Introduction to Computers

Introduction toIntroduction to Computers Computers

04/21/2304/21/23 Introduction to ComputersIntroduction to Computers 22

A Desktop MachineA Desktop Machine

A Computer SystemA Computer System

• Hardware• Software• User

Hardware

Software

A Computer System A Computer System (Contd.)(Contd.)

• In general, a computer is a machine which accepts data, processes it and returns new information as output.

Data Information

Processing

SoftwareSoftware• Software is set of programs (which are step by

step instructions) telling the computer how to process data.

• Software needs to be installed on a computer, usually from a CD.

• Softwares can be divided into two groups: - System SW - Application SW

Software Software (Contd.)(Contd.)

System Software• It controls the overall operation of the system.

• It is stored in the computer's memory and instructs the computer to load, store, and execute an application.

• Examples: Operating System (OS), Translators

DOS, Windows, Unix etc.

Software Software (Contd..)(Contd..)Application Software• They are Softwares written to perform specific

tasks.

• The basic types of application software are:

word processing, database, spreadsheet, desktop publishing, and communication.

Examples: MSOffice, Tally, MSOutlook,

ISBS, MODBANKER BANKSOFT

Advantages of Using Advantages of Using ComputersComputers

• Speed: Computers can carry out instructions in less than a millionth of a second.

• Accuracy : Computers can do the calculations without errors and very accurately.

• Diligence : Computers are capable of performing any task given to them repetitively.

• Storage Capacity : Computers can store large volume of data and information on magnetic media.

History of Evolution Of History of Evolution Of ComputersComputers

Two Eras:• Mechanical Era (Before 1945)• Electronic Era (1945 - )

Can be divided into generations.• First Generation (1945 – 1954)• Second Generation (1955 – 1964)• Third Generation (1965 – 1974)• Fourth Generation (1975 - )

Types of Types of ComputersComputersOn the basis of Computing Power & Size:• Laptop / Palmtop • Micro Computer / Desktop• Mini Computer / Mainframe• Super Computer

Language of Language of ComputersComputers• Computers only understand the electronic

signals.

Either Current is flowing or not.• Current Flowing : ON• Current Not Flowing : OFF

• Binary Language • ON : 1• OFF : 0

• Bit, Byte, KB, MB, GB

Computer NetworkComputer Network

• A Computer Network is interconnection of Computers to share resources.

• Resources can be : Information, Load, Devices etc.

Types Of Computer Types Of Computer NetworksNetworks

On the basis of Size:• Local Area Network (LAN)

Its a network of the computers locally i.e. in

one room, one building. • Wide Area Network (WAN)

Its a network of the computers spread widely

geographically.

Benefits of Computer Benefits of Computer NetworksNetworks

• Information Sharing• Device Sharing• Load Sharing• Mobility• Fast Communication• Anywhere Anytime Banking

InternetInternet

• Internet is a huge network of computer networks.

• Internet provides many services:

– Email– World Wide Web (www)– Remote Login (Telnet)– File Transfer (FTP)

End Of Session #1

ANY Queries ??????

CPU ( Central Processing CPU ( Central Processing Unit)Unit)

• The central processing unit (CPU), also known as just a "processor”, is the "brain" of your computer.

• It contains various electronic circuits.

VDU (Monitor)VDU (Monitor)

• This is the television-like screen where the results of a computer's tasks are displayed.

• Monitors come in all sizes, but most commonly they are either 15 or 17 inches

(measured diagonally from one corner of the screen to the opposite corner).

KeyboardKeyboard

• The keyboard looks like a typewriter.

• It contains all the letters of the alphabet, numbers and some special symbols.

• It operates like a typewriter keypad, but instead of moving an arm, which strikes the paper, it sends an electronic impulse to the computer, which displays a character on the monitor.

• Its a device that is used to control the computer. A cable connects the mouse to the computer.

• When the mouse is moved on a pad, called a mouse pad, the cursor on the screen moves.

• A cursor is a small symbol displayed on the computer screen (normally a diagonal arrow that is used as a pointer) that shows you what the mouse is referencing on the screen.

MouseMouse

PrinterPrinter

• A printer is designed to output information from a computer onto a piece of paper.

• There are three kinds of printers:

dot matrix, laser, and inkjet.

ScannerScanner

• A scanner is a device used to copy an image off paper and convert it into a digital image, which can be saved as a computer file and stored on a hard drive.

