2762 Computer-Introduction 2

8/22/2019 2762 Computer-Introduction 2

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8/3/2013 Introduction to Computers 1

CHAPTER -1


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Back ofComputer

Remove these screws


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End of Session # 2

Queries???


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CPU

The central processing unit or (CPU) is the "brain"of your computer. It contains the electronic circuitsthat cause the computer to follow instructionsfrom memory.

The CPU contains three main parts, all housed

in a single package (Chip):

Control Unit (CU)

Arithmetic Logic Unit (ALU)

Memory

BACK


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Session # 3Computer Peripherals


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Major Peripherals

Keyboard

Mouse

Hard Disk

Floppy Disk CD ROM

Printer

Scanner

Joystick


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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


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Mouse

Pointing & Click Device.

Two / Three Buttons

Wheel / Optical Mouse

NormallyLeft Click Select/ Run

Right Click Popup Menu

Typical Cost is Rs.100 Rs1000


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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.


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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


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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


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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.


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Scanner

Input Device, Converts a hard copy into acomputer 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.


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End of Session #3

Queries???


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Session - 4

Overview of Operating System


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What is Operating System

OS is system software, which may be viewed ascollection of software consisting of procedures foroperating the computer.

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

Its an interface between user & computer.


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Computer Machine

(Hardware)

User / Programmer

Operating System

Human Understandable Language(High Level Language)

Machine Language(Low Level Language)


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Types of OS

Multiprogramming OS

Multitasking/Multiprocessing

Multiuser OS

Time Sharing OS

Real Time OS

Distributed OS


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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 thecommand 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.


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Functions of OS

File Management

Memory Management

Process Management

Device Management


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Types of Processing

Serial Processing

The job is processed at the time when

it is submitted.

Batch Processing

The similar jobs are bunched together andare kept for processing at an later time.


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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 thecommand interpreter, which interprets the commands given by user.

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


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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 conversingwith 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 becopied from one location to another


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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, oropen a DOS shell within the Windows environment.

Ist Method: Terminating Windows Environment

Select Restart in MS-DOS Mode from Shut Down in StartMenu.

IInd Method: Opening DOS Shell in Windows

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


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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 aletter, 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 thevarious circulars related to personnel could be placed in a directory calledpersonnel and all the circulars related to loans could be placed in a directory

called loans.


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Filenames in DOS?

The filename in DOS have the following format.

.

It has two parts the name and the extension.

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

The filename can contain alphabets and numbers. It cannotcontain any special character other than underscore (_) andalso no spaces.


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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.


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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).


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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


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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

< 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.


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Some DOS Commands (Contd.)

edit: Edits a file.

C:\> edit

This will open a editor window where the contents of file can be seen. Thesecontents could also be edited here and on saving, the contents of file willchange.

type: Displays the content of a file.

C:\> type

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.


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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, usethis 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.


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copy: Copies a file.

C:\> copy

This will copy the file from the source location to the specified destination. Thecommand creates a copy of the file on the destination i.e. the file would befound on both the location.

move: Moves a file.

C:\> move

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


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ren: Renames a file.

C:\> ren

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

specified.

del: Deletes a file.

C:\> del

This will delete the file permanently from the system.


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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 doesnt 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.


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Folders and Documents

Folders are a way to organize your documents within drives in Windows asare 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.


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End of Session #4

Queries???


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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.


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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 aLAN,MAN or WAN.


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QUIZ

5. Name any three storage devices.

Hard Disk, Magnetic Tape, Compact Disk.

6. What is command to create directory?

C:\>MD


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QUIZ

7. What is Internet?

It is the network of networks.

8. What are different types of printers?

Dot Matrix Printer, Inkjet

Laser


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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 interfacebetween the user and the computer.


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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.


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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.


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QUIZ

14. What is the command in DOS to see the

contents of the file?

C:\> Type

15. What are the two types of Software?

Systems Software

Application Software