires DOS to run the application programs. The DOS should
be loaded into the memory before the window is executed. After the windows is loaded into the
memory the windows environment takes all the device controls. It also takes care of the memory
management of the programs run by the windows software".

Types of windowsThere are two types of windows. They are

(a) Application windows - displays the executable program in graphical user interface mode.(b) Document window - generated by executable or application program.

1. Windows 98Windows 98 is the upgraded version of Windows 95. it offers bug fixture and minor
enhancements.

•  Features of Windows:

The important features of Windows 98 are as follows:(a) Graphical User InterfaceWindows 98 provides user-friendlier interface to work on. Its improved graphical user
interface makes learning and using windows 98 more natural and easier for all types of users. It
is more powerful, customizable and efficient.
(b) Type of icons (Small Pictures):

There are three types of icons. They arei) Applications icons - the minimized version of the currently running application programs. It
appears at the bottom of the desktop and can be maximized.ii) Document icons - the reduced document windows.iii) Program icons - appear with in program manager and clicking on these icons activate the
associated applications and also load the related documents or files.

(c) Start Button

Introduction of START button by windows 98 made life much simpler while there is a
need to access multiple programs. It is the gateway of accessing most of the functionality
available in the computer loaded with windows 98. Just Click on the start button anytime to start
any programs, open or find documents, change windows settings, get Help, manage Files,
maintain System, much more.

(d) TaskbarThe Task bar provides information and access to the entire task that has been currently
activated by windows 98. Using this one can keep a track of what all programs have been
activated and switched between them.

(e) Windows ExplorerWindows Explorer more or less acts as File Manager for windows 98, but with lots of
new features. It is more efficient, faster and user friendly. Using Explorer one can easily browse
through all the drives and network resources available and manage files.

(f) Right Mouse ButtonClicking on the right mouse button activates a pop-up menu in any program so as to help
in completing a task efficiently.

(g) Long File NamesAs the MS-DOS convention follows, none-of the file used in DOS environment should be
more than 8 character of primary name and optimal secondary name (extension) of three
characters. However Windows 98 has broken this barrier. Windows 98 supports long file names
maximum of 225 characters. It also allowed space to be used in between file name. This helps to
make files and folders (directory/subdirectory) easier to organize and find.

h) ShortcutsAs the name suggests, SHORTCUTS are the shortest way to access programs, files other
resources in Windows 98. Instead of going through the structural process of accessing a program,
one can create “shortcuts” to access them. It creates links for easy access to file, programs,
folders and more.

i) MultitaskingMultitasking allows the user to activate and accomplish more than one task at a time. For
example, work on a document file WORD programs, which copies file from other computer
available in time on the network. With Windows 98, 32 - bit computing environment, the user
can do more than one task a time.
j) Easy Internet AccessIntegration of Internet Explorer 4.0 and Active Desktop, which coupled the Internet html
hypertext links more tightly to the Windows 98 user interface.

k) Software CompatibilityWindows 98 provides complete backward compatibility. It is easily compatible with
other applications developed for MS-DOS and Windows 3.x environment. It also supports latest
32-bit technology. Most of the latest software packages are now built on Windows 98, operating
environment.

l) Great Gaming PlatformWindows 98 supports rich graphics, high quality audio and video. Software to take
advantage of Intel's Multimedia Extensions (MMX) to the IA - 32 instruction set, which are
designed to improve the performance of multimedia applications and games developed for
windows 98 that uses MMX technology.

m) Hardware CompatibilityWindows 98 provides greater Hardware compatibility as compared to any other operating
environment. It has flexibility of supporting hardware from different vendors.

n) Find utilityFind Utility of windows 98 allows the user to do searches by partial name, last modified
date, or full text. In addition we can save, rename or view files from within the result pane.

(o) HelpWindows 98 provides online help to accomplish a task. If the user is not sure how to
perform a task, windows 98 Help will provide structured process how to accomplish the task.
Simply right-click on any object in the user interface (icon) and he can get relevant description
about that object.

(p) Manage more numbers of PC'sWindows 98 can manage up to eight monitors on a- single PC. The user can drag and
drop resize and move desktop items such as windows, folders, icons, and applications, from one
monitor to the next.

(q) Additional facilities

Windows 98 includes additional enhancement of Windows 95 that includes new backup
utilities and disk defragmenter capabilities.

