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Sundar B. N. Assistant Professor
Paper VI Fundamentals of Information Technology
Karnataka State Open University
2015 August QP Solved
1) Define Information technology
Information technology (IT) is the use of any computers, storage, networking and other physical
devices, infrastructure and processes to create, process, store, secure and exchange all forms
of electronic data. Typically, IT is used in the context of enterprise operations as opposed to
personal or entertainment technologies. The commercial use of IT encompasses both computer
technology and telephony.
The term information technology was coined by the Harvard Business Review, in order to make
a distinction between purpose-built machines designed to perform a limited scope of functions
and general-purpose computing machines that could be programmed for various tasks. As the IT
industry evolved from the mid-20th
century, computing capability advanced while device cost
and energy consumption fell lower, a cycle that continues today when new technologies emerge
2) Expand ENIAC.
ENIAC, in full Electronic Numerical Integrator and Computer, the first programmable
general-purpose electronic digital computer, built during World War II by the United States.
American physicist John Mauchly, American engineer J. Presper Eckert, Jr., and their colleagues
at the Moore School of Electrical Engineering at the University of Pennsylvania led a
government-funded project to build an all-electronic computer. Under contract to the army and
under the direction of Herman Goldstine, work began in early 1943 on ENIAC. The next year,
mathematician John von Neumann began frequent consultations with the group.
3) State the Different types of ROM.
ROM- Read Only Memory
As the name suggests, ROM can only be read by the processor. New data cannot be written into
ROM. Data to be stored into ROM is written during the manufacturing phase itself. They contain data
that does not need to be altered, like booting sequence of a computer or algorithmic tables for
mathematical applications. ROM is slower and hence cheaper than RAM. It retains its data even
when power is switched off, i.e. it is non-volatile. ROM cannot be altered the way RAM can be but
technologies are available to program these types of ROMs –
PROM (Programmable ROM) PROM - can be programmed using a special hardware device called
PROM programmer or PROM burner.
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EPROM (Erasable Programmable ROM)- EPROM can be erased and then programmed using
special electrical signals or UV rays. EPROMs that can be erased using UV rays are called
UVEPROM and those that can be erased using electrical signals are called EEPROM. However,
handling electric signals is easier and safer than UV rays.
Cache Memory Small piece of high speed volatile memory available to the processor for fast
processing is called cache memory. Cache may be a reserved portion of main memory, another chip
on CPU or an independent high speed storage device. Cache memory is made of fast speed SRAMs.
The process of keeping some data and instructions in cache memory for faster access is
called caching. Caching is done when a set of data or instructions is accesses again and again.
Whenever the processor needs any piece of data or instructions, it checks the cache first. If it is
unavailable there, then the main memory and finally secondary memory is accessed. As cache has
very high speed, time spent in accessing it every time is negligible as compared to time saved if data
indeed is in the cache. Finding data or instruction in cache is called cache hit.
4) What is System Software?
The system software is a collection of programs designed to operate, control, and extend the
processing capabilities of the computer itself. System software is generally prepared by the computer
manufacturers. These software products comprise of programs written in low-level languages, which
interact with the hardware at a very basic level. System software serves as the interface between the
hardware and the end users.
Some examples of system software are Operating System, Compilers, Interpreter, Assemblers, etc.
Here is a list of some of the most prominent features of a system software −
 Close to the system
 Fast in speed
 Difficult to design
 Difficult to understand
 Less interactive
 Smaller in size
 Difficult to manipulate
 Generally written in low-level language
5) What is file Organization?
File Organization refers to the logical relationships among various records that constitute the file,
particularly with respect to the means of identification and access to any specific record. In simple
terms, Storing the files in certain order is called file Organization. File Structure refers to the format
of the label and data blocks and of any logical control record.
Objective of file organization
 It contains an optimal selection of records, i.e., records can be selected as fast as possible.
 To perform insert, delete or update transaction on the records should be quick and easy.
 The duplicate records cannot be induced as a result of insert, update or delete.
Sundar B. N. Assistant Professor
 For the minimal cost of storage, records should be stored efficiently.
6) What is Modem?
Modem is abbreviation for Modulator – De-modulator. Modems are used for data transfer
from one computer network to another computer network through telephone lines. The
computer network works in digital mode, while analog technology is used for carrying
massages across phone lines.
Modulator converts information from digital mode to analog mode at the transmitting end
and de-modulator converts the same from analog to digital at receiving end. The process of
converting analog signals of one computer network into digital signals of another computer
network so they can be processed by a receiving computer is referred to as digitizing.
When an analog facility is used for data communication between two digital devices called Data
Terminal Equipment (DTE), modems are used at each end. DTE can be a terminal or a
computer.
Types of Modems
• Modems can be of several types and they can be categorized in a number of ways.
• Categorization is usually based on the following basic modem features:
1. Directional capacity: half duplex modem and full duplex modem.
2. Connection to the line: 2-wire modem and 4-wire modem.
3. Transmission mode: asynchronous modem and synchronous modem.
7) What is Packet Switching Network?
Packet switching is the transfer of small pieces of data across various networks. These data
chunks or “packets” allow for faster, more efficient data transfer.
Often, when a user sends a file across a network, it gets transferred in smaller data packets, not in
one piece. For example, a 3MB file will be divided into packets, each with a packet header that
includes the origin IP address, the destination IP address, the number of packets in the entire data
file, and the sequence number.
Types of Packet Switching
There are two major types of packet switching:
Connectionless Packet Switching. This classic type of packet switching includes multiple
packets, each individually routed. This means each packet contains complete routing
information—but it also means different paths of transmission and out-of-order delivery are
possible, depending on the fluctuating loads on the network’s nodes (adapters, switches and
routers) at the moment. This kind of packet switching is sometimes called datagram switching.
Sundar B. N. Assistant Professor
Each packet in connectionless packet switching includes the following information in its header
section:
 Source address
 Destination address
 Total number of packets
 Sequence number (Seq#) for reassembly
Once the packets reach their destination via various routes, the receiving devices rearrange them
to form the original message.
Connection-Oriented Packet Switching. In connection-oriented packet switching, also called
virtual circuit switching or circuit switching, data packets are first assembled and then numbered.
They then travel across a predefined route, sequentially. Address information is not needed in
circuit switching, because all packets are sent in sequence.
8) State any two Transmission Media.
The transmission medium can be defined as a pathway that can transmit information from a
sender to a receiver. Transmission media are located below the physical layer and are controlled
by the physical layer. Transmission media are also called communication channels.
Transmission media are of two types −
 Guided Transmission Medium
 Unguided Transmission Medium
1. Guided Media:
It is also referred to as Wired or Bounded transmission media. Signals being transmitted are
directed and confined in a narrow pathway by using physical links.
There are 3 major types of Guided Media:
(i) Twisted Pair Cable –
It consists of 2 separately insulated conductor wires wound about each other. Generally, several
such pairs are bundled together in a protective sheath. They are the most widely used
Transmission Media
(ii) Coaxial Cable –
It has an outer plastic covering containing 2 parallel conductors each having a separate insulated
protection cover. Coaxial cable transmits information in two modes: Baseband mode(dedicated
cable bandwidth) and Broadband mode(cable bandwidth is split into separate ranges). Cable TVs
and analog television networks widely use Coaxial cables.
(iii) Optical Fibre Cable –
It uses the concept of reflection of light through a core made up of glass or plastic. The core is
surrounded by a less dense glass or plastic covering called the cladding. It is used for
transmission of large volumes of data.
The cable can be unidirectional or bidirectional. The WDM (Wavelength Division Multiplexer)
supports two modes, namely unidirectional and bidirectional mode.
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2. Unguided Media:
It is also referred to as Wireless or Unbounded transmission media.No physical medium is
required for the transmission of electromagnetic signals.
(i) Radiowaves –
These are easy to generate and can penetrate through buildings. The sending and receiving
antennas need not be aligned. Frequency Range:3KHz – 1GHz. AM and FM radios and cordless
phones use Radiowaves for transmission.
Further Categorized as (i) Terrestrial and (ii) Satellite.
(ii) Microwaves –
It is a line of sight transmission i.e. the sending and receiving antennas need to be properly
aligned with each other. The distance covered by the signal is directly proportional to the height
of the antenna. Frequency Range:1GHz – 300GHz. These are majorly used for mobile phone
communication and television distribution.
(iii) Infrared –
Infrared waves are used for very short distance communication. They cannot penetrate through
obstacles. This prevents interference between systems. Frequency Range:300GHz – 400THz. It
is used in TV remotes, wireless mouse, keyboard, printer, etc.
9) What is Protocol?
Protocol Definition: It is a digital language through which we communicate with others on
the Internet. protocol meaning is that it a set of mutually accepted and implemented
rules at both ends of the communications channel for the proper exchange of information.
By adopting these rules, two devices can communicate with each other and can
interchange information. We can’t even think of using the Internet without Protocols.
Each protocol is defined in different terms and different use with unique name. Message travel
from sender to receiver via a medium (The medium is the physical path over which a message
travels) using a protocol.
‘Protocols’ are developed by industry wide organizations. All data of protocols are stored in
binary information. Protocol language is a mixture of bits, characters, integers, etc.
Each of it has its own access method of exchanging data over a computer network, such as
LAN, Internet, Intranet, etc. One of the most common and known protocol example is HTTP,
that is used over the world wide web. there are different protocols used in internet that are
• TCP/IP (Transmission Control Protocol/Internet Protocol)
• ARP (Address Resolution Protocol)
• DHCP (Dynamic Host Configuration Protocol)
• DNS (Domain Name System)
• FTP (File Transfer Protocol)
Sundar B. N. Assistant Professor
HTTP is an application-layer protocol that is used for transferring files on the internet. It is used
by web browsers and servers use to communicate
TCP
Transmission control protocol is used for communication over a network. In TCP data is broken
down into small packets and then sent to the destination. However, IP is making sure packets
are transmitted to the right address.
Internet Protocol (IP)
IP is also working with TCP. It is an addressing Protocol. IP addresses packets route them and
show different nodes and network Unless it reaches its right destination. The IP protocol is
developed in 1970.
FTP
File transfer protocol is basically used for transferring files to different networks. There may be
a mass of files such as text files, multimedia files, etc. This way of file transfer is quicker than
other methods.
10) State the parts of E-mail.
