UGC NET- INFORMATION AND COMMUNICATION (Computer) STUDY MATERIAL

Margus UGC NET- INFORMATION AND COMMUNICATION (Computer) STUDY MATERIAL

Computer is an advanced electronic device that takes raw data as an input from the user and processes it under the control of a set of instructions (called program), produces a result (output), and saves it for future use. This tutorial explains the foundational concepts of computer hardware, software, operating systems, peripherals, etc. along with how to get the most value and impact from computer technology.

Functionalities of a Computer

If we look at it in a very broad sense, any digital computer carries out the following five functions −

Step 1 − Takes data as input.

Step 2 − Stores the data/instructions in its memory and uses them as required.

Step 3 − Processes the data and converts it into useful information.

Step 4 − Generates the output.

Step 5 − Controls all the above four steps.

Advantages of Computers

Following are certain advantages of computers.

High Speed

·        Computer is a very fast device.

·        It is capable of performing calculation of very large amount of data.

·        The computer has units of speed in microsecond, nanosecond, and even the picosecond.

·        It can perform millions of calculations in a few seconds as compared to man who will spend many months to perform the same task.

There are five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics.

S.No	Generation & Description
1	First Generation The period of first generation: 1946-1959. Vacuum tube based.
2	Second Generation The period of second generation: 1959-1965. Transistor based.
3	Third Generation The period of third generation: 1965-1971. Integrated Circuit based.
4	Fourth Generation The period of fourth generation: 1971-1980. VLSI microprocessor based.
5	Fifth Generation The period of fifth generation: 1980-onwards. ULSI microprocessor based.

Types of Computer On the basis of working principle

a)    Analog Computer: An analog computer (spelt analogue in British English) is a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved.

b)    Digital Computer: A computer that performs calculations and logical operations with quantities rep- resented as digits, usually in the binary number system.

c)    Hybrid Computer (Analog + Digital): A combination of computers those are capable of inputting and outputting in both digital and analog signals. A hybrid computer system setup offers a cost-effective method of performing complex simulations.

PC (Personal Computer)

A PC can be defined as a small, relatively inexpensive computer designed for an individual user. PCs are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip.

Workstation

Workstation is a computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other such types of applications which require a moderate amount of computing power and relatively high-quality graphics capabilities.

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users simultaneously.

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting hundreds or even thousands of users simultaneously. Mainframe executes many programs concurrently and supports many simultaneous execution of programs.

Supercomputer

Supercomputers are one of the fastest computers currently available. Supercomputers are very expensive and are employed for specialized applications that require immense amount of mathematical calculations (number crunching).

For example, weather forecasting, scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data (e.g. in petrochemical prospecting).

Input Devices

Following are some of the important input devices which are used in a computer −

• Keyboard
• Mouse
• Joy Stick
• Light pen
• Track Ball
• Scanner
• Graphic Tablet
• Microphone
• Magnetic Ink Card Reader(MICR)
• Optical Character Reader(OCR)
• Bar Code Reader
• Optical Mark Reader(OMR)

Output Devices

Following are some of the important output devices used in a computer.

• Monitors
• Graphic Plotter
• Printer

What is Memory?

A memory is just like a human brain. It is used to store data and instructions. Computer memory is the storage space in the computer, where data is to be processed and instructions required for processing are stored. The memory is divided into large number of small parts called cells. Each location or cell has a unique address, which varies from zero to memory size minus one. For example, if the computer has 64k words, then this memory unit has 64 * 1024 = 65536 memory locations. The address of these locations varies from 0 to 65535.