2. Windows NT workstationWindows NT is a single user; multitasking operating system designed to run on PC
workstations and incorporates all latest developments in operating system technology. It was
introduced in 1993. It includes the following:
(a) Windows NT workstation
(b) Windows NT server, and
(c) Windows NT enterprise edition

•  Features

a) Single User MultitaskingThe main feature is that even through it is meant for a single user environment, provides
multitasking. For e.g., a user may use a word processor, a drawing program, a spreadsheet
application to produce a document. Without multitasking, simultaneous use of this will not be
possible. They must process with the s/w one by one; provide alignment making changes will be
a tedious process. In a multitasking environment, the user may keep all the applications open,
prepare the documentation and make necessary change. All of these are possible with increased
speed and memory capacity of microprocessors together with the support for virtual memory.

b) Ability to support all applicationsThe power of Windows NT comes form its ability to support applications written for
other operating systems. This ability is provided through protected subsystems. The protected
subsystems are those parts of NT that interact with the end user.

c) Client server computing modelThe way in which the executive, the protected subsystems, and the applications structured
in NT is by using the client/ server computing model, each server implemented as one or more
process. Such process waits for a request from a client for of its services, eg. memory services. A
client, which may be an applications program or another operating system module, requests a
service by sending a message. The message routed through the executive to the appropriate
server. The server performs the operation and returns the results or status information by means
of another message, which is routed through the executive back to the client.
Client/server architecture has the following advantages:

(i) It simplifies the base operating system, the NT executive
(ii) It improves reliability. Each server runs on a separate process with its partition of
memory, protected from other servers. Also, the servers cannot directly access hardware
or modify memory in which the executive the rest, the operating system.
(iii) It provides a natural base for distributed computing.d) Support for ThreadsAn important feature of Windows NT is its support for threads within process. A thread is
a dispatchable unit of work. It is executed sequentially and may be interrupted so that the
processor can turn to other threads. A process is a collection of one or more areas and associated
system resources. This is similar to a program in execution. By checking an application into
multiple threads, the modularity and the timing of application related events could be
maintained.

e) Support of Symmetric Multiprocessing (SMP)In a multiprocessor system, to achieve maximum efficiency and reliability a mode of
operation known as symmetric multiprocessing (SMP) is desirable. With SMP, any process or
Thread can be assigned to any processor.
f) Windows NT uses concepts of object oriented designWindows NT uses some concepts of object oriented design. This approach facilitates the
sharing of resources and data among processes and the protection of resources and data among
processes and the protection of resources from unauthorized access.

• Advantages of Windows NT

a) It simplifies the base operating systemb) It improves reliabilityc) It provides a natural base of distributed computingd) Operating-system routines can run on any available processor and different routines can be
executed simultaneously on different processors.e) NT supports the use of multiple threads of execution within a single process.f) NT processes convenient mechanisms for sharing data and resources between processes.g) NT provides flexible inter process communication capabilities.g) Functionality-NT can communicate with many different types of computers.

 THE UNIX OPERATING SYSTEM

Like DOS and windows, there’s another operating system called UNIX. It arrived earlier
then the other two, and stayed back like enough to give us the internet. UNIX is a giant operating
system and is way ahead of them in sheer power. It has practically everything an operating
system should have, and several features which other operating systems never had. Its richness
and elegance go beyond the commands and tolls that constitute it, while simplicity permeates the
entire system. It runs on practically every hardware and provided motivation to the open source
movement.

However, UNIX also makes many demands of the user. In requires a different type of
commitment to understand the subject, even when the user is an experienced computer
professional. It introduces certain concepts not known to the computing community before, and
user numerous symbols whose meaning is anything but clear. It achieves unusual tasks with a
few keystrokes, but it takes time to devices a sequence of them for a specific task. Often, it
doesn’t tell you whether you are right or wrong, and doesn’t warn you of the consequences of
your actions. That is probably the reason why many people still prefer to stay away from UNIX.

•  Features of UNIX

UNIX is an operating system, so it is has all the features an operating system is expected
to have. However UNIX also looks at a few things differently and possesses features unique to it.
The following section gives a clear idea of the major features of this operating system.

a) UNIX: A Multi user SystemFrom the fundamental point of view, UNIX is a multiprogramming system; it permits
multiple programs to run. This can happen in two ways
Multiple users can run separate jobs
A single user can also run multiple jobs.

b) UNIX: A Multi tasking System TooA single user can also run multiple tasks at the same time as UNIX is a multitasking
system. It is usual for a user to edit a file, print another one on printer, send email to a friend and
browse the Word Wide Web - all without leaving any of the application. This kernel is designed
to handle a user’s multiple needs.

c) The UNIX ToolkitBy one definition, UNIX represents the kernel, but the kernel by itself doesn’t do much
that can benefit the user. To properly exploit the power of UNIX, you need to use the host of
applications that are shipped with every UNIX system. These applications are quite varied in
scope. There are general – purpose tools, text manipulation utilities (called filters), compilers and
interpreters, networked applications and system administration tools.

d) Pattern MatchingUNIX features very sophisticated pattern matching features. UNIX features elaborate
pattern matching schemes that use several characters from the Meta character set. The matching
isn’t confined to filenames only. Some of the most advanced and useful tools also use a special
expression called a regular expression that is framed with characters from the set.

e) Programming FacilityThe UNIX shell is also a programming language; it was designed for a programmer, not a
casual end user. It has all the necessary ingredients, like control structures, loops and variables,
that establish it as a powerful programming language in its own right.