Email, short for "electronic mail," is one of the most widely used features of the Internet, along with
the web. It allows you to send and receive messages to and from anyone with an email address,
anywhere in the world.
Email uses multiple protocols within the TCP/IP suite. For example, SMTP is used to send messages,
while the POP or IMAP protocols are used to retrieve messages from a mail server. When you
configure an email account, you must define your email address, password, and the mail servers used
to send and receive messages.
Parts of an email message
An email message consists of the following general components:
Headers
The message headers contain information concerning the sender and recipients. The exact
content of mail headers can vary depending on the email system that generated the message.
Generally, headers contain the following information:
 Subject. Subject is a description of the topic of the message and displays in most email
systems that list email messages individually. A subject line could be something like
"2010 company mission statement" or, if your spam filtering application is too lenient,
"Lose weight fast!!! Ask me how."
 Sender (From). This is the sender's Internet email address. It is usually presumed to be
the same as the Reply-to address, unless a different one is provided.
 Date and time received (On). The date and time the message was received.
 Reply-to. This is the Internet email address that will become the recipient of your reply if
you click the Reply button.
 Recipient (To:). First/last name of email recipient, as configured by the sender.
Sundar B. N. Assistant Professor
 Recipient email address. The Internet mail address of the recipient, or where the
message was actually sent.
 Attachments. Files that are attached to the message.
Body
The body of a message contains text that is the actual content, such as "Employees who are
eligible for the new health care program should contact their supervisors by next Friday if they
want to switch." The message body also may include signatures or automatically generated text
that is inserted by the sender's email system.
11) Trace the History and Developments of Computers.
A BRIEF COMPUTER HISTORY
The computer as we know it today had its beginning with a 19th century English mathematics
professor name Charles Babbage. He designed the Analytical Engine and it was this design that the
basic framework of the computers of today are based on. Generally speaking, computers can be
classified into three generations. Each generation lasted for a certain period of time,and each gave us
either a new and improved computer or an improvement to the existing computer.
First generation: 1937 – 1946 - In 1937 the first electronic digital computer was built by Dr. John V.
Atanasoff and Clifford Berry. It was called the Atanasoff-Berry Computer (ABC). In 1943 an
electronic computer name the Colossus was built for the military. Other developments continued until
in 1946 the first general– purpose digital computer, the Electronic Numerical Integrator and
Computer (ENIAC) was built. It is said that this computer weighed 30 tons, and had 18,000 vacuum
tubes which was used for processing. When this computer was turned on for the first time lights dim
in sections of Philadelphia. Computers of this generation could only perform single task, and they had
no operating system.
Second generation: 1947 – 1962 - This generation of computers used transistors instead of vacuum
tubes which were more reliable. In 1951 the first computer for commercial use was introduced to the
public; the Universal Automatic Computer (UNIVAC 1). In 1953 the International Business Machine
(IBM) 650 and 700 series computers made their mark in the computer world. During this generation
of computers over 100 computer programming languages were developed, computers had memory
and operating systems. Storage media such as tape and disk were in use also were printers for output.
Third generation: 1963 - present - The invention of integrated circuit brought us the third
generation of computers. With this invention computers became smaller, more powerful more reliable
and they are able to run many different programs at the same time. In1980 Microsoft Disk Operating
System (MS-Dos) was born and in 1981 IBM introduced the personal computer (PC) for home and
office use. Three years later Apple gave us the Macintosh computer with its icon driven interface and
the 90s gave us Windows operating system.
As a result of the various improvements to the development of the computer we have seen the
computer being used in all areas of life. It is a very useful tool that will continue to experience new
development as time passes.
Development of Computers
Although the development of digital computers is rooted in the abacus and early mechanical
calculating devices, Charles Babbage is credited with the design of the first modern computer,
the analytical engine, during the 1830s. Vannevar Bush built a mechanically operated device,
Sundar B. N. Assistant Professor
called a differential analyzer, in 1930; it was the first general-purpose analog computer.
John Atanasoff constructed the first electronic digital computing device in 1939; a full-scale
version of the prototype was completed in 1942 at Iowa State College (now Iowa State Univ.). In
1943 Conrad Zuse built the Z3, a fully operational electromechanical computer.
During World War II, the Colossus was developed for British codebreakers; it was the first
programmable electronic digital computer. The Mark I, or Automatic Sequence Controlled
Calculator, completed in 1944 at Harvard by Howard Aiken, was the first machine to execute
long calculations automatically, while the first all-purpose electronic digital computer, ENIAC
(Electronic Numerical Integrator And Calculator), which used thousands of vacuum tubes, was
completed in 1946 at the Univ. of Pennsylvania. UNIVAC (UNIVersal Automatic Computer)
became (1951) the first computer to handle both numeric and alphabetic data with equal facility;
intended for business and government use, this was the first widely sold commercial computer.
First-generation computers were supplanted by the transistorized computers (see transistor ) of
the late 1950s and early 60s, second-generation machines that were smaller, used less power, and
could perform a million operations per second. They, in turn, were replaced by the third-
generation integrated-circuit machines of the mid-1960s and 1970s that were even smaller and
were far more reliable. The 1970s, 80s, and 90s were characterized by the development of the
microprocessor and the evolution of increasingly smaller but powerful computers, such as the
personal computer and personal digital assistant (PDA), which ushered in a period of rapid
growth in the computer industry.
The World Wide Web was unveiled in 1990, and with the development of graphical web browser
programs in succeeding years the Web and the Internet spurred the growth of general purpose
home computing and the use of computing devices as a means of social interaction.
Smartphones, which integrate a range of computer software with a cellular telephone that now
typically has a touchscreen interface, date to 2000 when a PDA was combined with a cellphone.
Although computer tablets date to the 1990s, they only succeeded commercially in 2010 with the
introduction of Apple's iPad, which built on software developed for smartphones. The increasing
screen size on some smartphones has made them the equivalent of smaller computer tablets,
leading some to call them phablets.
 Introduction
 Development of Computers
 Digital Computers
 Analog Computers
 Bibliography
12) Explain in detail the application of IT in Library and Information work.
APPLICATION OF INFORMATION TECHNOLOGY IN LIBRARY
The library is the main information centre which can make use of the fat development IT for the
benefits of mankind as a whole. The librarian’s preference of IT should include all those technologies
which are expected to be used in the library activities/ operations and other library services for
collection, processing, storage, retrieval and dissemination of recorded information, the fast
Sundar B. N. Assistant Professor
developing information technologies have showered almost every areas of application including
libraries. In case of libraries, these are good use in the following environments.
a) Library Management: Library management includes the following activities which will certainly
be geared up by the use of these fast IT developments: Classification, Cataloguing, Indexing,
Database creation, Database Indexing.
b) Library Automation: Library automation is the concept of reducing the human intervention in all
the library services so that any user can receive the desired information with the maximum comfort
and at the lowest cot. Major areas of the automation can be classified into two -organization o f all
library databases and all housekeeping operations of library.
c) Library Networking: Library networking means a group pf Libraries and information Centres are
interconnected for some common pattern or design for information exchange and communication
with a view to improve efficiency.
d) Audio-Video Technology: It includes photography, microfilms, microfiches, audio and tapes,
printing, optical disk etc.
e) Technical Communication: Technical Communication consisting of technical writing, editing,
publishing, DTP systems etc
CLASSIFICATION OF INFORMATION TECHNOLOGY BASED SERVICES Information
technology based services can organize on the basis of three main criteria. I. Apparatus and
Amenities II. Customer Services III. Electronic Sources
I. Apparatus and Amenities:
The equipments and facilities available in the library are illuminating in the following headings.
a) Computers: Computer-based technologies have become dominant forces to shape and reshape the
products and services the academic library has to offer. The success of the IT enabled services in the
library is based on the efficiency of the equipment provided in the library i.e. most modern
technology, not on the basis of number of equipments.
b) OPAC: An Online Public Access Catalog (OPAC) is an online database of materials held by a
library or group of libraries. Users search a library catalog principally to locate books and other
material physically located at a library.
c) Union Catalogue: A union catalog is a combined library catalog describing the collections of a
number of libraries. Union catalogs have been created in a range of media, including book format,
microform, cards and more recently, networked electronic databases. Union catalogs are useful to
librarians, as they assist in locating and requesting materials from other libraries through interlibrary
loan service .
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d) CD-ROM: Presents a state-of-the-art review of the applications of CD-ROMs in academic
libraries, embracing all aspects of library involvement and staffing implications. Concludes that CD-
ROM is having a huge impact on the way academic libraries function and the services they offer to
their users .
e) Scanner: In computing, an image scanner—often abbreviated to just scanner— is a device that
optically scans images, printed text, handwriting, or an object, and converts it to a digital image..
Mechanically driven scanners that move the document are typically used for large-format documents,
where a flatbed design would be impractical.
f) RFID: Radio frequency identification is a term used for technologies utilizing radio waves for
identifying individual items automatically. The most common way is storing a serial number
identifying a product and related information on a microchip attached to an antenna. RFID is used
very similar to bar codes.
g) Tele text: Teletext is a television information retrieval service developed in the United Kingdom
in the early 1970s. It offers a range of text-based information, typically including national,
international and sporting news, weather and TV schedules. Teletext information is broadcast in the
vertical blanking interval between image frames in a broadcast television signal .
h) Facsimile: A facsimile is a copy or reproduction of an old book, manuscript, map, art, or other
item of historical value that is as true to the original source as possible. It differs from other forms of
reproduction by attempting to replicate the source as accurately as possible in terms of scale, color,
condition, and other material qualities. For books and manuscripts, this also entails a complete copy
of all pages; hence an incomplete copy is a "partial facsimile".
i) Photocopy: A photocopier is a machine that makes paper copies of documents and other visual
images quickly and cheaply. Most current photocopiers use a technology called xerography, a dry
process using heat. Photocopying is widely used in library .