Memory is primarily of three types −

• Cache Memory
• Primary Memory/Main Memory
• Secondary Memory

Data Measure

The following table lists some higher storage units −

S.No.	Unit & Description
1	Kilobyte (KB) 1 KB = 1024 Bytes
2	Megabyte (MB) 1 MB = 1024 KB
3	GigaByte (GB) 1 GB = 1024 MB
4	TeraByte (TB) 1 TB = 1024 GB
5	PetaByte (PB) 1 PB = 1024 TB

Computer - Some Important Abbreviations

A

·                     Al – Artificial intelligence

·                     ALGOL – Algorithmic Language

·                     ARP – Address resolution Protocol

·                     ASCII – American Standard Code for Information Interchange
B

·                     BINAC  - Binary Automatic Computer

·                     BCC – Blind Carbon Copy

·                     Bin – Binary

·                     BASIC - Beginner’s All-purpose Symbolic Instruction Code

·                     BIOS – Basic Input Output System

·                     Bit – Binary Digit

·                     BSNL – Bharat Sanchar Nigam Limited
C

·                     CC – Carbon Copy

·                     CAD – Computer Aided Design

·                     COBOL – Common Business Oriented Language

·                     CD – Compact Disc

·                     CRT – Cathode Ray Tube 

·                     CDR – Compact Disc Recordable

·                     CDROM – Compact Disc Read Only Memory 

·                     CDRW – Compact Disc Rewritable

·                     CDR/W – Compact Disk Read/Write
D

·                     DBA – Data Base Administrator

·                     DBMS – Data Base Management System 

·                     DNS – Domain Name System

·                     DPI – Dots Per Inch

·                     DRAM – Dynamic Random Access Memory

·                     DVD – Digital Video Disc/Digital Versatile Disc

·                     DVDR – DVD Recordable

·                     DVDROM – DVD Read Only Memory

·                     DVDRW – DVD Rewritable

·                     DVR – Digital Video Recorder

·                     DOS – Disk Operating System
E

·                     EBCDIC – Extended Binary Coded Decimal Interchange Code

·                     e-Commerce – Electronic Commerce

·                     EDP – Electronic Data Processing

·                     EEPROM – Electrically Erasable Programmable Read Only Memory