f) DocumentationUNIX documentation is no longer the sore point it once was. Even though it is sometimes
uneven at most times the treatment is quite. The principal online help facility available is the
man command, which remains the most important reference for commands and their
configuration files. Thanks to O’Reilly & Associates, one can safely say that there’s no feature
of UNIX on which a separate textbook is not available.
Apart from the online documentation, there’s a vast ocean of UNIX resources available
on the internet. There are several newsgroups on UNIX where you can fire your queries in case
you are stuck with a problem – be it a problem related to shell programming or a network
configuration issue. The FAQ (Frequently Asked Questions) a document that addresses common
problems is also widely available on the Net. Then there are numerous articles published in
magazines and journals and lecture notes available by universities on their Web sites. UNIX is
easily tamed Operating System  

PROGRAMMING LANGUAGES

INTRODUCTION

Computers are machines. Unfortunately they cannot understand natural languages, such
as Hindi, English, Tamil, etc. that human beings speak and understand. Therefore, to give
instructions to computers, different languages have been developed. These languages are called
computer languages. To get a particular work done by computers, programmers write
instructions using these computer languages. Each computer language has its own vocabulary of
a natural language that we speak. Each natural language has its rules and grammar. Similarly,
each computer language too has its set of rules that are called as syntax. As computers are not
intelligent, we have to use the exact syntax rules of the computer language whenever we write
any computer program. Otherwise, the computer will not be able to understand our instructions.
Over the last few decades, several computer languages have developed. Different
computer languages are suitable for different applications. For example, COBOL (Common
business oriented Language) may be more suitable for business applications, whereas
FORTRAN may be more suitable for scientific or engineering applications. We can classify all
computer languages into three categories.

 PROGRAMMING LANGUAGES

Computer languages are classified into three categories:
1. Machine language
2. Assembly language:
3. High level languages:

 MACHINE LANGUAGE

The form in which information is denoted or represented by a combination of “1” and
“0”s is called machine language. Programs and data are ultimately represented in machine
language in memory and other hardware of the computer.
To start with computer programmers used machine language for programming. It was
tedious since each operation that the computer has to perform is denoted by a particular
combination of”1” s and”0”s.Also each computer had its own machine language code. One has
to remember all these codes to write a program.
While machine language had the drawbacks mentioned above, it was very efficient in
using computer circuits. There was no necessity for software to convert since we can directly
represent the machine language in the computer circuits without the necessity of conversion.

•  Advantages of Machine Language:

Even though machine languages are not a human friendly language, it offers following
advantages.a) Translation Free:Machine language is the only language that computers can directly execute without the
need for conversion. Even an application using high-level languages, has to be converted into
machine-readable form so that the computer can understand the instructions

First ProgrammerLady Lovelace Ada Augusta (officially the first programmer) suggested
binary numbers for computer storage instead of decimals. A British
mathematician, Alan Mathison Turing, was the first person to recognize that
programming in machine language is less time consuming. In 1952, John
von Neuman proposed to have new programs loaded from a magnetic tape to
read. With differences in magnetic polarities, it can mean either ON of OFF
states.
b) High Speed:Since no conversion is needed, the applications developed using machine language are
extremely fast. It is usually used for complex applications such as space control system, nuclear
reactors, and chemical processing.

• Disadvantages of Machine Language:

There are many disadvantages in using machine language to develop programs. Some of
these area) Machine Dependent:Every computer type differs from the other, based on its architecture. Hence, an
application developed for a particular type of computer may not run on the other type of
computer. This any prove costly as well as difficult for the organizations.

b) Complex Language:
Machine language is very difficult to read and write. Since all the data and instructions
must be converted to binary code, it is almost impossible to remember the instructions. A
programmer must specify each operation, and the specific locations for each piece of data and
instructions to be stored. It means that a programmer practically needs to be hardware expert to
have proper control over the machine language.

c) Error Prone:Since the programmer has to remember all the opcodes and the memory locations,
machine language is bound to be error prone. It requires a super human effort to keep track of
the logic of an problem and, therefore, results in frequent programming errors.

d) Tedious:Machine language poses real problems while modifying and correcting a program.
Sometimes the programming becomes too complex to modify and the programmer has to rewrite
the entire logic again. Therefore, it is very tedious and time-consuming, and since time is a
precious commodity, programming using the machine language tends to be costly. Due to its
overwhelming limitations, machine language is rarely used nowadays.

 ASSEMBLY LANGUAGE:As computer field advanced, computer scientists felt the necessity of making computer
programming easier. They invented computer languages that are easy to remember and use.
These languages called assembly language uses mnemonic codes. for Example: For adding two
quantities X and Y, You may code as follows.

ADD X YADD is called operation code that tells the computer what operation it has to perform. X
and Y are called operation addresses. These refer to the memory addresses where the quantities
you want to add are stored. X refers to the location of first quantity and Y the second quantity.
These are called symbolic address, since they do not refer to any fixed address. Software called
assembler translates this assembly language program into machine language program which you
can load into computer memory and execute.
When the program is loaded into memory for execution the symbolic addresses are
automatically converted into actual physical addresses of operands involved in an instruction.