II. Customer Services
a) Document delivery services: The Document Delivery Service (DDS) delivers copies of journal
articles and book chapters from participating Libraries. Fees apply for most Document Delivery
Services. To fulfill the information needs of the end user through information/document supply is a
document delivery service. This service is provided on No Profit - No Loss Basis and Expected to be
prompt .
b) Interlibrary loan: Inter library loan means a cooperative arrangement among libraries by which
one library may borrow material from another library. In other words a loan of library materials by
one library to another library.
c) Indexing and abstracting services: a method which is used to retrieve information form a table in
memory or a file on a direct access store or the art of compiling an index. The preparation of
abstracts, usually in a limited field, by an individual, an industrial organization of r restricted use or a
Sundar B. N. Assistant Professor
commercial organization: the abstracts being published and supplied regularly to subscribers. Also
the organization producing the abstracts. Such services may be either comprehensive or selective.
d) Chat services: Online chat may refer to any kind of communication over the Internet, that offers
an instantaneous transmission of text-based messages from sender to receiver, hence the delay for
visual access to the sent message shall not hamper the flow of communications in any of the
directions. Online chat may address as well point-to-point communications as well as multicast
communications from one sender to many receivers .
e) CAS: The purpose of a current-awareness service is to inform the users about new acquisitions in
their libraries. Public libraries in particular have used display boards and shelves to draw attention to
recent additions, and many libraries produce complete or selective lists for circulation to patrons.
Some libraries have adopted a practice of selective dissemination of information.
f) SDI: Selective dissemination of information ("SDI") was originally a phrase related to library and
information science. SDI refers to tools and resources used to keep a user informed of new resources
on specified topics. Selective Dissemination of Information (SDI) was a concept first described by
Hans Peter Luhn of IBM in the 1950's.
g) Scanned copies: A scanning service for material not available electronically, which is held by the
Library. This includes articles from journals and chapters from books. Users of the service should be
aware that we operate within the restrictions of the Copyright Act .
h) Bulletin board services: A Bulletin Board System, or BBS, is a computer system running
software that allows users to connect and log in to the system using a terminal. Once logged in, a user
can perform functions such as uploading and downloading software and data, reading news and
bulletins, and exchanging messages with other users, either through electronic mail or in public
message boards.
i) Electronic services and e- resources: The important fact is convincing many libraries to move
towards digital e-resources, which are found to be less expensive and more useful for easy access.
This is especially helpful to distant learners who have limited time to access the libraries from outside
by internet access to commonly available electronic resources, mainly CD-ROM, OPACs, E-Journals,
E-Books, ETD and Internet, which are replacing the print media.
j) Digital library: A digital library is a library in which collections are stored in digital formats and
accessible by computers. The digital content may be stored locally, or accessed remotely via
computer networks. A digital library is a type of information retrieval system.
III. Electronic Sources
a) Audiovisual materials: The Audiovisual Collection contains a wide range of audiovisual material
to support the research and study needs of staff and students .
b) Internet: With the advent of digital revolution, communication has become easier and faster and
decision are mad instantaneously. The internet which is the latest among the superhighways has cut
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down the distance and made it easier to have access to information to all people at all places and at all
the times.
c) Library website: Library website helps to recognize the facilities and information sources
available in the library. In most of the library website online catalogue is included. Online catalogue
helps to ascertain a client whether the information is available in the library.
d) Database: A database is an organized collection of data for one or more purposes, usually in
digital form. The data are typically organized to model relevant aspects of reality, in a way that
supports processes requiring the information.
13) What is application software? Explain the features of MS Excel.
Application Software
Application software products are designed to satisfy a particular need of a particular environment.
All software applications prepared in the computer lab can come under the category of Application
software.
Application software may consist of a single program, such as Microsoft's notepad for writing and
editing a simple text. It may also consist of a collection of programs, often called a software package,
which work together to accomplish a task, such as a spreadsheet package.
Examples of Application software are the following −
 Payroll Software
 Student Record Software
 Inventory Management Software
 Income Tax Software
 Railways Reservation Software
 Microsoft Office Suite Software
 Microsoft Word
 Microsoft Excel
 Microsoft PowerPoint
Features of application software are as follows −
 Close to the user
 Easy to design
 More interactive
 Slow in speed
 Generally written in high-level language
 Easy to understand
 Easy to manipulate and use
 Bigger in size and requires large storage space
What is Excel?
Microsoft Excel is a helpful and powerful program for data analysis and documentation. It is a
spreadsheet program, which contains a number of columns and rows, where each intersection of
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a column and a row is a “cell.” Each cell contains one point of data or one piece of information.
By organizing the information in this way, you can make information easier to find, and
automatically draw information from changing data.
Features of Microsoft Excel
1. Add Header and Footer
MS Excel allows us to keep the header and footer in our spreadsheet document.
2. Find and Replace Command
MS Excel allows us to find the needed data (text and numbers) in the workbook and also replace
the existing data with a new one.
3. Password Protection
It allows the user to protect their workbooks by using a password from unauthorized access to
their information.
4. Data Filtering
Filtering is a quick and easy way to find and work with a subset of data in a range. A filtered
range displays only the rows that meet the criteria you specify for a column. MS Excel provides
two commands for filtering ranges:
• AutoFilter; which includes filter by selection, for simple criteria
• Advanced Filter; for more complex criteria
5. Data Sorting
Data sorting is the process of arranging data in some logical order. MS Excel allows us to sort
data either in ascending or descending order.
6. Built-in formulae
MS Excel has got many built-in formulae for sum, average, minimum, etc. We can use those
formulae as per our needs.
7. Create different charts (Pivot Table Report)
MS Excel allows us to create different charts such as bar graph, pie- charts, line graphs, etc. This
helps us to analyze and compare data very easily.
8. Automatically edits the result
MS Excel automatically edits the result if any changes are made in any of the cells.
9. Formula Auditing
Using formula auditing we can graphically display or trace the relationships between cells and
formulas with blue arrows. We can trace the precedents (the cells that provide data to a specific
cell) or the dependents (the cells that depend on the value in a specific cell).
14) Explain in detail the different devices used in the network.
There are different types of electronic devices are used in networking which are known as network
devices or network equipment. In a computer network, network devices are mainly used for
transmitting and receiving the data quickly and securely in between computers, fax machines,
printers, etc. These devices may be intra network or internetwork. There are some devices are
installed on the device such as RJ45 connector otherwise NIC card, whereas some devices are part of
the network namely switch, router, etc. These devices are specific devices, handles digital or
electrical connections to perform their exclusive roles very efficiently. This article discusses an
overview of network devices and their working.
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What are Network Devices?
Definition: The devices which are used for communication between different hardware’s used in
the computer network are known as network devices. These devices are also known as physical
devices, networking hardware, and network equipment otherwise computer networking devices.
In a computer network, each network device plays a key role based on their functionality, and
also works for different purposes at different segments.
Types of Network Devices
There are different types of network devices used in a computer network which include the
following.
 Network Hub
 Network Switch
 Modem
 Network Router
 Bridge
 Repeater
Network Hub
The network hub is one kind of networking device in a computer network, used to communicate
with various network hosts and also for data transferring. The transferring of data in a computer
network can be done in the form of packets. Whenever the data processing can be done from a
host to a network hub, then the data can transmit to all the connected ports. Similarly, all the
ports identify the data path which leads to inefficiencies & wastage. Because of this working, a
network hub cannot be so safe and secure. In addition, copying the data packets on all the ports
will make the hub slower which leads to the utilize of the network switch.
Network Switch
Similar to a hub, this is also working at the layer in the LAN and a switch is more clever
compare with a hub. As the hub is used for data transferring, whereas a switch is used for
filtering & forwarding the data. So this is the more clever technique to deal with the data packets.
Whenever a data packet is obtained from the interfaces in the switch, then the data packet can be
filtered & transmits to the interface of the proposed receiver. Due to this reason, a switch
maintains a content addressable memory table to maintain system configuration as well as
memory. This table is also named as FIB (forwarding information base) otherwise forwarding
table.
Modem
A modem is the most important network device and it is used daily in our life. If we notice the
internet connection to homes was given with the help of a wire. then wire carries internet data
from one place to another. But, every computer gives digital or binary data in the form of zeros
& ones
The full form of the modem is a modulator and a demodulator. So it modulates as well as
demodulates the signal among the computer and a telephone line because the computer generates
digital data whereas the telephone line generates an analog signal.
Network Router
A network router is one kind of network device in a computer network and it is used for routing
traffic from one network to another. These two networks could be private to a public company
network. For example, here a router is considered as traffic police at the junction, he directs
dissimilar traffic networks to dissimilar directions.
Bridge
Sundar B. N. Assistant Professor
A Bridge in the computer network is used to unite two or more network segments. The main
function of a bridge in network architecture is to store as well as transmit frames among the
various segments. Bridges use MAC (Media Access Control) hardware for transferring frames.
These are also used for connecting two physical local area networks to a larger logical local area
network. In the OSI model, bridges work at the data link & physical layers to divide the
networks from larger to smaller by controlling the data flow between the two. In recent years,
bridges are replaced by switches to provide more functionality.
Repeater
The operating of a repeater can be done at the physical layer. The main function of this device is
to reproduce the signal on a similar network before the signal gets weak otherwise damaged. The
significant point to be noted regarding these devices is that they do not strengthen the signal.
Whenever the signal gets weak, then they reproduce it at the actual strength. A repeater is a two-
port device.
Gateway
Generally, a gateway performs at the session & transport layers in the OSI model. Gateways
offer conversion between networking technologies like OSI (Open System Interconnection)
& TCP/IP. Because of this, these are connected to two or many autonomous networks, where
each network has its own domain name service, routing algorithm, topology, protocols, and
procedures of network administration & policies
Gateways execute all the functions of routers. Actually, a router with additional conversion
functionality is a gateway, so the conversion between various network technologies is known as
a protocol converter.
Brouter
The Brouter is also called a bridging router and the main function of this is to combine the
features of both router & bridge and router. It performs either at the network layer or the data
link layer. When it works as a router, it is used for routing packets across networks whereas it
works as a bridge; it is used for filtering LANs traffic.
15) Write an essay on Internet Services.
What is Internet?
The internet is the wider network that allows computer networks around the world run by companies,
governments, universities and other organisations to talk to one another. The result is a mass of
cables, computers, data centres, routers, servers, repeaters, satellites and wifi towers that allows
digital information to travel around the world.
It is that infrastructure that lets you order the weekly shop, share your life on Facebook, stream
Outcast on Netflix, email your aunt in Wollongong and search the web for the world’s tiniest cat.
