computer_IntroductionComputer introduction

Session - 1

Basics Of Computers

“ Ehsan Ullah “ [email protected]

[email protected]

mailto:[email protected]

mailto:[email protected]

11/5/2014 Introduction to Computers 2

A Desktop Machine


A Computer System

• Hardware

• Software

• User

Hardware

Software

User


A Computer System (Contd.)

• In general, a computer is a machine which

accepts data, processes it and returns new

information as output.

Data Information

Processing


Software

• 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 (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 (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 Computers

• 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 Computers

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 Computers

On the basis of Computing Power & Size:

• Laptop / Palmtop

• Micro Computer / Desktop

• Mini Computer / Mainframe

• Super Computer


Language of Computers

• 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 Network

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

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


Types Of Computer Networks

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 Networks

• Information Sharing

• Device Sharing

• Load Sharing

• Mobility

• Fast Communication

• Anywhere Anytime Banking


Internet

• 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 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)

• 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).


Keyboard

• 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.

Mouse


Printer

• 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.


Scanner

• 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 # 2

Inside The CPU Cabinet


A Look Inside.

Floppy

CD


power

supply

hard

drive

motherboard

A Look Inside ..

CD-ROM

drive

floppy

drivecards


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.

• 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..

• 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…

• 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 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.


Motherboard


CPU

Examples: Intel Family – Pentium 4, 3, 2, Pentium,

XEON, Itanium

AMD -- Athlon, K62

IBM -- Cyrix

Motorola -- 68000 Series

CU

ALU

Memory

Registers

• A Single Chip


RAM


Hard Drive

We won’t remove this.


Floppy Drive


CD-ROM Drive


Ribbon Cables

polarized


Video Card


Sound Card


Back of Computer

Remove these screws



End of Session # 2

Queries???


CPU

• 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

BACK

Session # 3

Computer Peripherals


Major Peripherals

• Keyboard

• Mouse

• Hard Disk

• Floppy Disk

• CD ROM

• Printer

• Scanner

• Joystick


Keyboard

• 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


Mouse

• 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 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 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 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


Printer

• 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.


Scanner

• 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 #3

Queries???

Session - 4

Overview of 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

Multiprogramming OS

Multitasking/Multiprocessing

Multiuser OS

Time Sharing OS

Real Time OS

Distributed OS


A 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 OS

File Management

Memory Management

Process Management

Device Management


Types of Processing

Serial Processing

The 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 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 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 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 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?

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 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.)

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.)

/

circulars loans personnel

january february

retire.txt

rest.txt abc.txt

officer.txt new.dat

Fig. Hierarchical Structure of Files


Some 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.dat

Lets 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.)

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 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 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 #4

Queries???


QUIZ

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.


QUIZ

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.


QUIZ

5. Name any three storage devices.

Hard Disk, Magnetic Tape, Compact Disk.

6. What is command to create directory?

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


QUIZ

7. What is Internet?

It is the network of networks.

8. What are different types of printers?

Dot Matrix Printer, Inkjet

Laser


QUIZ

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.


QUIZ

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.


QUIZ

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.


QUIZ

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

Technology

computer_IntroductionComputer introduction