• Scanners can also use a special kind of technology called Optical Character Recognition (OCR) to read text from paper and save it as an editable document file

Session # 2Session # 2

Inside The CPU Inside The CPU CabinetCabinet

A Look Inside.A Look Inside.

Floppy

power supply

hard drive

motherboard

A Look Inside ..

CD-ROM drive

floppy drive

A Look Inside…A Look Inside…

• Identify all the major components:– Power Supply– Motherboard– Memory– Card Slots – Cards (sound, video, network)– CPU, heatsink and fan– Drives (floppy, hard and CD-ROM)

What these components do.What these components do.

• Power Supply – (heart) supplies power to all the circuitry and devices.

• Motherboard – (body) acts as a manager for everything on the computer – connects all the other components together.

• CPU – Central Processing Unit – (brain) this does all the work of computing.

What these components do..What these components do..

• RAM – Random Access Memory – (short-term memory) holds data and program instructions that the computer is currently using.

• Hard Drive – (long-term memory) holds all of the information that needs to be stored between uses of the computer.

• Floppy and CD-ROM drives – (mouth/ears) allow

you to give data to the computer and take data away from the computer.

What these components do…What these components do…

• Card Slots – (fingers) Allows other components to be added to the computer.

• Video card – (face) Does all of the processing necessary to get stuff looking nice on screen, quickly.

• Sound card – (vocal cords) Allows sounds from HD or CD-ROM to be played.

• Network Card – (telephone) allows computer to talk to other computers over a wire.

Power SupplyPower Supply

SMPS – Switch Mode Power Supply Switching Transistors

Outputs + 5V, -5V, +12 V, -12 V

Typical Costs are:• ATX – Rs.700• Non ATX – Rs.300

Usually, SMPS comes with the CPU Cabinet.

MotherbMotherboardoard

CPUCPU

Examples: Intel Family – Pentium 4, 3, 2, Pentium, XEON, Itanium AMD -- Athlon, K62 IBM -- Cyrix Motorola -- 68000 Series

MemoryRegisters

• A Single Chip

RAMRAM

Hard DriveHard Drive

We won’t remove this.

Floppy DriveFloppy Drive

CD-ROM Drive

Ribbon CablesRibbon Cables

polarized

Video Card

Sound Card

Back of Back of ComputerComputer

Remove these screws

End of Session # 2End of Session # 2

Queries???Queries???

CPUCPU

• The central processing unit or (CPU) is the "brain" of your computer. It contains the electronic circuits that cause the computer to follow instructions from memory.

• The CPU contains three main parts, all housed in a single package (Chip):

– Control Unit (CU)– Arithmetic Logic Unit (ALU)– Memory

Session # 3

Computer Peripherals

Major PeripheralsMajor Peripherals

• Keyboard• Mouse• Hard Disk• Floppy Disk• CD ROM• Printer• Scanner• Joystick

KeyboardKeyboard• Keypad contains:

– Alphabets– Numbers– Special Symbols– Function Keys

• qwert Keyboard (Typewriter Keyboard).• On key press it sends a code (ASCII Code) to the CPU.• Plug N Play device.• Typical Cost is Rs.300 – Rs.1200

MouseMouse

• Pointing & Click Device.

• Two / Three Buttons

• Wheel / Optical Mouse

• Normally Left Click – Select/ Run

Right Click – Popup Menu

• Typical Cost is Rs.100 – Rs1000

Hard DiskHard Disk

• Magnetic Memory Device.

• Non-removable storage device.

• Several Circular Magnetic Disks are housed in a

single case.

• Data is stored as 1s & 0s.

• Typical Capacity is 20 GB -80 GB

• Typical Cost is Rs.2200 – Rs6000

• Cost/Bit is Low.

Floppy DiskFloppy Disk

• Magnetic Memory Device.

• Removable storage.

• A single circular mylar plastic disk, coated with magnetic

material is packed in a protective plastic casing.

• Typical size is 3.5” & Capacity is 1.44MB

• Typical Costs are:

• Floppy Drive -- Rs.300

• Floppy Disk -- Rs.10

CD ROMCD ROM

• Optical Device.

• Removable Storage.

• Read Only Memory.