In order to connect to the Internet, you need to use an Internet service. Internet service provides a
way for data to be transferred from Internet servers to your computer. An Internet service provider
is a company that provides access to the Internet. Most ISPs require you to subscribe in order to use
their services, but there are ways to connect to the Internet for free. Some of the most common
ways to connect to the Internet are dial-up, DSL, cable and wireless services.
Internet Services allows us to access huge amount of information such as text, graphics, sound and
software over the internet. Following diagram shows the four different categories of Internet Services.
Sundar B. N. Assistant Professor
a) Communication Services
There are various Communication Services available that offer exchange of information with
individuals or groups. The following table gives a brief introduction to these services:
Electronic Mail Used to send electronic message over the internet
Telnet Used to log on to a remote computer that is attached to internet
Newsgroup Offers a forum for people to discuss topics of common interests.
Internet Relay Chat (IRC) Allows the people from all over the world to communicate in real time
Mailing Lists Used to organize group of internet users to share common information through e-mail
Internet Telephony (VoIP) Allows the internet users to talk across internet to any PC equipped to
receive the call
Instant Messaging Offers real time chat between individuals and group of people. Eg. Yahoo
messenger, MSN messenger.
b) Information Retrieval Services
There exist several Information retrieval services offering easy access to information present on the
internet. The following table gives a brief introduction to these services:
File Transfer Protocol (FTP) Enable the users to transfer files.
Archie It’s updated database of public FTP sites and their content. It helps to search a file by its
name
Gopher Used to search, retrieve, and display documents on remote sites.
Very Easy Rodent Oriented Netwide Index to Computer Achieved (VERONICA)
VERONICA is gopher based resource. It allows access to the information resource stored on
gopher’s servers.
c) Web Services
Web services allow exchange of information between applications on the web. Using web services,
applications can easily interact with each other.
The web services are offered using concept of Utility Computing.
d) World Wide Web (WWW)
WWW is also known as W3. It offers a way to access documents spread over the several servers
over the internet. These documents may contain texts, graphics, audio, video, hyperlinks. The
hyperlinks allow the users to navigate between the documents.
Dial-up
At one time, a dial-up account was the most common way to access the Internet. Accessing a dial-
up connection requires you to use a landline telephone connection and a modem attached or
connected to your computer. In order to establish the connection, you literally must instruct your
computer to dial a telephone number provided by the ISP. A dial-up connection is the least
Sundar B. N. Assistant Professor
expensive and slowest way to connect to the Internet. Another disadvantage of dial-up is that you
cannot make or receive phone calls while connected to the Internet. Some dial-up ISPs offer free,
limited Internet access.
DSL
A digital subscriber line is another way to connect to the Internet through a telephone connection,
but the quality and speed of the connection is significantly greater than a dial-up connection. And
unlike a dial-up connection, DSL is "always on," which means you can still make and receive
telephone calls with your land line telephone. One thing to consider is that DSL Internet services
are not available in all areas.
Cable
A cable Internet connection is established by subscribing to an account with a local cable television
provider and connecting a cable modem to your computer. Cable Internet connections are capable
of transmitting data faster than a DSL connection. Like DSL, a cable Internet connection is always
on and does not interfere with your telephone access. The cost of a subscription with a cable ISP
can be equal to or greater than a DSL subscription.
Wireless
A wireless Internet connection does not require your desktop or notebook computer to be
connected to telephone or cable wires. You simply need a modem and an account with a wireless
Internet provider. In many areas, you can access a wireless connection free of charge. Many coffee
shops, restaurants, public libraries and schools offer free wireless Internet connection.
Video Conferencing Video conferencing or Video teleconferencing is a method of communicating
by two-way video and audio transmission with help of telecommunication technologies.
16) Hard Disk.
Hard Disk Drive - Hard disk drive is made up of a series of circular disks called platters arranged
one over the other almost ½ inches apart around a spindle. Disks are made of non-magnetic material
like aluminum alloy and coated with 10-20 nm of magnetic material.
Standard diameter of these disks is 14 inches and they rotate with speeds varying from 4200 rpm
(rotations per minute) for personal computers to 15000 rpm for servers. Data is stored by magnetizing
or demagnetizing the magnetic coating. A magnetic reader arm is used to read data from and write
data to the disks. A typical modern HDD has capacity in terabytes (TB).
A hard drive fits inside a computer case and is firmly attached with the use of braces and screws
to prevent it from being jarred as it spins. Typically it spins at 5,400 to 15,000 RPM. The disk
moves at an accelerated rate, allowing data to be accessed immediately. Most hard drives operate
on high speed interfaces using serial ATA (SATA) or serial attached technology. When the
platters rotate, an arm with a read/write head extends across the platters. The arm writes new data
to the platters and reads new data from them. Most hard drives use enhanced integrated drive
electronics (EIDE) including cables and connectors to the motherboard. All data is stored
magnetically, allowing information to be saved when power is shut off.
Hard drives need a read only memory (ROM) controller board to instruct the read/write heads
how, when and where to move across the platters. Hard drives have disks stacked together and
Sundar B. N. Assistant Professor
spin in unison. The read/write heads are controlled by an actuator, which magnetically reads
from and writes to the platters. The read/write heads float on a film of air above the platters. Both
sides of the platters are used to store data. Each side or surface of one disk is called a head, with
each one divided into sectors and tracks. All tracks are the same distance from the center of the
disk. Collectively they comprise one cylinder. Data is written to a disk starting at the furthest
track. The read/write heads move inward to the next cylinder once the first cylinder is filled.
A hard drive is divided into one of more partitions, which can be further divided into logical
drives or volumes. Usually a master boot record (MBR) is found at the beginning of the hard
drive and contains a table of partition information. Each logical drive contains a boot record, a
file allocation table (FAT) and a root directory for the FAT file system
17) Flow Chart.
What is a Flowchart?
Flowchart is a graphical representation of an algorithm. Programmers often use it as a program-
planning tool to solve a problem. It makes use of symbols which are connected among them to
indicate the flow of information and processing.
The process of drawing a flowchart for an algorithm is known as “flowcharting”.
1. Terminal: The oval symbol indicates Start, Stop and Halt in a program’s logic flow. A
pause/halt is generally used in a program logic under some error conditions. Terminal is
the first and last symbols in the flowchart.
2. Input/Output: A parallelogram denotes any function of input/output type. Program
instructions that take input from input devices and display output on output devices are
indicated with parallelogram in a flowchart.
3. Processing: A box represents arithmetic instructions. All arithmetic processes such as
adding, subtracting, multiplication and division are indicated by action or process symbol.
4. Decision Diamond symbol represents a decision point. Decision based operations such as
yes/no question or true/false are indicated by diamond in flowchart.
5. Connectors: Whenever flowchart becomes complex or it spreads over more than one page,
it is useful to use connectors to avoid any confusions. It is represented by a circle.
6. Flow lines: Flow lines indicate the exact sequence in which instructions are executed.
Arrows represent the direction of flow of control and relationship among different symbols
of flowchart.
7.
18) Indexed sequential access file organization
 Indexed sequential access file combines both sequential file and direct access file
organization.
 In indexed sequential access file, records are stored randomly on a direct access device
such as magnetic disk by a primary key.
Sundar B. N. Assistant Professor
 This file have multiple keys. These keys can be alphanumeric in which the records are
ordered is called primary key.
 The data can be access either sequentially or randomly using the index. The index is
stored in a file and read into memory when the file is opened.
Advantages of Indexed sequential access file organization
 In indexed sequential access file, sequential file and random file access is possible.
 It accesses the records very fast if the index table is properly organized.
 The records can be inserted in the middle of the file.
 It provides quick access for sequential and direct processing.
 It reduces the degree of the sequential search.
Disadvantages of Indexed sequential access file organization
 Indexed sequential access file requires unique keys and periodic reorganization.
 Indexed sequential access file takes longer time to search the index for the data access or
retrieval.
 It requires more storage space.
 It is expensive because it requires special software.
 It is less efficient in the use of storage space as compared to other file organizations.
19) Transmission Modes.
Transmission mode refers to the mechanism of transferring of data between two devices
connected over a network. It is also called Communication Mode. These modes direct the
direction of flow of information. There are three types of transmission modes. They are:
 Simplex Mode
 Half duplex Mode
 Full duplex Mode
SIMPLEX Mode
In this type of transmission mode, data can be sent only in one direction i.e. communication is
unidirectional. We cannot send a message back to the sender. Unidirectional communication is
done in Simplex Systems where we just need to send a command/signal, and do not expect any
response back.
Examples of simplex Mode are loudspeakers, television broadcasting, television and remote,
keyboard and monitor etc.
Sundar B. N. Assistant Professor
HALF DUPLEX Mode
Half-duplex data transmission means that data can be transmitted in both directions on a signal
carrier, but not at the same time.
For example, on a local area network using a technology that has half-duplex transmission, one
workstation can send data on the line and then immediately receive data on the line from the
same direction in which data was just transmitted. Hence half-duplex transmission implies a
bidirectional line (one that can carry data in both directions) but data can be sent in only one
direction at a time.
Example of half duplex is a walkie- talkie in which message is sent one at a time but messages
are sent in both the directions.
FULL DUPLEX Mode
In full duplex system we can send data in both the directions as it is bidirectional at the same
time in other words, data can be sent in both directions simultaneously.
Example of Full Duplex is a Telephone Network in which there is communication between two
persons by a telephone line, using which both can talk and listen at the same time.
In full duplex system there can be two lines one for sending the data and the other for receiving data.
20) TCP/IP.
The Internet Protocol (IP) is the address system of the Internet and has the core function of delivering
packets of information from a source device to a target device. IP is the primary way in which
network connections are made, and it establishes the basis of the Internet. IP does not handle packet
ordering or error checking. Such functionality requires another protocol, typically TCP.The TCP/IP
relationship is similar to sending someone a message written on a puzzle through the mail. The
message is written down and the puzzle is broken into pieces. Each piece then can travel through a
different postal route, some of which take longer than others. When the puzzle pieces arrive after
traversing their different paths, the pieces may be out of order. The Internet Protocol makes sure the
pieces arrive at their destination address. The TCP protocol can be thought of as the puzzle assembler
on the other side who puts the pieces together in the right order, asks for missing pieces to be resent,
and lets the sender know the puzzle has been received.