•  Assembly language offers the following advantages:

a) The assembly language uses mnemonic codes, for programming. So it is easier for the
programmer to use assembly language than machine language for programming.b) The assemblers, in addition to translating the assembler language program into machine
language, list the program statements (called source code) and also the syntax errors that the
programmer committed.

• Assembly language has certain disadvantages too:

a) One has to spend considerable time in writing the assembly language program.b) An assembly language program has to be converted into machine language program using
assembly.c) While it is easier to use than the machine language one still has to remember the operation
codes for various operations.

HIGH LEVEL LANGUAGES:During 1960s computers started to gain popularity and it became necessary to develop
languages that were more like natural languages such as English so that a common user could
use the computer efficiently. Since assembly language required deep knowledge of computer
architecture, it demanded programming as well as hardware skills to use computers. Due to
computer’s widespread usage, early 1960s saw the emergence of the third generations
programming languages (3GL). Languages such as COBOL, FORTRAN, BASIC, and C are
examples of 3GLs and are considered high-level languages.

High level languages are similar to English language. Programs written using these
languages can be machine independent. A single high-level statement can substitute several
instructions in machine or assembly language. Unlike assembly and machine programs, highlevel programs may be used with different types of computers with little or no modification, thus
reducing the re-programming time.
In high-level language, programs are written in a sequence of statements to solve a
problem. For example, the following BASIC code snippet will calculate the sum of two numbers
LET X = 10
LET Y = 20
LET SUM = X + Y PRINT SUM
The first two statements store 10 in variable X (memory locations name) and 20 in
variable, Y, respectively. The third statement again creates a variable named SUM, which will
store the summation of X and Y value. Finally, the output is printed, that is, the value stored in
SUM is printed on the screen.

• Translating High-level Language to machine language:

Since computers understand only machine language, it is necessary to convert the highlevel language programs into machine language codes. This is achieved by using language
translators or language processors, generally known as compliers, interpreters or other routines
that accepts statements in one language and produces equivalent statements in another language.
a) Compiler:A compiler is a kind of translator that translates a program into another program, known
as target language. Usually, the term compiler is used for language translator of high-level
language into machine language. The complier replaces single high-level statement with a series
of machine language instruction. A compiler usually resides on a disk or the storage media.
When a program is to be complied, its complier is loaded into main memory. The compiler
stores the entire high-level program, scans it and translates the whole program into an equivalent
machine language program. During the translation process, the compiler reads the source
program and checks the syntax (grammatical) errors. If there is any error, the compiler generates
an error message, which is usually displayed on the screen. In case of errors, the compiler will
not create the object code until all the errors are rectified.

Once the program has been compiled, the resulting machine code is saved in an
executable file, which can be run on its own at any time. To be precise, once the executable is
generated, there is no need for the actual source code file. Anyway, it is worthwhile to keep the
source file(s) because if the source code is modified, it is necessary to recompile the program
again to regenerate the executable file containing amendments.


b) Interpreter:Unlike compilers, an interpreter translates a statement in a program and executes the
statement immediately, before translating the next source language statement. When an error is
encountered in the program, the execution of the program is halted and an error message is
displayed. Similar to compilers, every interpreted language such as BASIC and LISP has its
own interpreters.

•  Advantages of high-level languages:

High-level languages (HLL) are useful in developing complex software, as they support
complex data structures. It increases the programmer’s productivity (the number of lines of code
generated per hour). Unlike assembly language, the programmer does not need to learn the
instructions set of each computer being worked with. The various advantages of using high-level
languages are discussed below:

CompilersCompiler is a program which translates source code written in a particular
programming language into computer-readable machine code that can be directly
loaded and executed. For each high-level language, a separate compiler is
required. For example, a complier for C language cannot translate a program
written in FORTRAN. Hence, to execute both language programs, the host
computer must have the compilers of both languages.
a) Readability:Since high-level languages are closer to natural languages, they are easier to learn and
understand. In addition, a programmer does not need to be aware of computer architecture; even
a common man can use it without much difficulty. This is the main reason of HLL’s popularity.

b) Machine Independent:High-level language are machine independent in the sense that a program created using HLL
can be used on different platforms with very little or no change at all.

c) Easy Debugging:High-level languages include the support for ideas of abstraction so that programmers can
concentrate on finding the solution to the problem rapidly, rather than on low-level details of
data representation, which results in fewer errors. Moreover, the compilers and interpreters are
designed in such a way that they detect and point out the errors instantaneously.

d) Easier to Maintain:As compared to low-level languages, the programs written in HLL are easy to modify and
maintain because HLL programs are easier to understand.

e) Low Development Cost:High-level languages permit faster development of programs. Although a high-level
program may not be as efficient as an equivalent low-level program, but the savings in
programmer’s time generally outweighs the inefficiencies of the application. This is because the
cost of writing a program is nearly constant for each line of code, regardless of the language.
Thus, a high-level language, where each line of code translates to 10 machine instructions, costs
only a fraction as compared to program developed in a low-level language.

f) Easy Documentation: Since the statements written in HLL are similar to natural languages
they are easier to understand as compared to low-level languages.