·                     ELM/e-Mail – Electronic Mail

·                     ENIAC - Electronic Numerical Integrator and Computer 

·                     EOF - End Of File 

·                     EPROM - Erasable Programmable Read Only Memory 

·                     EXE - Executable 

F

·                     FAX - Far Away Xerox/ facsimile

·                     FDC - Floppy Disk Controller 

·                     FDD - Floppy Disk Drive 

·                     FORTRAN - Formula Translation 

·                     FS - File System 

·                     FTP - File Transfer Protocol
G

·                     Gb - Gigabit 

·                     GB - Gigabyte 

·                     GIF - Graphics Interchange Format 

·                     GSM -  Global System for Mobile Communication

H

·                     HDD - Hard Disk Drive 

·                     HP - Hewlett Packard

·                     HTML - Hyper Text Markup Language 

·                     HTTP - Hyper Text Transfer Protocol
I

·                     IBM - International Business Machine 

·                     IM - Instant Message

·                     IMAP - Internet Message Access Protocol 

·                     ISP - Internet Service Provider
J

·                     JPEG - Joint Photographic Experts Group
K

·                     Kb - Kilobit 

·                     KB - Kilobyte 

·                     KHz - Kilohertz 

·                     Kbps - Kilobit Per Second
L

·                     LCD – Liquid Crystal Display

·                     LED – Light Emitting Diode

·                     LPI – Lines Per Inch

·                     LIS – Large Scale Integration
M

·                     Mb – Megabit

·                     MB – Megabyte

·                     MPEG – Moving Picture Experts Group

·                     MMS – Multimedia Message Service

·                     MICR – Magnetic Ink Character reader

·                     MIPS – Million Instructions Per Second
N

·                     NIC – Network Interface Card

·                     NOS – Network Operating System
O

·                     OMR – Optical Mark Reader

·                     OOP – Object Oriented Programming

·                     OSS – Open Source Software
P

·                     PAN – Personal Area Network

·                     PC – Personal Computer

·                     PDA - Personal Digital Assistant

·                     PDF – Portable Document Format

·                     POS – Point Of Sale

·                     PNG - Portable Network Graphics

·                     PPM – Pages Per Minute

·                     PPP – Point-to-Point Protocol

·                     PROM – Programmable Read Only Memory

·                     PSTN – Public Switched Telephone Network

·                     POST – Power OnSelf Test

·                     PING – Packet Internet Gopher
R

·                     RAM – Random Access Memory

·                     RDBMS – Relational Data Base Management System

·                     RIP – Routing Information Protocol

·                     RTF – Rich Text Format
S

·                     SMTP – Simple Mail Transfer Protocol

·                     SQL – Structured Query Language

·                     SRAM – Static Random Access Memory

·                     SNMP – Simple Network Management Protocol

·                     SIM – Subscriber Identification Module
T

·                     TCP – Transmission Control Protocol

·                     TB – Tera Bytes
U

·                     UPS – Uninterrupted Power Supply

·                     URI – Uniform Resource Identifier

·                     URL – Uniform Resource Locator

·                     USB -  Universal Serial Bus 

·                     ULSI - Ultra Large Scale Integration

·                     UNIVAC - Universal Automatic Computer
V

·                     VAR – Variable

·                     VGA – Video Graphics Array

·                     VSNL – Videsh Sanchar Nigam Limited

·                     VDU – Visual Display Unit
W

·                     Wi-Fi – Wireless Fidelity

·                     WLAN – Wireless Local Area Network

·                     WPA – Wi-Fi Protected Access

·                     WWW – World Wide Web

·                     WORM – Write Once Read Many
X

·                     XHTML – eXtensibleHyper text Markup Language

·                     XML -  eXtensible Markup language
Z

·                     ZB – Zeta Byte

 

General definition andterminology

∙   Monitor: A device used to display informationvisually

∙   Mouse: A peripheral device used to point to items on a monitor

∙  

∙

NIC: Network interface card; a board inserted in a computer that provides a physical connection to a network

∙   Printer: A peripheral device that converts output from a computer into a printedimage

∙

Applications: Complete, self-contained programs that perform a specific function (ie. spread- sheets, databases)

Bit: A computer’s most basic unit of information

∙

Boot: The process of loading or initializing an operating system on a computer; usually occursas soon as a computer is turnedon

∙

Browser:AprogramusedtoviewWorldWideWebpages,suchasNetscapeNavigatororInternet Explorer

∙

Bug: A part of a program that usually causes the computer to malfunction; often remedied in patches or updates to the program

∙   Byte: Small unit of data storage; 8 bits; usually holds one character

∙

Click: Occurs when a user presses a button on a mouse which in turn, generates a command to the computer

∙

Database: A large structured set of data; a file that contains numerous records that contain nu- merous fields

∙   Diskette: A small flexible disk used for storing computer data

∙

Double Click: Occurs when a user presses a button on the mouse twice in quick succession; this generates a command to the computer

∙   Download: Transferring data from another computer to yourcomputer

∙

Drag: Occurs when a user points the mouse at an icon or folder, presses the button and without releasing the button, moves the icon or folder to another place on the computer where the button is released

∙   Driver: Software program that controls a piece of hardware or aperipheral

∙

FAQ:Frequentlyaskedquestion;documentsthatanswerquestionscommontoaparticularwebsite orprogram

∙   File: Namable unit of data storage; an element of data storage; a single sequence ofbytes

∙

Folder: A graphical representation used to organize a collection of computer files; as in the con- cept of a filing cabinet (computer’s hard drive) with files (folders)

∙   Freeware: Software provided at no cost to theuser

∙   Gigabyte: 1,073,741,824 bytes or 1,024 megabytes; generally abbreviated GB

∙   GUI: Graphical user interface; uses pictures and words to represent ideas, choices, functions,etc.

∙   Icon: A small picture used to represent a file or program in a GUIinterface

∙

Internet: A network of computer networks encompassing the World Wide Web, FTP, telnet, and many other protocols

∙   IP number: Internet protocol; a computer’s unique address or number on theInternet

∙   Kilobyte: 1,024 bytes; usually abbreviatedKB

∙

Megabyte:1,048,576bytesor1,024kilobytes;enoughstoragetoapproximatelyequala600-page paperback book; generally abbreviatedMb

∙   Memory: Any device that holds computerdata

∙   Menu: A list of operations available to the user of a program

∙   etwork: A collection of computers that areconnected

∙   Peripheral: Any of a number of hardware devices connected to aCPU

∙

RAM:Randomaccessmemory;thetypeofstoragethatchanges;whenthecomputeristurnedoff, the RAM memory iserased