TCP maintains the connection with the sender from before the first puzzle piece is sent to after the
final piece is sent.IP is a connectionless protocol, which means that each unit of data is individually
addressed and routed from the source device to the target device, and the target does not send an
acknowledgement back to the source. That’s where protocols such as the Transmission Control
Protocol (TCP) come in. TCP is used in conjunction with IP in order to maintain a connection
between the sender and the target and to ensure packet order.
For example, when an email is sent over TCP, a connection is established and a 3-way handshake is
made. First, the source send an SYN “initial request” packet to the target server in order to start the
dialogue. Then the target server then sends a SYN-ACK packet to agree to the process. Lastly, the
source sends an ACK packet to the target to confirm the process, after which the message contents
can be sent. The email message is ultimately broken down into packets before each packet is sent out
into the Internet, where it traverses a series of gateways before arriving at the target device where the
group of packets are reassembled by TCP into the original contents of the email.

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Fundamental of Information Technology

  • 1. Sundar B. N. Assistant Professor Paper VI Fundamentals of Information Technology Karnataka State Open University 2015 August QP Solved 1) Define Information technology Information technology (IT) is the use of any computers, storage, networking and other physical devices, infrastructure and processes to create, process, store, secure and exchange all forms of electronic data. Typically, IT is used in the context of enterprise operations as opposed to personal or entertainment technologies. The commercial use of IT encompasses both computer technology and telephony. The term information technology was coined by the Harvard Business Review, in order to make a distinction between purpose-built machines designed to perform a limited scope of functions and general-purpose computing machines that could be programmed for various tasks. As the IT industry evolved from the mid-20th century, computing capability advanced while device cost and energy consumption fell lower, a cycle that continues today when new technologies emerge 2) Expand ENIAC. ENIAC, in full Electronic Numerical Integrator and Computer, the first programmable general-purpose electronic digital computer, built during World War II by the United States. American physicist John Mauchly, American engineer J. Presper Eckert, Jr., and their colleagues at the Moore School of Electrical Engineering at the University of Pennsylvania led a government-funded project to build an all-electronic computer. Under contract to the army and under the direction of Herman Goldstine, work began in early 1943 on ENIAC. The next year, mathematician John von Neumann began frequent consultations with the group. 3) State the Different types of ROM. ROM- Read Only Memory As the name suggests, ROM can only be read by the processor. New data cannot be written into ROM. Data to be stored into ROM is written during the manufacturing phase itself. They contain data that does not need to be altered, like booting sequence of a computer or algorithmic tables for mathematical applications. ROM is slower and hence cheaper than RAM. It retains its data even when power is switched off, i.e. it is non-volatile. ROM cannot be altered the way RAM can be but technologies are available to program these types of ROMs – PROM (Programmable ROM) PROM - can be programmed using a special hardware device called PROM programmer or PROM burner.
  • 2. Sundar B. N. Assistant Professor EPROM (Erasable Programmable ROM)- EPROM can be erased and then programmed using special electrical signals or UV rays. EPROMs that can be erased using UV rays are called UVEPROM and those that can be erased using electrical signals are called EEPROM. However, handling electric signals is easier and safer than UV rays. Cache Memory Small piece of high speed volatile memory available to the processor for fast processing is called cache memory. Cache may be a reserved portion of main memory, another chip on CPU or an independent high speed storage device. Cache memory is made of fast speed SRAMs. The process of keeping some data and instructions in cache memory for faster access is called caching. Caching is done when a set of data or instructions is accesses again and again. Whenever the processor needs any piece of data or instructions, it checks the cache first. If it is unavailable there, then the main memory and finally secondary memory is accessed. As cache has very high speed, time spent in accessing it every time is negligible as compared to time saved if data indeed is in the cache. Finding data or instruction in cache is called cache hit. 4) What is System Software? The system software is a collection of programs designed to operate, control, and extend the processing capabilities of the computer itself. System software is generally prepared by the computer manufacturers. These software products comprise of programs written in low-level languages, which interact with the hardware at a very basic level. System software serves as the interface between the hardware and the end users. Some examples of system software are Operating System, Compilers, Interpreter, Assemblers, etc. Here is a list of some of the most prominent features of a system software −  Close to the system  Fast in speed  Difficult to design  Difficult to understand  Less interactive  Smaller in size  Difficult to manipulate  Generally written in low-level language 5) What is file Organization? File Organization refers to the logical relationships among various records that constitute the file, particularly with respect to the means of identification and access to any specific record. In simple terms, Storing the files in certain order is called file Organization. File Structure refers to the format of the label and data blocks and of any logical control record. Objective of file organization  It contains an optimal selection of records, i.e., records can be selected as fast as possible.  To perform insert, delete or update transaction on the records should be quick and easy.  The duplicate records cannot be induced as a result of insert, update or delete.
  • 3. Sundar B. N. Assistant Professor  For the minimal cost of storage, records should be stored efficiently. 6) What is Modem? Modem is abbreviation for Modulator – De-modulator. Modems are used for data transfer from one computer network to another computer network through telephone lines. The computer network works in digital mode, while analog technology is used for carrying massages across phone lines. Modulator converts information from digital mode to analog mode at the transmitting end and de-modulator converts the same from analog to digital at receiving end. The process of converting analog signals of one computer network into digital signals of another computer network so they can be processed by a receiving computer is referred to as digitizing. When an analog facility is used for data communication between two digital devices called Data Terminal Equipment (DTE), modems are used at each end. DTE can be a terminal or a computer. Types of Modems • Modems can be of several types and they can be categorized in a number of ways. • Categorization is usually based on the following basic modem features: 1. Directional capacity: half duplex modem and full duplex modem. 2. Connection to the line: 2-wire modem and 4-wire modem. 3. Transmission mode: asynchronous modem and synchronous modem. 7) What is Packet Switching Network? Packet switching is the transfer of small pieces of data across various networks. These data chunks or “packets” allow for faster, more efficient data transfer. Often, when a user sends a file across a network, it gets transferred in smaller data packets, not in one piece. For example, a 3MB file will be divided into packets, each with a packet header that includes the origin IP address, the destination IP address, the number of packets in the entire data file, and the sequence number. Types of Packet Switching There are two major types of packet switching: Connectionless Packet Switching. This classic type of packet switching includes multiple packets, each individually routed. This means each packet contains complete routing information—but it also means different paths of transmission and out-of-order delivery are possible, depending on the fluctuating loads on the network’s nodes (adapters, switches and routers) at the moment. This kind of packet switching is sometimes called datagram switching.
  • 4. Sundar B. N. Assistant Professor Each packet in connectionless packet switching includes the following information in its header section:  Source address  Destination address  Total number of packets  Sequence number (Seq#) for reassembly Once the packets reach their destination via various routes, the receiving devices rearrange them to form the original message. Connection-Oriented Packet Switching. In connection-oriented packet switching, also called virtual circuit switching or circuit switching, data packets are first assembled and then numbered. They then travel across a predefined route, sequentially. Address information is not needed in circuit switching, because all packets are sent in sequence. 8) State any two Transmission Media. The transmission medium can be defined as a pathway that can transmit information from a sender to a receiver. Transmission media are located below the physical layer and are controlled by the physical layer. Transmission media are also called communication channels. Transmission media are of two types −  Guided Transmission Medium  Unguided Transmission Medium 1. Guided Media: It is also referred to as Wired or Bounded transmission media. Signals being transmitted are directed and confined in a narrow pathway by using physical links. There are 3 major types of Guided Media: (i) Twisted Pair Cable – It consists of 2 separately insulated conductor wires wound about each other. Generally, several such pairs are bundled together in a protective sheath. They are the most widely used Transmission Media (ii) Coaxial Cable – It has an outer plastic covering containing 2 parallel conductors each having a separate insulated protection cover. Coaxial cable transmits information in two modes: Baseband mode(dedicated cable bandwidth) and Broadband mode(cable bandwidth is split into separate ranges). Cable TVs and analog television networks widely use Coaxial cables. (iii) Optical Fibre Cable – It uses the concept of reflection of light through a core made up of glass or plastic. The core is surrounded by a less dense glass or plastic covering called the cladding. It is used for transmission of large volumes of data. The cable can be unidirectional or bidirectional. The WDM (Wavelength Division Multiplexer) supports two modes, namely unidirectional and bidirectional mode.
  • 5. Sundar B. N. Assistant Professor 2. Unguided Media: It is also referred to as Wireless or Unbounded transmission media.No physical medium is required for the transmission of electromagnetic signals. (i) Radiowaves – These are easy to generate and can penetrate through buildings. The sending and receiving antennas need not be aligned. Frequency Range:3KHz – 1GHz. AM and FM radios and cordless phones use Radiowaves for transmission. Further Categorized as (i) Terrestrial and (ii) Satellite. (ii) Microwaves – It is a line of sight transmission i.e. the sending and receiving antennas need to be properly aligned with each other. The distance covered by the signal is directly proportional to the height of the antenna. Frequency Range:1GHz – 300GHz. These are majorly used for mobile phone communication and television distribution. (iii) Infrared – Infrared waves are used for very short distance communication. They cannot penetrate through obstacles. This prevents interference between systems. Frequency Range:300GHz – 400THz. It is used in TV remotes, wireless mouse, keyboard, printer, etc. 9) What is Protocol? Protocol Definition: It is a digital language through which we communicate with others on the Internet. protocol meaning is that it a set of mutually accepted and implemented rules at both ends of the communications channel for the proper exchange of information. By adopting these rules, two devices can communicate with each other and can interchange information. We can’t even think of using the Internet without Protocols. Each protocol is defined in different terms and different use with unique name. Message travel from sender to receiver via a medium (The medium is the physical path over which a message travels) using a protocol. ‘Protocols’ are developed by industry wide organizations. All data of protocols are stored in binary information. Protocol language is a mixture of bits, characters, integers, etc. Each of it has its own access method of exchanging data over a computer network, such as LAN, Internet, Intranet, etc. One of the most common and known protocol example is HTTP, that is used over the world wide web. there are different protocols used in internet that are • TCP/IP (Transmission Control Protocol/Internet Protocol) • ARP (Address Resolution Protocol) • DHCP (Dynamic Host Configuration Protocol) • DNS (Domain Name System) • FTP (File Transfer Protocol)
  • 6. Sundar B. N. Assistant Professor HTTP is an application-layer protocol that is used for transferring files on the internet. It is used by web browsers and servers use to communicate TCP Transmission control protocol is used for communication over a network. In TCP data is broken down into small packets and then sent to the destination. However, IP is making sure packets are transmitted to the right address. Internet Protocol (IP) IP is also working with TCP. It is an addressing Protocol. IP addresses packets route them and show different nodes and network Unless it reaches its right destination. The IP protocol is developed in 1970. FTP File transfer protocol is basically used for transferring files to different networks. There may be a mass of files such as text files, multimedia files, etc. This way of file transfer is quicker than other methods. 10) State the parts of E-mail. Email, short for "electronic mail," is one of the most widely used features of the Internet, along with the web. It allows you to send and receive messages to and from anyone with an email address, anywhere in the world. Email uses multiple protocols within the TCP/IP suite. For example, SMTP is used to send messages, while the POP or IMAP protocols are used to retrieve messages from a mail server. When you configure an email account, you must define your email address, password, and the mail servers used to send and receive messages. Parts of an email message An email message consists of the following general components: Headers The message headers contain information concerning the sender and recipients. The exact content of mail headers can vary depending on the email system that generated the message. Generally, headers contain the following information:  Subject. Subject is a description of the topic of the message and displays in most email systems that list email messages individually. A subject line could be something like "2010 company mission statement" or, if your spam filtering application is too lenient, "Lose weight fast!!! Ask me how."  Sender (From). This is the sender's Internet email address. It is usually presumed to be the same as the Reply-to address, unless a different one is provided.  Date and time received (On). The date and time the message was received.  Reply-to. This is the Internet email address that will become the recipient of your reply if you click the Reply button.  Recipient (To:). First/last name of email recipient, as configured by the sender.