• Disadvantages of high-level languages:

The main disadvantages of this language are:a) Poor Control on Hardware:High-level languages are developed to ease the pressure on programmers so that they do not
have to know the intricacies of hardware. As a result, sometimes the applications written in
high-level languages cannot completely harness the total power available at hardware level.

b) Less Efficient:The HLL applications are less efficient as far as computation time is concerned. This is
because, unlike low-level languages, high-level languages must be created and 

NETWORKING

INTRODUCTION

With standardized hardware and software, the microcomputers provide user-friendly
environment. It meets the computing requirements of most users. But, the need for interaction
with other computer users and with other computer systems for exchange of data etc., has
increased over the years. Networks are increasingly meeting this need. From the users’ point of
view the networks may be of two types: Local area network and Wide area network.

Computer networking is the process of inter connecting two or more computers so that
the users can communicate with each other, share resources and overcome other limitations of
stand-alone systems. The network can be established with a variety of combinations of
computers such as a net of only microcomputers, microcomputers and one or more
minicomputers and a set of microcomputers connected to a mainframe computer. The computers
in typical network are autonomous in the sense that they have processing capability independent
of the network.

 ADVANTAGES OF NETWORKING

The main advantages of networking are:

(i). Hardware resource sharing:Network enables sharing of expensive resources such as processor, storage space and
peripherals like modern, fax, and laser printer.

(ii). Sharing of databases:The network permits concurrent access to the same data file by many users in the
network. Thus, user in the sales department, production department, inventory department etc
share corporate databases.

(iii). Sharing of Software:Any user in a network can load and use the software installed on any of the computer of
file server in the network.

(iv). Communication between users:The Network users can communicate between them. E-mail facility can also be used for
communication.

(v). Decentralized data processing:In a network, the data processing can be decentralized by enabling local offices to capture
and store data, and generate information to meet most of their requirements a local level itself.

(vi) Security of data:In a networked environment the data is backed up with duplicate storage. Adequate
security measures are also put in place to product the data.

TYPES OF NETWORK

The networks can be classified into three; local area network (LAN), metropolitan area
network (MAN) and wide area network (WAN). They are explained in the following sections:

1. Wide Area Network (WAN)

WAN is made up of number of autonomous computers distributed over a wide
geographical area. WANs were originally developed in the late 1960s to enable communication
between computer centers and sharing of hardware, software and other communication facilities.
WAN can be implemented using private or public networks. In a private network an
organization takes on lease telephone lines to connect such sites into a network. It is also
possible to connect computers in different locations using microwave or satellite transmission.
Public networks are installed by the Government owned telecommunication agencies. WAN
spans large geographic distances. It is also called long-haul network. WAN is usually operated
at lower speeds then MAN and involves delay.

Most organizations use private networks for communication. Society for Worldwide Inter bank Financial Transactions (SWIFT), a non-profit organization of banks, owns a private network. The network exchanges financial transactions between the participating financial
institutions, about 3000 in number in over 60 countries. The terminals of these participating
banks are hooked with SWIFT’s access centers. The network offers data communication service
24 hours a day, 7 days a week.

INDONET, NICNET, SBINET and WELCOMENET are some of the private network in
India. CMC’s INDONET offers e-mail service to customers for a fee. NICNET is a network of
National Informatics Center that connects all the district headquarters in the country. SBINET is
a private network of State Bank of India and connects its branches across the country.
WELCOMNET connects the hotels of the Welcome Group.

• Features of Wide Area Network

A wide area network (WAN) is used to connect LANs and nodes that are separated by
great physical distance. Generally speaking it is larger version of LAN with several differences:
1. It operates by means of the international telephone network
2. Unlike LANs which owned by their users, WANs operate on public and leased
telephone lines provided by licensed common carriers, or by other means such satellite
and microwave, which are regulated by government agencies.
3. Data transmission is somewhere slower.
4. The WAN compose any of the following system configurations:
5. Single nodes
6. Clusters
7. LANs

Suppose a company has its central headquarters in Coimbatore and the Coimbatore site
contains all departments and equipment for product manufacturing prod distribution, accounting,
and sales. The information pertaining to these operations is tracked by a single centralized
database system. As the company becomes more profitable and expands, it established additional
sales offices on Mumbai and Delhi. Each sales office maintains its own system to record and
track customer orders for its region. At the same time the two sites are linked to the mode at
corporate headquarters and relay each order shipment and inventory and invoice processing.