• Typical Capacity is 550 Mb – 800MB

• Typical Costs are:

• Drive -- Rs.1000

• Disk Rs10 – Rs.35• Related Terms:

• CD Writer

• WORM

• CD RW

PrinterPrinter

• Output Device, Produces Hard Copy• Types:

– Dot Matrix – Inkjet – Laser

• Typical Cost Ranges from Rs.3500 – Rs.2 lacs• Related Terms:

– Impact – Non Impact– Ribbon, Cartridge, Toner, Duty Cycle

• Major Vendors in India:– HP, Cannon, Samsung, TVS, Epson etc.

ScannerScanner

• Input Device, Converts a hard copy into a computer file.

• Used to Scan Signatures, Photographs etc.• Optical Device.• Typical Cost Rs.4000 – Rs.75000• Major Vendors in India:

– HP, Umax, Cannon• Nowadays Scanners with OCR produces

editable documents.

End of Session #3End of Session #3

Queries???

Session - 4Session - 4

Overview of Operating SystemOverview of Operating System

What is Operating System What is Operating System

OS is system software, which may be viewed as collection of software consisting of procedures for operating the computer.

It provides an environment for execution of programs (application software).

It’s an interface between user & computer.

Computer Machine (Hardware)

User / Programmer

Operating System

Human Understandable Language (High Level

Language)

Machine Language (Low Level Language)

Types of OS Types of OS

Multiprogramming OS

Multitasking/Multiprocessing

Multiuser OS

Time Sharing OS

Real Time OS

Distributed OS

A Second ClassificationA Second Classification

This Classification is based on the type of interface Operating System provides for the user to work in.

Character User Interface (CUI)

The User has to type the commands on the command prompt to get the work completed.

Ex. DOS, UNIX.

Graphical User Interface (GUI)The User need not type any commands.

He/She just point and clicks on the desired Icon to get the work done.

Ex. Windows (9X, XP, NT, 2000), Linux.

Functions of OSFunctions of OS

File Management

Memory Management

Process Management

Device Management

Types of ProcessingTypes of Processing

Serial ProcessingThe job is processed at the time

when it is submitted.

Batch Processing The similar jobs are bunched together and are kept for processing at an later time.

MS-DOS OverviewMS-DOS Overview

MS-DOS is an acronym for MicroSoft Disk Operating System

It is a CUI based operating system.

It provides user with a command prompt (generally called as C:\) where various command could be typed.

When one operates in the DOS environment, one interacts with the command interpreter, which interprets the commands given by user.

It provides an environment for execution of various application programs like MS-Word, MODBANKER, ISBS etc.

What is CommandWhat is Command

It is a string of characters which tells the computer what to do.

When one types commands to a computer, one is conversing with the operating system's command interpreter.

For example, to copy a file called file.txt from the 3-1/2" floppy drive to the hard drive, one could type

C:\> copy a:\file.txt c:\

The word "copy" is a DOS command which causes files to be copied from one location to another

Entering the DOS EnvironmentEntering the DOS Environment If the OS is DOS then the system will directly show prompt (C:\>)

If the OS is windows one must either terminate the Windows environment, or open a DOS shell within the Windows environment.

Ist Method: Terminating Windows Environment

Select “Restart in MS-DOS Mode” from Shut Down in Start Menu.

IInd Method: Opening DOS Shell in Windows

Select Start>Programs>Accessories>Command Prompt (XP)Start>Programs>Accessories>MS-DOS Prompt (98)

Files and DirectoryFiles and Directory

Files A file is a collection of Records. It is the smallest unit of File System (Storage) in a computer. Any document created using computer is a file. This document could either be

a letter, any excel sheet, any image or even a database.

Directory A collection of files is directory (in DOS) or folder (in Windows) It is analogous to the Office Folder which contains various documents. A directory/folder eases the management of related files/ documents, like the

various circulars related to personnel could be placed in a directory called “personnel” and all the circulars related to loans could be placed in a directory called “loans”.

Filenames in DOS?Filenames in DOS?

The filename in DOS have the following format. <name>.<ext>

It has two parts the name and the extension.

The name could be of 8 characters and the extension of 3 characters.

The filename can contain alphabets and numbers. It cannot contain any special character other than underscore (_) and also no spaces.

Organization of files in DOSOrganization of files in DOS

The DOS file system is a hierarchical file system.

Files are collected into directories, and directories may contain both files and other directories.

There is always a directory which is not contained by any other, called the root which is represented by the backslash '\' character.

Organization of files in DOS (Contd.)Organization of files in DOS (Contd.)

Concept of Path: Every file can be specified by enumerating all of the directories between the root and it, separated by the backslash '\' character, and appending the file name to the end.