  • 7. Sundar B. N. Assistant Professor  Recipient email address. The Internet mail address of the recipient, or where the message was actually sent.  Attachments. Files that are attached to the message. Body The body of a message contains text that is the actual content, such as "Employees who are eligible for the new health care program should contact their supervisors by next Friday if they want to switch." The message body also may include signatures or automatically generated text that is inserted by the sender's email system. 11) Trace the History and Developments of Computers. A BRIEF COMPUTER HISTORY The computer as we know it today had its beginning with a 19th century English mathematics professor name Charles Babbage. He designed the Analytical Engine and it was this design that the basic framework of the computers of today are based on. Generally speaking, computers can be classified into three generations. Each generation lasted for a certain period of time,and each gave us either a new and improved computer or an improvement to the existing computer. First generation: 1937 – 1946 - In 1937 the first electronic digital computer was built by Dr. John V. Atanasoff and Clifford Berry. It was called the Atanasoff-Berry Computer (ABC). In 1943 an electronic computer name the Colossus was built for the military. Other developments continued until in 1946 the first general– purpose digital computer, the Electronic Numerical Integrator and Computer (ENIAC) was built. It is said that this computer weighed 30 tons, and had 18,000 vacuum tubes which was used for processing. When this computer was turned on for the first time lights dim in sections of Philadelphia. Computers of this generation could only perform single task, and they had no operating system. Second generation: 1947 – 1962 - This generation of computers used transistors instead of vacuum tubes which were more reliable. In 1951 the first computer for commercial use was introduced to the public; the Universal Automatic Computer (UNIVAC 1). In 1953 the International Business Machine (IBM) 650 and 700 series computers made their mark in the computer world. During this generation of computers over 100 computer programming languages were developed, computers had memory and operating systems. Storage media such as tape and disk were in use also were printers for output. Third generation: 1963 - present - The invention of integrated circuit brought us the third generation of computers. With this invention computers became smaller, more powerful more reliable and they are able to run many different programs at the same time. In1980 Microsoft Disk Operating System (MS-Dos) was born and in 1981 IBM introduced the personal computer (PC) for home and office use. Three years later Apple gave us the Macintosh computer with its icon driven interface and the 90s gave us Windows operating system. As a result of the various improvements to the development of the computer we have seen the computer being used in all areas of life. It is a very useful tool that will continue to experience new development as time passes. Development of Computers Although the development of digital computers is rooted in the abacus and early mechanical calculating devices, Charles Babbage is credited with the design of the first modern computer, the analytical engine, during the 1830s. Vannevar Bush built a mechanically operated device,
  • 8. Sundar B. N. Assistant Professor called a differential analyzer, in 1930; it was the first general-purpose analog computer. John Atanasoff constructed the first electronic digital computing device in 1939; a full-scale version of the prototype was completed in 1942 at Iowa State College (now Iowa State Univ.). In 1943 Conrad Zuse built the Z3, a fully operational electromechanical computer. During World War II, the Colossus was developed for British codebreakers; it was the first programmable electronic digital computer. The Mark I, or Automatic Sequence Controlled Calculator, completed in 1944 at Harvard by Howard Aiken, was the first machine to execute long calculations automatically, while the first all-purpose electronic digital computer, ENIAC (Electronic Numerical Integrator And Calculator), which used thousands of vacuum tubes, was completed in 1946 at the Univ. of Pennsylvania. UNIVAC (UNIVersal Automatic Computer) became (1951) the first computer to handle both numeric and alphabetic data with equal facility; intended for business and government use, this was the first widely sold commercial computer. First-generation computers were supplanted by the transistorized computers (see transistor ) of the late 1950s and early 60s, second-generation machines that were smaller, used less power, and could perform a million operations per second. They, in turn, were replaced by the third- generation integrated-circuit machines of the mid-1960s and 1970s that were even smaller and were far more reliable. The 1970s, 80s, and 90s were characterized by the development of the microprocessor and the evolution of increasingly smaller but powerful computers, such as the personal computer and personal digital assistant (PDA), which ushered in a period of rapid growth in the computer industry. The World Wide Web was unveiled in 1990, and with the development of graphical web browser programs in succeeding years the Web and the Internet spurred the growth of general purpose home computing and the use of computing devices as a means of social interaction. Smartphones, which integrate a range of computer software with a cellular telephone that now typically has a touchscreen interface, date to 2000 when a PDA was combined with a cellphone. Although computer tablets date to the 1990s, they only succeeded commercially in 2010 with the introduction of Apple's iPad, which built on software developed for smartphones. The increasing screen size on some smartphones has made them the equivalent of smaller computer tablets, leading some to call them phablets.  Introduction  Development of Computers  Digital Computers  Analog Computers  Bibliography 12) Explain in detail the application of IT in Library and Information work. APPLICATION OF INFORMATION TECHNOLOGY IN LIBRARY The library is the main information centre which can make use of the fat development IT for the benefits of mankind as a whole. The librarian’s preference of IT should include all those technologies which are expected to be used in the library activities/ operations and other library services for collection, processing, storage, retrieval and dissemination of recorded information, the fast
  • 9. Sundar B. N. Assistant Professor developing information technologies have showered almost every areas of application including libraries. In case of libraries, these are good use in the following environments. a) Library Management: Library management includes the following activities which will certainly be geared up by the use of these fast IT developments: Classification, Cataloguing, Indexing, Database creation, Database Indexing. b) Library Automation: Library automation is the concept of reducing the human intervention in all the library services so that any user can receive the desired information with the maximum comfort and at the lowest cot. Major areas of the automation can be classified into two -organization o f all library databases and all housekeeping operations of library. c) Library Networking: Library networking means a group pf Libraries and information Centres are interconnected for some common pattern or design for information exchange and communication with a view to improve efficiency. d) Audio-Video Technology: It includes photography, microfilms, microfiches, audio and tapes, printing, optical disk etc. e) Technical Communication: Technical Communication consisting of technical writing, editing, publishing, DTP systems etc CLASSIFICATION OF INFORMATION TECHNOLOGY BASED SERVICES Information technology based services can organize on the basis of three main criteria. I. Apparatus and Amenities II. Customer Services III. Electronic Sources I. Apparatus and Amenities: The equipments and facilities available in the library are illuminating in the following headings. a) Computers: Computer-based technologies have become dominant forces to shape and reshape the products and services the academic library has to offer. The success of the IT enabled services in the library is based on the efficiency of the equipment provided in the library i.e. most modern technology, not on the basis of number of equipments. b) OPAC: An Online Public Access Catalog (OPAC) is an online database of materials held by a library or group of libraries. Users search a library catalog principally to locate books and other material physically located at a library. c) Union Catalogue: A union catalog is a combined library catalog describing the collections of a number of libraries. Union catalogs have been created in a range of media, including book format, microform, cards and more recently, networked electronic databases. Union catalogs are useful to librarians, as they assist in locating and requesting materials from other libraries through interlibrary loan service .