•  Advantages of WAN

The integration of the local nodes into the distributed database linked by the WAN
provides the following advantages:
1. The WAN allows access to database at remote sites, enabling exchange of data.
2. If a remote node fails, remaining nodes on the network can still exchange data.
3. If the network fails, the local mode can still access its own database.
4. The data used on daily basis by the sales offices resides at the local site, making it easier to
retrieve quickly.
5. The local offices can maintain the data more effectively. The corporate office can access the
data as needed.
6. As a site's database grows larger, its system's storage capacity can be easily upgraded without
affecting the transfer of data between other nodes on network.
One of the most significant aspects of a wide area network when comparing it with
freedom of a local area network is the involvement of a public telecommunications authority.
Regardless of whether the network is made up from system, the controlling authority is almost
always the public authority. In order to protect their equipment and employees, the authority lays
down rules, which must be observed by anyone connecting to their lines. In most countries
stringent requirements are also imposed on the characteristics of the data transmissions.

2. Metropolitan Area Network (MAN)Metropolitan area network covers a wider area than a local area network. Usually MAN
covers a large metropolitan city and is a scaled down version of wide area network. It operates
at high speeds over distances sufficient for a metropolitan area.

3. Local Area Network (LAN)A LAN is a system of interconnected microcomputers, sharing common resources like
disks, printers etc., and links a number of computers workstations) together to allow many
people to use the same software and data files. Each user in such a multi-user environment
accesses the resources through his microcomputer workstation. The network operating system
integrates all the network components and makes operation smooth and transparent. LAN works
in restricted geographical area such as within a large building or offices within a few kilometers.
The LAN is an interconnection of computers that need to communicate with each other in a
limited geographical area. The network may have other sharable devices attached such as fax,
laser printers and copiers. The network includes a central facility with huge storage capacity for
the requirements of the organization. It also has a network operating system for managing the
network.

• Types of LAN:

Local area networks are mainly of two types: Client/ Server LAN and Peer-to-Peer LAN.

a) Client / Server LANClient Server LAN has servers and clients. The server is a computer that manages shared
resources: hardware as well as software and data. It is usually a powerful computer with large
RAM and secondary storage capacity. The LAN has a number of microcomputers, called
clients, the request the server for services. The LAN may have many servers each specializing in
one area of service such as file server, printer server, database server etc. A file server stores
program and data files. A database server stores data and a printer server controls printers on the
local area network.

b) Peer-to-Peer LAN:In a Peer-to-Peer LAN every computer is equal in status and functioning. All the
computers on the network are capable of communicating independently with any other computer
on the network without using a server. Thus, any computer on the network can access data and
programs stored on any other computer. The peer-to-peer LAN is less expensive than
client/server LAN. But at the same time this LAN may be slower than a client/server LAN.

 LAN TopologyThe design of network requires selection of a particular topology and an architecture for
the interconnection of network component.
Topology refers to the way the computers are physically connected into the network. The
network architecture includes the specifications of the components that can be connected to the
network. IBM’s Systems Network Architecture (SNA) is an example of vendor developed
network architecture. Such network architecture specifies network components such as
terminals, workstations, printers, cluster controllers, host computer and communications
controllers.
There area a number of network topologies. Of them ring, star and bus are popular network
topologies.

a) Star Topology:

In star network the nodes are connected to a central computer called the host computer.
The nodes cannot communicate directly. Each node can communicate with the host computer.
The host computer takes the message and routes it to the other node or nodes.
The host is the main computer to which other nodes are connected by communication
links. The host computer is responsible for the overall functioning of the network. The node
may be a microcomputer, terminal or any other device like storage device, printer etc.,

In a star network centralization of control over the network resources is easy. It is also
possible to network minicomputer or mainframe with other microcomputers and dumb terminals.
It eliminates single point failure of a common wire. If one of the host computers fails, it does not
usually affect the others in the network. But the hub becomes a central point of failure in a ring
network. If the host computer breaks down, the entire network breaks down.

STAR TOPOLOGY

b) Ring Topology:

In a ring network the computers can communicate directly with each other and also with
the central computer. The nodes are connected to a line that is closed like a loop. The ring
network is more reliable than star network. Even if the central computer in the network fails, the
other computers can continue to communicate with each other.

c) Bus Topology:

A bus network configures computers to a single non-looping channel. The computers
connected to the network share the same bus or communication channel. Bus wiring is easy and
needs much less wring for small segments.
Old Ethernet bus wiring is prone to cable failure. If the bus wiring connection is broken
at any point, the entire network fails.

d) Hybrid Network:

In most cases, instead of a single topology, a combination of topologies may be used for
greater flexibility and reliability. Hybrid network combines features of Star, Ring and Bus
network:

 Features of LANThe features of LAN include the following
a) Limited geographical area say within a few kilometers.
b) Common communication link for sharing information, software and peripheral devices
without regard to proximity of user to such resources on the network.
c) High transmission capability.
d) Low error rate as the network contains built-in component for detecting for system errors.
e) Private ownership by the user.
f) Not subject to regulation by the telecom service.