∙

ROM: Read-only memory; the type of storage that is not changed even when the computer is turned off

∙

Scroll Bar: Allows the user to control which portion of the document is visible in the window; available either horizontally or vertically or both

∙

Shareware: Software provided at a minimal cost to users who are on their honor to send in payment to the programmer

∙ Spreadsheet: A program arranged in rows and columns that manipulates numbers

∙

Tool Bar: A graphical representation of program activities; a row of icons used to perform tasks in a program

∙

URL: Uniform resource locator; the address of a site on the World Wide Web; a standard way of locating objects on the Internet

∙

Virus: A deliberately harmful computer program designed to create annoying glitches or destroy data

∙

Window: A screen in a software program that permits the user to view several programs at one time

∙   Word Processor: A program that allows the user to create primarily textdocument.

∙

CPU: Central processing unit; the brain of the computer; controls the other elements of the computer

∙   Disk Drive: A peripheral device that reads and/or writes information on adisk

∙

Hard Drive: A device (usually within the computer case) that reads and writes information, including the operating system, program files, and data files

∙   Keyboard: A peripheral used to input data by pressingkeys

∙   Modem: A peripheral device used to connect one computer to another over a phoneline

391

∙

ApplicationFiles: Programfilesenvironmentwhereyoucancreateandeditthekindofdocument that applicationmakes.

∙

Click: Toselectanobjectbypressingthemousebuttonwhenthecursorispointingtotherequired menu option, icon or hypertextlink.

∙ Close: To close a window that has been opened for viewing and / or editing.

∙

Computer: A general-purpose machine that processes data according to a set of instructions that are stored internally either temporarily or permanently.

∙

CentralProcessorUnit(CPU): CentralProcessorUnit–themainchiponthecomputerthatmakes everythinggo.

∙

Crash: Your computer or application no longer works correctly and so you” loose” all the work you’ve done since the last time you saved.

∙

CreatingAFile: Storingdataasafilewithanassignedfilenamethatisuniquewithinthedirectory it residesin.

∙   Delete: Toremove an item of data from a file or to remove a file from thedisk.

∙

Desktop: An on-screen representation of a desktop such as used in the Macintosh and Windows operating systems.

∙   Dialog Boxes: Takesover your screen and allows you to” dialog” with thecomputer.

∙   Directory (AKA Folder, sub-directory): Allows you to organize files and otherfolders.

∙

Disk Space: This is the place where your files live. The greater the disk space the more files you can keep. (See also Megabytes) More disk space is always better than less. You can never have much disk space.

∙   Documents: Files you create andedit.

∙   Document Files: Files we care about (memos, letters, pictures,etc.)

∙

Double Click: To press the mouse button twice in rapid succession without moving the mouse between clicks.

∙

Drag: Tomove an object on screen in which its complete movement is visible from startinglocation todestination.

∙   Edit: Tomake a change to existingdata.

∙

File Cabinet: Metaphorically, the hard drive (and other kinds of storage media like floppydisks) which store files andfolders.

∙   Folder (AKA Directory, Sub-Directory): Allows you to organize files and otherfolders.

∙   Folder Icons: Collections of documents and otherfolders.

∙

Icons:

Inagraphicaluserinterface(GUI),asmall,pictorial,onscreenrepresentationofanobject, such as a document, program, folder or diskdrive.

∙   Icon View: Allows you to see icons of folders and files primarily as icons with littleinformation.

∙

Keyboard: This if the primary text input device. It also contains certain standard function keys, suchastheEscapekey,tab,andarrowkeys,shiftandcontrolkeys,andsometimesothermanufacturer- customizedkeys.

∙   Kilo (K): This is a unit of measure = 1,000. So, 1,000 bytes is aKiloByte.

∙

List View: Shows the icons but also orders the icons (often by name, but can sort the list in other ways) and shows more information about them.

∙

Macintosh: The brand name of a family of personal computers (hardware) and an operating sys- tem (software) from Apple, introduced in 1984.