The drive which contains the root is specified at the head of the path, separated from the root by a colon (':')

The hard drive is most commonly known as the C: drive, and the floppy drives are usually called A:(3-1/2 inch) and B: (5-1/4 inch).

Organization of files in DOS (Contd.)Organization of files in DOS (Contd.)

circulars loans personnel

january february

retire.txt

rest.txt abc.txt

officer.txt new.dat

Fig. Hierarchical Structure of Files

Some DOS CommandsSome DOS Commands

dir: Listing of all the directories.C:\> dir

cls: Clears the screen.C:\> cls

copy con: Creates a file.C:\> copy con <filename> < Write your Contents Here>Press Ctrl-Z (^Z) to finish writing.

Ex: C:\> copy con test.datLets Make UCO a top class Bank.Ctrl-Z (^Z) 1 file(s) copied. (A Message will be shown on the system)

This will create a file named test.dat having some data.

Some DOS Commands (Contd.)Some DOS Commands (Contd.)

edit: Edits a file.

C:\> edit <filename>This will open a editor window where the contents of file can be seen. These contents could also be edited here and on saving, the contents of file will change.

type: Displays the content of a file.

C:\> type <filename>This will display the contents of file on the computer. The contents of file could only be viewed but could not be changed, as in the case of edit.

md: Make Directory.

C:\> md (directory name>This will create a directory with the specified name.

cd: Change Directory.

C:\> cd (directory name>This will change the directory from current directory to the specified directory.

rd: Remove Directory.

C:\> rd (directory name>If the directory is needed to be removed permanently from the computer, use this command. For this command to be executed it is necessary that the directory should be empty and user should be on a directory above it.

copy: Copies a file.

C:\> copy <source> <destination>

This will copy the file from the source location to the specified destination. The command creates a copy of the file on the destination i.e. the file would be found on both the location.

move: Moves a file.

C:\> move <source> <destination>

This will move the file from the source location to the specified destination. The file from the source location would be removed and would be moved to the destination.

ren: Renames a file.

C:\> ren <old filename> <new filename>

This will change the name (rename) of the file to a new name as specified.

del: Deletes a file.

C:\> del <filename>

This will delete the file permanently from the system.

Overview of WindowsOverview of Windows

Windows is an GUI based operating system.

It is also developed by Microsoft Corporation, which is headed by Mr. Bill Gates.

Over the years the Microsoft have evolved various versions of Windows. Win95, Win98, Win2000, Win ME, Win NT, Win XP.

It gives user a handy environment where he doesn’t have to remember and learn the syntaxes of various commands as is the case in DOS.

The user can just point and click on the Icons provided to him on the screen.

Folders and DocumentsFolders and Documents

Folders are a way to organize your documents within drives in Windows as are the directories in DOS.

A document is each thing that you create on a computer. A document can be made using any type of software.

End of Session #4End of Session #4

Queries???

QUIZQUIZ

1. Name any four devices of a Computer.

Keyboard, Mouse, Scanner, Light Pen.

2. What is the job of CPU?

Central Processing Unit controls and coordinates all the activities of the computer.

QUIZQUIZ

3. What is the unit of measuring the speed of the processor?

Mega Hertz or Kilo Hertz ( No. of CPU Cycles/second)

4. What is a computer network?

It is interconnection of computers to make a LAN,MAN or WAN.

QUIZQUIZ

5. Name any three storage devices.

Hard Disk, Magnetic Tape, Compact Disk.

6. What is command to create directory?

C:\>MD <<dir-name>>

QUIZQUIZ

7. What is Internet?

It is the network of networks.

8. What are different types of printers?

Dot Matrix Printer, Inkjet

QUIZQUIZ

9.What is the use of Scanner?

It is used to copy the real image on paper to be stored as digital image in the computer.

10. Why Operating system is required?

It is required to provide the interface between the user and the computer.

QUIZQUIZ

11. What is the difference between Primary Storage and Secondary Storage?

Primary Storage is temporary storage, fast and costly.

Secondary storage is permanent, slow and

cheap.

QUIZQUIZ

12. What is MODEM. Why it is required?

It is Modulator Demodulator. It is used to connect the PC to the Internet using Analog Telephone Lines.

13. What is the maximum length of file name in DOS?

First Name- 8 characters, Last Name- 3 characters.

QUIZQUIZ

14. What is the command in DOS to see the contents of the file?

C:\> Type<<File Name>>

15. What are the two types of Software?

Systems Software

Application Software

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