LAN interconnects computers and computers and components within a limited
geographical area. Such LANs are normally set up within a single site can have one or more
business complex, a hospital, an office- building etc. The site can have one or more buildings but
they should not be too for a way, say less then5 kilometers. A LAN can also include a variety of
computer systems and devices such as workstations, microcomputer, file servers, plotters,
scanners, graphic terminals and printers.

A large personal computer or mini computer serves as the LAN’s hub. A high capacity
hand disk is attached to the hub as data files and software are stored on the network file server.
The users can load the software on the file server and retrieve data files for processing. The
output can be directed to the printer attached to the LAN.

Any the communication network that meets most or all of the following characteristics
can be classified as LAN,:
a) All the devices on the network share a common transmission medium, that is, the cable and/
or the controller.
b) The devices connected to the network can operate independent of the network.
c) Any device connected to it can communicate with any other device on the network, and
d) The network is capable of supporting heavy data traffic over short distances compared to
telecommunication network.
e) The network covers a limited area usually a few kilometers in radius or a single site like a
university campus, an office or a factory.
 LAN ComponentsThe components of LAN are File server, workstation, network operating system, LAN
cable, Active and Passive hubs etc.a) WorkstationIt is a single-user microcomputer with high power communication facilities. It can
exchange message with other workstations or file server.
Workstations can be of two types: user workstation and server workstation. User
workstation is a microcomputer on the network, which is used to access the network. Service
workstation performs service to process other workstations on the network. User workstation
normally does not process requests from other workstations. Server workstation makes available
all sharable network resources to other workstations. More than one server workstations may be
added to the network such as printer server and fileserver. Normally the server workstation is
the most powerful workstation. Server workstation may be dedicated or non-dedicated. In case
of dedicated workstation, it is not available for other user applications. Non-dedicated server
workstation doubles as an individual workstation and at the same time performs network-related
functions.

b) File ServerFile server is actually a process running on a computer that provides the clients access to
files on that computer. The term is loosely applied to mean computer that runs file server
software. In this sense, it is a powerful computer with special software to serve files to other
workstations on the network. The files, which may be program files or data files, are
simultaneously shared by a number of workstations. Novell Netware is a popular network
operating system.

c) GatewayThe gateway assists in communicating between LANs. A workstation may be dedicated
to serve as gateway. This is required particularly when two networks with different technologies
have to communicate with each other. Gateway may also be used to connect LAN with a
mainframe computer.

d) Network Interface UnitThe network interface is a printed circuit board installed in the microcomputer. It may be
called network card, network adapter or network interface unit. It connects the workstations
functionally and physically with the network.

e) Active HubHub is an electronic device to which multiple computers are attached usually using
twisted pair cables. Active hub is a powered distribution point with active devices that drive
distant nodes up to one kilometer away. It can connect up to eight nodes on the network. The
maximum distance carried by an active hub is about 2000 ft.

f) Passive HubThis hub is a distribution point that does not use power or active devices in a network to
connect up to four nodes within a short distance. The maximum distance covered by a passive
hub is nearly 300 ft.

g) LAN CableLAN requires superior cable capable of transferring data at high speed. Coaxial cables or
fiber optic cables may be used for networking computer.
h) Network Operating System (NOS)

The NOS integrates all the network components. The NOS facilitates file and print
serving along with other functions like communications and e-mail between workstations. In
most LANs the NOS exists along with the computer’s operating system.. The computer’s
operating system processes the system requests first and processes them if they can be done with
the workstation resources. If it is not a local request, meaning that the network resources have to
be used, the request is transferred to NOS for carrying out. Thus, the NOS is responsible for
controlling access to data, storage space and sharing of other peripheral resources.

i) Applications SoftwareAnother component of LAN is application software. It has to be ensured that the
application software works in the multi-user environment.

j) ProtocolsData transmission between devices requires protocol. Protocols are sets of rules and
procedures to control the data transmission between computer and other devices. They are
common technical guidelines for communication between devices. They specify the order in
which signals will be transferred, the signal for completion of transfer etc. Only Devices using
the same protocol can communicate directly. Both the sending and receiving devices must use
the same protocol for effecting communication. For communication between devices using
different protocols requires intermediate interpretation device or software.The protocol performs the following functions:
a) Set up a link with the other device in the communication.b) Identify the component to other components in the communication (sending device’s
channel ID)c) Send and interpret the datad) Provide a continuous feedback on data transmission like data is not being received and
understood.e) Request for retransmission of garbled data.f) Engage recovery procedure when error occurs.g) Provide an acceptable way of terminating transmission so that all devices have completed the
process.
The protocol is embedded in communication software designed to use a particular protocol.
The user need not bother about the protocol as the components involved in the communication
perform the protocol matching. The data communication protocols are of two main types:
asynchronous and synchronous. The synchronous protocol permits continuous data
transmission. The devices in communication must be synchronized with the other. The
transmission is governed by a time interval and not by start-stop bits. For example, clock, in the
modern, sets the time interval  

COMPUTER-RELATED JOBS

COMPUTER-RELATED JOBS  

INTRODUCTIONThe fast spread of IT has generated a need for highly trained workers to design and
develop new information systems and to integrate new technologies in them. It is creating the
need for professional workers who can fulfill the high performance standards in the technologybased industries. The IT professional plan, design, develops, support, and manage the strategies
and adopt them to fulfill basic objectives of them firm. The rapidly changing technology
requires the employees to have more skills and education. The companies look out for IT
professionals who not only have sound technical knowledge of the subject but also have sound
interpersonal and communication skills.