∙

Megabytes (Mb): Mega = million so Mb is 1,000,000 bytes. It’s enough information for the computer to store one character (e.g.” h”), so 1mb text file = 1,000,000 keystrokes in that file. Just to confound the masses, although RAM and Disk Space do something completely different we measure both in megabytes. This leads to confusion.

∙   Menu: Displays a list of commands, some with images next tothem.

∙   Modifier Keys: Keysthat change the meaning of what youtype.

∙   Mouse: Pointing device that allows you to tell the computer what todo.

∙   Operating System (OS): System software that allows your computer towork.

∙

Pointer (AKA Cursor): The name of the arrow (or other shape) that tracks across the screen as you move the mouse (or another pointing device) around.

∙

Random Access Memory (RAM): This stands for Random Access Memory. You can think of this as the” space” where your computer does its processing. The more space you have the more processesyoucanrunatthesametime.MoreRAMisalwaysbetterthanless.You canneverhave muchRAM.

∙

RecycleBin: Placewhereyouputfilesandfoldersthatyoumaylaterwanttodeleteorgetridof. CompareTrash.

∙   Resize Box: Allows you to change the size and shape of awindow.

∙

Rightclick: Topresstherightbuttononthemouse.(ThisisWindowsspecific.OnaMacrunning System 8 or higher, you hold down the Control key and then click to get the sameeffect.)

∙

Save: Tellthe computer to create a file on disk that has the information you’ve put into the docu- ment (usually typing).

∙   Save As: Givethe file a name and/or store the file in a certainplace.

∙   Scroll bar: Allows you to move around through yourdocument.

∙   Shut down: Toquit all applications and turn off thecomputer.

∙   Software: Instructions that tell the computer what todo.

∙   System files: Allows our computer towork.

∙   Trash: Place where you put files and folders that you want to delete or get ridof.

∙   Volume Icons: Devices that hold files andfolders.

∙

Windows :1) The most widely used operating system for personal computers from Microsoft. (Software only.Other companies manufacture the hardware that runs the Windows Operating System.) Compare Macintosh. (Windows with a large” W”.)

∙   Hardware port: any place on the computer where devices can be pluggedin

∙   USB: type of computer port used for keyboards, drives, mouse,etc.

∙   CD drive: a piece of hardware that readsCD’s

∙   Hardware: physical parts of the computer and devices used with acomputer

∙   Software: computerprograms

∙

Operatingsystem: softwarethatcommunicatedwithhardwareenablingothersoftwaretorun(example: Windows, Mac OS, andLinux)

∙   Icon: A visual representation of files and programs on thecomputer

∙   Shortcut: uses an icon like a button to go directly to a file orprogram

∙   Folder: store files just like realfolders

∙

File: acollectionofdatastoredinoneunit,identifiedbyafilename (examples:document,pictures, videos,etc.)

∙   Window: an area on the screen that displays information for a specificprogram

∙   Dialog box: a window that pops up with options for the user toselect

∙   Toolbar: a set of icons or buttons that is part of the software beingused393

Important Computer Extensions

The topic is File Name Extensions.

Text Files

.log: Log File

.wpd: WordPerfect Document

.odt:  OpenDocument

.pages:  Pages Document

.doc:  Microsoft Word Document

.docx:  Microsoft Word Open XML Document

.tex:  LaTeX Source Document

.wps:  Microsoft Works Word Processor Document

.msg:  Outlook Mail Message

.rtfRich:  Text Format File

.txtPlain:  Text File

Data Files

.vcf:  vCard File

.dat:  Data File

.pptx:  PowerPoint Open XML Presentation

.sdf:  Standard Data File

.tar:  Consolidated Unix File Archive

.csv:  Comma Seperated Values File

.xml:  XML File

.pps:  PowerPoint Slide Show

.ppt:  PowerPoint Presentation

Audio Files

.aif:  Audio Interchange File Format

.mpa:  MPEG-2 Audio File

.ra:  Real Audio File

.iff:  Interchange File Format

.wav:  WAVE Audio File

.wma:  Windows Media Audio File

.mp3:  MP3 Audio File

Video Files

.avi:  Audio Video Interleave File

.3gp3:  GPP Multimedia File

.flv:  Flash Video File

.mpg:  MPEG Video File

.vob:  DVD Video Object File

.mp4:  MPEG-4 Video File

.3g:  23GPP2 Multimedia File

.m4:  viTunes
.wmv:  Windows Media Video File

Computer Networking

Computer Networking: A computer network is a set of connected computers. Computers on a network are called nodes. The connection between computers can be done via cabling, most commonly the Ethernet cable, or wirelessly through radio waves. Connected computers can share resources, like access to the Internet, printers, file servers, and others.