  • 10. Sundar B. N. Assistant Professor d) CD-ROM: Presents a state-of-the-art review of the applications of CD-ROMs in academic libraries, embracing all aspects of library involvement and staffing implications. Concludes that CD- ROM is having a huge impact on the way academic libraries function and the services they offer to their users . e) Scanner: In computing, an image scanner—often abbreviated to just scanner— is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image.. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical. f) RFID: Radio frequency identification is a term used for technologies utilizing radio waves for identifying individual items automatically. The most common way is storing a serial number identifying a product and related information on a microchip attached to an antenna. RFID is used very similar to bar codes. g) Tele text: Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules. Teletext information is broadcast in the vertical blanking interval between image frames in a broadcast television signal . h) Facsimile: A facsimile is a copy or reproduction of an old book, manuscript, map, art, or other item of historical value that is as true to the original source as possible. It differs from other forms of reproduction by attempting to replicate the source as accurately as possible in terms of scale, color, condition, and other material qualities. For books and manuscripts, this also entails a complete copy of all pages; hence an incomplete copy is a "partial facsimile". i) Photocopy: A photocopier is a machine that makes paper copies of documents and other visual images quickly and cheaply. Most current photocopiers use a technology called xerography, a dry process using heat. Photocopying is widely used in library . II. Customer Services a) Document delivery services: The Document Delivery Service (DDS) delivers copies of journal articles and book chapters from participating Libraries. Fees apply for most Document Delivery Services. To fulfill the information needs of the end user through information/document supply is a document delivery service. This service is provided on No Profit - No Loss Basis and Expected to be prompt . b) Interlibrary loan: Inter library loan means a cooperative arrangement among libraries by which one library may borrow material from another library. In other words a loan of library materials by one library to another library. c) Indexing and abstracting services: a method which is used to retrieve information form a table in memory or a file on a direct access store or the art of compiling an index. The preparation of abstracts, usually in a limited field, by an individual, an industrial organization of r restricted use or a
  • 11. Sundar B. N. Assistant Professor commercial organization: the abstracts being published and supplied regularly to subscribers. Also the organization producing the abstracts. Such services may be either comprehensive or selective. d) Chat services: Online chat may refer to any kind of communication over the Internet, that offers an instantaneous transmission of text-based messages from sender to receiver, hence the delay for visual access to the sent message shall not hamper the flow of communications in any of the directions. Online chat may address as well point-to-point communications as well as multicast communications from one sender to many receivers . e) CAS: The purpose of a current-awareness service is to inform the users about new acquisitions in their libraries. Public libraries in particular have used display boards and shelves to draw attention to recent additions, and many libraries produce complete or selective lists for circulation to patrons. Some libraries have adopted a practice of selective dissemination of information. f) SDI: Selective dissemination of information ("SDI") was originally a phrase related to library and information science. SDI refers to tools and resources used to keep a user informed of new resources on specified topics. Selective Dissemination of Information (SDI) was a concept first described by Hans Peter Luhn of IBM in the 1950's. g) Scanned copies: A scanning service for material not available electronically, which is held by the Library. This includes articles from journals and chapters from books. Users of the service should be aware that we operate within the restrictions of the Copyright Act . h) Bulletin board services: A Bulletin Board System, or BBS, is a computer system running software that allows users to connect and log in to the system using a terminal. Once logged in, a user can perform functions such as uploading and downloading software and data, reading news and bulletins, and exchanging messages with other users, either through electronic mail or in public message boards. i) Electronic services and e- resources: The important fact is convincing many libraries to move towards digital e-resources, which are found to be less expensive and more useful for easy access. This is especially helpful to distant learners who have limited time to access the libraries from outside by internet access to commonly available electronic resources, mainly CD-ROM, OPACs, E-Journals, E-Books, ETD and Internet, which are replacing the print media. j) Digital library: A digital library is a library in which collections are stored in digital formats and accessible by computers. The digital content may be stored locally, or accessed remotely via computer networks. A digital library is a type of information retrieval system. III. Electronic Sources a) Audiovisual materials: The Audiovisual Collection contains a wide range of audiovisual material to support the research and study needs of staff and students . b) Internet: With the advent of digital revolution, communication has become easier and faster and decision are mad instantaneously. The internet which is the latest among the superhighways has cut
  • 12. Sundar B. N. Assistant Professor down the distance and made it easier to have access to information to all people at all places and at all the times. c) Library website: Library website helps to recognize the facilities and information sources available in the library. In most of the library website online catalogue is included. Online catalogue helps to ascertain a client whether the information is available in the library. d) Database: A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality, in a way that supports processes requiring the information. 13) What is application software? Explain the features of MS Excel. Application Software Application software products are designed to satisfy a particular need of a particular environment. All software applications prepared in the computer lab can come under the category of Application software. Application software may consist of a single program, such as Microsoft's notepad for writing and editing a simple text. It may also consist of a collection of programs, often called a software package, which work together to accomplish a task, such as a spreadsheet package. Examples of Application software are the following −  Payroll Software  Student Record Software  Inventory Management Software  Income Tax Software  Railways Reservation Software  Microsoft Office Suite Software  Microsoft Word  Microsoft Excel  Microsoft PowerPoint Features of application software are as follows −  Close to the user  Easy to design  More interactive  Slow in speed  Generally written in high-level language  Easy to understand  Easy to manipulate and use  Bigger in size and requires large storage space What is Excel? Microsoft Excel is a helpful and powerful program for data analysis and documentation. It is a spreadsheet program, which contains a number of columns and rows, where each intersection of
  • 13. Sundar B. N. Assistant Professor a column and a row is a “cell.” Each cell contains one point of data or one piece of information. By organizing the information in this way, you can make information easier to find, and automatically draw information from changing data. Features of Microsoft Excel 1. Add Header and Footer MS Excel allows us to keep the header and footer in our spreadsheet document. 2. Find and Replace Command MS Excel allows us to find the needed data (text and numbers) in the workbook and also replace the existing data with a new one. 3. Password Protection It allows the user to protect their workbooks by using a password from unauthorized access to their information. 4. Data Filtering Filtering is a quick and easy way to find and work with a subset of data in a range. A filtered range displays only the rows that meet the criteria you specify for a column. MS Excel provides two commands for filtering ranges: • AutoFilter; which includes filter by selection, for simple criteria • Advanced Filter; for more complex criteria 5. Data Sorting Data sorting is the process of arranging data in some logical order. MS Excel allows us to sort data either in ascending or descending order. 6. Built-in formulae MS Excel has got many built-in formulae for sum, average, minimum, etc. We can use those formulae as per our needs. 7. Create different charts (Pivot Table Report) MS Excel allows us to create different charts such as bar graph, pie- charts, line graphs, etc. This helps us to analyze and compare data very easily. 8. Automatically edits the result MS Excel automatically edits the result if any changes are made in any of the cells. 9. Formula Auditing Using formula auditing we can graphically display or trace the relationships between cells and formulas with blue arrows. We can trace the precedents (the cells that provide data to a specific cell) or the dependents (the cells that depend on the value in a specific cell). 14) Explain in detail the different devices used in the network. There are different types of electronic devices are used in networking which are known as network devices or network equipment. In a computer network, network devices are mainly used for transmitting and receiving the data quickly and securely in between computers, fax machines, printers, etc. These devices may be intra network or internetwork. There are some devices are installed on the device such as RJ45 connector otherwise NIC card, whereas some devices are part of the network namely switch, router, etc. These devices are specific devices, handles digital or electrical connections to perform their exclusive roles very efficiently. This article discusses an overview of network devices and their working.
  • 14. Sundar B. N. Assistant Professor What are Network Devices? Definition: The devices which are used for communication between different hardware’s used in the computer network are known as network devices. These devices are also known as physical devices, networking hardware, and network equipment otherwise computer networking devices. In a computer network, each network device plays a key role based on their functionality, and also works for different purposes at different segments. Types of Network Devices There are different types of network devices used in a computer network which include the following.  Network Hub  Network Switch  Modem  Network Router  Bridge  Repeater Network Hub The network hub is one kind of networking device in a computer network, used to communicate with various network hosts and also for data transferring. The transferring of data in a computer network can be done in the form of packets. Whenever the data processing can be done from a host to a network hub, then the data can transmit to all the connected ports. Similarly, all the ports identify the data path which leads to inefficiencies & wastage. Because of this working, a network hub cannot be so safe and secure. In addition, copying the data packets on all the ports will make the hub slower which leads to the utilize of the network switch. Network Switch Similar to a hub, this is also working at the layer in the LAN and a switch is more clever compare with a hub. As the hub is used for data transferring, whereas a switch is used for filtering & forwarding the data. So this is the more clever technique to deal with the data packets. Whenever a data packet is obtained from the interfaces in the switch, then the data packet can be filtered & transmits to the interface of the proposed receiver. Due to this reason, a switch maintains a content addressable memory table to maintain system configuration as well as memory. This table is also named as FIB (forwarding information base) otherwise forwarding table. Modem A modem is the most important network device and it is used daily in our life. If we notice the internet connection to homes was given with the help of a wire. then wire carries internet data from one place to another. But, every computer gives digital or binary data in the form of zeros & ones The full form of the modem is a modulator and a demodulator. So it modulates as well as demodulates the signal among the computer and a telephone line because the computer generates digital data whereas the telephone line generates an analog signal. Network Router A network router is one kind of network device in a computer network and it is used for routing traffic from one network to another. These two networks could be private to a public company network. For example, here a router is considered as traffic police at the junction, he directs dissimilar traffic networks to dissimilar directions. Bridge
  • 15. Sundar B. N. Assistant Professor A Bridge in the computer network is used to unite two or more network segments. The main function of a bridge in network architecture is to store as well as transmit frames among the various segments. Bridges use MAC (Media Access Control) hardware for transferring frames. These are also used for connecting two physical local area networks to a larger logical local area network. In the OSI model, bridges work at the data link & physical layers to divide the networks from larger to smaller by controlling the data flow between the two. In recent years, bridges are replaced by switches to provide more functionality. Repeater The operating of a repeater can be done at the physical layer. The main function of this device is to reproduce the signal on a similar network before the signal gets weak otherwise damaged. The significant point to be noted regarding these devices is that they do not strengthen the signal. Whenever the signal gets weak, then they reproduce it at the actual strength. A repeater is a two- port device. Gateway Generally, a gateway performs at the session & transport layers in the OSI model. Gateways offer conversion between networking technologies like OSI (Open System Interconnection) & TCP/IP. Because of this, these are connected to two or many autonomous networks, where each network has its own domain name service, routing algorithm, topology, protocols, and procedures of network administration & policies Gateways execute all the functions of routers. Actually, a router with additional conversion functionality is a gateway, so the conversion between various network technologies is known as a protocol converter. Brouter The Brouter is also called a bridging router and the main function of this is to combine the features of both router & bridge and router. It performs either at the network layer or the data link layer. When it works as a router, it is used for routing packets across networks whereas it works as a bridge; it is used for filtering LANs traffic. 15) Write an essay on Internet Services. What is Internet? The internet is the wider network that allows computer networks around the world run by companies, governments, universities and other organisations to talk to one another. The result is a mass of cables, computers, data centres, routers, servers, repeaters, satellites and wifi towers that allows digital information to travel around the world. It is that infrastructure that lets you order the weekly shop, share your life on Facebook, stream Outcast on Netflix, email your aunt in Wollongong and search the web for the world’s tiniest cat. In order to connect to the Internet, you need to use an Internet service. Internet service provides a way for data to be transferred from Internet servers to your computer. An Internet service provider is a company that provides access to the Internet. Most ISPs require you to subscribe in order to use their services, but there are ways to connect to the Internet for free. Some of the most common ways to connect to the Internet are dial-up, DSL, cable and wireless services. Internet Services allows us to access huge amount of information such as text, graphics, sound and software over the internet. Following diagram shows the four different categories of Internet Services.