 COMPUTER-RELATED JOBS

1. Programmer:

A programmer is a person who writes the code for a computer program. Computer
programs are the instructions given to the computer, telling the computer what to do, which
information to identify, access and process. The programmers write programs, depending on the
specifications given by the systems’ analysts and software engineers. After the completion of
the design process, the programmer’s job is to convert that design into a series of instructions
that the computer can follow. These instructions are coded in a programming language such as
C, C++, and Java, and then tested to ensure that the instructions are correct and produce the
required result. Programmers perform functions such as system designing, and its related services. They are involved in coding of a project and the successful implementation of the
developed system.

There are tow types of programmers – application programmers and system
programmers. The application programmers code programs for a specific task (application) in
the organization. On the other hand, the systems programmers code programs for controlling
and maintaining the computer system software.

2. System analyst:

A systems analyst plans, designs, develops, and implements new systems or applies the
existing system resources to perform additional operations. Most of the systems analysts work
with specific type of system like business, accounting, finance, science or engineering and so on.
Some systems analysts are also known as system developers or system architects.
A system analyst determines the problem in the system by discussing it with the
managers and users before starting an assignment. They study the information needs of the
organization to determine the changes that are required to deliver a solution to the problems of
users. To design a system, the systems analysts specify the inputs required by the system, plan
the processing steps and finalize the output to meet the user’s requirements. Next, the systems
analyst determines the hardware and software needed to set up the system.

Systems analysts prepare the specifications, flowcharts, and process diagrams for the
computer programmers to follow, and then work with the programmers to debut, and to rectify
and errors in the system. They also check the initial use of the system and organize tests to
check the working of the system to ensure that it works as required of planned. Systems analysts
who perform more intricate testing of products are referred to as software equality assurance
analysts. They not only perform tests but also diagnose the problems, suggest solutions and
checks whether the program requirements have been met or not. The analysts, who design, test
and evaluate the Internet, Intranet, local area network (LAN), wide area network (WAN) and
other data communications system are called network and data communications analysts.

3. Network administrator

A network administrator is a person who installs, configures, and supports the local area
network, wide area network, the Internet system or the segment of a network system in an
organization. Every network in an organization requires at least one network administrator.
Network administrators perform the functions such as installation, configuration, maintenance of
computers, and networking of equipment. They also check and ensure the availability of
network to all the users. They supervise the support of other networks and plan, coordinate and
implement network security measures.

4. Database administratorA database administrator (DBA) is an individual who is responsible for the storage of
data, management of the database, and implementation of the database management system.
They work with database management systems software and determine ways to organize and
store data. They identify user requirements, set up the computer databases, and test and organize
the modifications to the systems. They also ensure the performance of the system in the
organization, understand the platform on which the database is running and adds new users to the
system. DBA is responsible for maintaining data integrity, back up systems and database
security.

5. Web designers

A web designer is an individual who provides an architectural structure for the effective
communication of clients’ content by logically organizing the information and making it
accessible. With the rapid growth of the Internet, many jobs relating to design, development,
and maintenance of the web sites and servers have cropped up in the market. The web designer
controls all aspects of design and programming of elements of text and visual design. They are
responsible for maintaining all technical aspects of a web site, including its performance issues
such as speed of access and approving the content of the web site. Web designers create the
artistic feel of the web site, facilitate navigation, and make content on the web site accessible to
the users.

6. Information security analystAn information security analyst is an individual who performs highly complex analysis
and technical tasks involving assignment and co-ordination of measures to provide information
assurance, event detection, and rapid response across various environments of the enterprise.
Information security analysts design, implement and support integration of information security
solutions including security architectures, firewall administration, integrating security products,
and developing and coordinating security implementation plans. They provide technical support
on security projects that involve a wide range of issues including secure electronic data traffic,
network security, platform and data security and privacy. They review and contribute to the
security activities of business application and development project plans across all business
units.

7. Business process outsourcingBusiness Processing Outsourcing (BPO) refers to a decision to assign to another party
some or all non-core processes. The main motive of BPO is to allow the company to invest more
time, money, and human resources into core activities and building strategies, which helps in
company growth. The BPO jobs include various sectors like finance, accounts, customer support,
IT services, medicines, among other. Today, the global market is highly competitive and ever
changing. A company must focus on improving productivity and even cut down costs. There
fore, many tasks that use precious time, resources and energy, are being outsourced. BPOs, or
the units to which work is being outsourced are flexible, quicker, and cheaper and very efficient
in performance of the work