Components:

1.Server – a computer designed to process requests and deliver data to other (client) computers over a local network or the Internet.

2.Receiver – a hardware module or device used to receive signals

3.Channel – physical connection between Server & Receiver

Transmission Channel:

Simplex channels – simplex is a communications channel that operates in one direction at a time.

Half duplex channel – A half-duplex channel can send and receive data, but not at the same time.

Full duplex channel – Refers to the transmission of data in two directions simultaneously.

Types Data communication medium

 Standard Telephone Line                                                Co-Axial Cable

 Microwave Transmission                                                   Satellite Communication

 Optical Fibers

Network devices

• Network adapter is a device that enables a computer to connect with other computer/network using MAC Address
• Hub is a device that splits a network connection into multiple computers
• Switch is a telecommunication device grouped as one of computer network components
• Cable is one way of transmission media which can transmit communication signals.
• Repeaters is used to regenerate or replicate signals that are weakened or distorted by transmission over long distances
• Bridge is used two connect two LANs with the same standard but using different types of cables
• Routers is used to join multiple computer networks together via either wired or wireless connections.

• Gateways is a key stopping point for data on its way to or from other networks.

• MODEM – Modulator-demodulator. Electronic device that allows computers to communicate over telephone wires or cable-TV cable.

Types of Network

• Local Area Network(LAN) – a computer network that links devices within a building or group of adjacent Ex – Star LAN, Ring LAN, Bus LAN
• Wide Area Network(WAN) – a computer network in which the computers connected may be far apart.
• Metropolitan Area Network (MAN)- A metropolitan area network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a LAN but smaller than the area covered by WAN. Ex- Public Networks Public Switched Telephone Networks (PSTN) Public Service Digital Network (PSDN)
• Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data

Data transmission

• NIC-Network interface card – A network interface card (NIC) is a computer circuit board or card that is installed in a computer so that it can be connected to a network.
• Wireless technology – Wireless communications is a type of data, a wireless signal through wireless communication technologies and device.

Network Related Terms

• Protocol – It is set of rules and standards which is used by computers to exchange data or information with each other across a network.
• Nodes – It is a connect point where either data transmission ends or redistribution of data starts.
• TCP/IP (Transmission Control Protocol/Internet Protocol) – basic communication language or protocol of the Internet.

          IPV4 – 32 bits numeric address

IPV6 – 128 bits hexadecimal address

• File Transfer Protocol (FTP) is a standard network protocol used to transfer computer files between a client and server on a computer network.
• Internet service provider (ISP) is an organization that provides services for accessing and using the Internet.
• Network Service Provider (NSP) is a company that provides backbone services to an Internet service provider (ISP).
• Web server is a program that uses HTTP (Hypertext Transfer Protocol) to serve the files that form Web pages to users, in response to their requests, which are forwarded by their computers’ HTTP clients.
• Website is a collection of related web pages, including multimedia content, typically identified with a common domain name
• Web Page is a hypertext document connected to the World Wide Web.
• Home page – the introductory page of a website
• Hyperlink is a word, phrase, or image that you can click on to jump to a new document or a new section within the current document.
• Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems.
• Wireless Application Protocol (WAP) is a technical standard for accessing information over a mobile wireless network.
• URL (Uniform Resource Locator) is a form of URI and is a standardized naming convention for addressing documents accessible over the Internet and Intranet.

Internet

• Internet- a global computer network providing a variety of information and communication facilities, consisting of interconnected networks using standardized communication protocols.
• Modem – a combined device for modulation and demodulation, for example, between the digital data of a computer and the analogue signal of a telephone line.
• Web Browser – Web browser is a software application used to locate, retrieve and display content on the World Wide Web, including Web pages, images and video.