  • 16. Sundar B. N. Assistant Professor a) Communication Services There are various Communication Services available that offer exchange of information with individuals or groups. The following table gives a brief introduction to these services: Electronic Mail Used to send electronic message over the internet Telnet Used to log on to a remote computer that is attached to internet Newsgroup Offers a forum for people to discuss topics of common interests. Internet Relay Chat (IRC) Allows the people from all over the world to communicate in real time Mailing Lists Used to organize group of internet users to share common information through e-mail Internet Telephony (VoIP) Allows the internet users to talk across internet to any PC equipped to receive the call Instant Messaging Offers real time chat between individuals and group of people. Eg. Yahoo messenger, MSN messenger. b) Information Retrieval Services There exist several Information retrieval services offering easy access to information present on the internet. The following table gives a brief introduction to these services: File Transfer Protocol (FTP) Enable the users to transfer files. Archie It’s updated database of public FTP sites and their content. It helps to search a file by its name Gopher Used to search, retrieve, and display documents on remote sites. Very Easy Rodent Oriented Netwide Index to Computer Achieved (VERONICA) VERONICA is gopher based resource. It allows access to the information resource stored on gopher’s servers. c) Web Services Web services allow exchange of information between applications on the web. Using web services, applications can easily interact with each other. The web services are offered using concept of Utility Computing. d) World Wide Web (WWW) WWW is also known as W3. It offers a way to access documents spread over the several servers over the internet. These documents may contain texts, graphics, audio, video, hyperlinks. The hyperlinks allow the users to navigate between the documents. Dial-up At one time, a dial-up account was the most common way to access the Internet. Accessing a dial- up connection requires you to use a landline telephone connection and a modem attached or connected to your computer. In order to establish the connection, you literally must instruct your computer to dial a telephone number provided by the ISP. A dial-up connection is the least
  • 17. Sundar B. N. Assistant Professor expensive and slowest way to connect to the Internet. Another disadvantage of dial-up is that you cannot make or receive phone calls while connected to the Internet. Some dial-up ISPs offer free, limited Internet access. DSL A digital subscriber line is another way to connect to the Internet through a telephone connection, but the quality and speed of the connection is significantly greater than a dial-up connection. And unlike a dial-up connection, DSL is "always on," which means you can still make and receive telephone calls with your land line telephone. One thing to consider is that DSL Internet services are not available in all areas. Cable A cable Internet connection is established by subscribing to an account with a local cable television provider and connecting a cable modem to your computer. Cable Internet connections are capable of transmitting data faster than a DSL connection. Like DSL, a cable Internet connection is always on and does not interfere with your telephone access. The cost of a subscription with a cable ISP can be equal to or greater than a DSL subscription. Wireless A wireless Internet connection does not require your desktop or notebook computer to be connected to telephone or cable wires. You simply need a modem and an account with a wireless Internet provider. In many areas, you can access a wireless connection free of charge. Many coffee shops, restaurants, public libraries and schools offer free wireless Internet connection. Video Conferencing Video conferencing or Video teleconferencing is a method of communicating by two-way video and audio transmission with help of telecommunication technologies. 16) Hard Disk. Hard Disk Drive - Hard disk drive is made up of a series of circular disks called platters arranged one over the other almost ½ inches apart around a spindle. Disks are made of non-magnetic material like aluminum alloy and coated with 10-20 nm of magnetic material. Standard diameter of these disks is 14 inches and they rotate with speeds varying from 4200 rpm (rotations per minute) for personal computers to 15000 rpm for servers. Data is stored by magnetizing or demagnetizing the magnetic coating. A magnetic reader arm is used to read data from and write data to the disks. A typical modern HDD has capacity in terabytes (TB). A hard drive fits inside a computer case and is firmly attached with the use of braces and screws to prevent it from being jarred as it spins. Typically it spins at 5,400 to 15,000 RPM. The disk moves at an accelerated rate, allowing data to be accessed immediately. Most hard drives operate on high speed interfaces using serial ATA (SATA) or serial attached technology. When the platters rotate, an arm with a read/write head extends across the platters. The arm writes new data to the platters and reads new data from them. Most hard drives use enhanced integrated drive electronics (EIDE) including cables and connectors to the motherboard. All data is stored magnetically, allowing information to be saved when power is shut off. Hard drives need a read only memory (ROM) controller board to instruct the read/write heads how, when and where to move across the platters. Hard drives have disks stacked together and
  • 18. Sundar B. N. Assistant Professor spin in unison. The read/write heads are controlled by an actuator, which magnetically reads from and writes to the platters. The read/write heads float on a film of air above the platters. Both sides of the platters are used to store data. Each side or surface of one disk is called a head, with each one divided into sectors and tracks. All tracks are the same distance from the center of the disk. Collectively they comprise one cylinder. Data is written to a disk starting at the furthest track. The read/write heads move inward to the next cylinder once the first cylinder is filled. A hard drive is divided into one of more partitions, which can be further divided into logical drives or volumes. Usually a master boot record (MBR) is found at the beginning of the hard drive and contains a table of partition information. Each logical drive contains a boot record, a file allocation table (FAT) and a root directory for the FAT file system 17) Flow Chart. What is a Flowchart? Flowchart is a graphical representation of an algorithm. Programmers often use it as a program- planning tool to solve a problem. It makes use of symbols which are connected among them to indicate the flow of information and processing. The process of drawing a flowchart for an algorithm is known as “flowcharting”. 1. Terminal: The oval symbol indicates Start, Stop and Halt in a program’s logic flow. A pause/halt is generally used in a program logic under some error conditions. Terminal is the first and last symbols in the flowchart. 2. Input/Output: A parallelogram denotes any function of input/output type. Program instructions that take input from input devices and display output on output devices are indicated with parallelogram in a flowchart. 3. Processing: A box represents arithmetic instructions. All arithmetic processes such as adding, subtracting, multiplication and division are indicated by action or process symbol. 4. Decision Diamond symbol represents a decision point. Decision based operations such as yes/no question or true/false are indicated by diamond in flowchart. 5. Connectors: Whenever flowchart becomes complex or it spreads over more than one page, it is useful to use connectors to avoid any confusions. It is represented by a circle. 6. Flow lines: Flow lines indicate the exact sequence in which instructions are executed. Arrows represent the direction of flow of control and relationship among different symbols of flowchart. 7. 18) Indexed sequential access file organization  Indexed sequential access file combines both sequential file and direct access file organization.  In indexed sequential access file, records are stored randomly on a direct access device such as magnetic disk by a primary key.
  • 19. Sundar B. N. Assistant Professor  This file have multiple keys. These keys can be alphanumeric in which the records are ordered is called primary key.  The data can be access either sequentially or randomly using the index. The index is stored in a file and read into memory when the file is opened. Advantages of Indexed sequential access file organization  In indexed sequential access file, sequential file and random file access is possible.  It accesses the records very fast if the index table is properly organized.  The records can be inserted in the middle of the file.  It provides quick access for sequential and direct processing.  It reduces the degree of the sequential search. Disadvantages of Indexed sequential access file organization  Indexed sequential access file requires unique keys and periodic reorganization.  Indexed sequential access file takes longer time to search the index for the data access or retrieval.  It requires more storage space.  It is expensive because it requires special software.  It is less efficient in the use of storage space as compared to other file organizations. 19) Transmission Modes. Transmission mode refers to the mechanism of transferring of data between two devices connected over a network. It is also called Communication Mode. These modes direct the direction of flow of information. There are three types of transmission modes. They are:  Simplex Mode  Half duplex Mode  Full duplex Mode SIMPLEX Mode In this type of transmission mode, data can be sent only in one direction i.e. communication is unidirectional. We cannot send a message back to the sender. Unidirectional communication is done in Simplex Systems where we just need to send a command/signal, and do not expect any response back. Examples of simplex Mode are loudspeakers, television broadcasting, television and remote, keyboard and monitor etc.
  • 20. Sundar B. N. Assistant Professor HALF DUPLEX Mode Half-duplex data transmission means that data can be transmitted in both directions on a signal carrier, but not at the same time. For example, on a local area network using a technology that has half-duplex transmission, one workstation can send data on the line and then immediately receive data on the line from the same direction in which data was just transmitted. Hence half-duplex transmission implies a bidirectional line (one that can carry data in both directions) but data can be sent in only one direction at a time. Example of half duplex is a walkie- talkie in which message is sent one at a time but messages are sent in both the directions. FULL DUPLEX Mode In full duplex system we can send data in both the directions as it is bidirectional at the same time in other words, data can be sent in both directions simultaneously. Example of Full Duplex is a Telephone Network in which there is communication between two persons by a telephone line, using which both can talk and listen at the same time. In full duplex system there can be two lines one for sending the data and the other for receiving data. 20) TCP/IP. The Internet Protocol (IP) is the address system of the Internet and has the core function of delivering packets of information from a source device to a target device. IP is the primary way in which network connections are made, and it establishes the basis of the Internet. IP does not handle packet ordering or error checking. Such functionality requires another protocol, typically TCP.The TCP/IP relationship is similar to sending someone a message written on a puzzle through the mail. The message is written down and the puzzle is broken into pieces. Each piece then can travel through a different postal route, some of which take longer than others. When the puzzle pieces arrive after traversing their different paths, the pieces may be out of order. The Internet Protocol makes sure the pieces arrive at their destination address. The TCP protocol can be thought of as the puzzle assembler on the other side who puts the pieces together in the right order, asks for missing pieces to be resent, and lets the sender know the puzzle has been received. TCP maintains the connection with the sender from before the first puzzle piece is sent to after the final piece is sent.IP is a connectionless protocol, which means that each unit of data is individually addressed and routed from the source device to the target device, and the target does not send an acknowledgement back to the source. That’s where protocols such as the Transmission Control Protocol (TCP) come in. TCP is used in conjunction with IP in order to maintain a connection between the sender and the target and to ensure packet order. For example, when an email is sent over TCP, a connection is established and a 3-way handshake is made. First, the source send an SYN “initial request” packet to the target server in order to start the dialogue. Then the target server then sends a SYN-ACK packet to agree to the process. Lastly, the source sends an ACK packet to the target to confirm the process, after which the message contents can be sent. The email message is ultimately broken down into packets before each packet is sent out into the Internet, where it traverses a series of gateways before arriving at the target device where the group of packets are reassembled by TCP into the original contents of the email.