TyroCity: Computer 11 Notes

Interrupt

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

It is the events that makes the processor stop executing its program to perform some requested activity. There are two types of interrupts they are:

1. Hardware interrupt:
Interrupts generated by hardware devices such as keyboard, mouse, printer or chips on the system board is called hardware interrupt. Some examples of hardware interrupt are video card wants memory access, USB scanner has data, mouse moves, key pressed on keyboard, etc.

2. Software interrupt: Interrupts signals generated or caused by the programs or software are called software interrupts. Some examples: interrupt generated by the ROM BIOS during the start up for the computer, virus threat notification by the antivirus software, etc.

Communication Port

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

It is a hardware device used for connecting peripherals devices with the computer. It has major functions like:

Connecting peripheral devices.
Transmitting data to and fro from peripheral devices.
Providing electrical power to the small peripheral devices.

Some of the communication ports used are:

- Serial port
It is used for connecting slow speed devices like keyboard, mouse, etc. It also provides electrical power supply to these devices. It cam transmit 1 bit data at a time.

- Parallel port
It is used for connecting medium speed devices like monitor, printer, etc. It can transmit 8 bit data at a time.

- USB (Universal serial bus)
USB is the common interface developed by multiple hardware developers for supporting large variables of devices. It is used to connect keyboard, monitor, pen drive, etc. It is the most common user interface at present.

- SCSI
It is used for connecting external memory devices like magnetic tape, multiple hard disk, etc.

- IEEE 1394 interface
This interface is used for connecting high speed devices like connecting audio/video equipments, aeronautical devices, medical equipments, etc.

- PCI (Peripheral communications interface)
It is used for connecting peripheral devices like internal modem, internal TV card, sound card, graphics card, etc with the computer. It is available in the mother board.

Secondary Memory

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

It is also known as external memory/S=storage memory/auxiliary memory/backup memory. It is used for storing data and instructions permanently. It is also used for carrying data from one computer to another. Secondary memory is not directly accessible to CPU. It is usually slower for read/write, cheaper and used in larger storage capacity.
Example: Hard disk, CD, DVD, Pen drive, etc.

Types of Secondary memory are:

Magnetic memory
Optical memory

1. Magnetic memory
Magnetic memory uses the property of magnet for storing data. It is in use since first generations of computer. It contains data storing surface coated by magnetic oxide. Magnetic memory is further divided as:

- Magnetic drum
Magnetic drum contains a metallic drum coated by magnetic oxide on the outer surface of the drum, data is stored in this surface. It was in use in first and second generations of computer.

- Magnetic tape
Magnetic tape contains thin plastic ribbon, only one side of the ribbon is used for storing data. The data storing side is coated by magnetic oxide. It is a sequential access memory. So, the data read/write speed is slower. It is mainly used for storing audio, video and back-up data. It is highly reliable. It requires magnetic tape drive for reading and writing data. It has the storage capacity of 100MB-200GB. The width of the ribbon also varies from 4mm-1inch.

- Magnetic disk
Magnetic disk contains a circular disc made of metal or plastic. Both side of the disc is usually used for storing data. The disc is coated by magnetic oxide. The disc is divided into multiple concentric circles known as track. Tracks are further divided into small area known as sectors. Data are stored in sectors.
Example: Hard disk, floppy disk, zip disk, super disk, Winchesterdisk, jaz disk.

- Hard disk
It is used as main storage device of the computer. It uses 2-4 metallic disk (platter). The disk is usually made of aluminum. Both sides of the disk is used for storing data except the upper side of the uppermost disk and lower side of the lowermost disk. The data storing surface is coated by magnetic oxide. Each data storing surface contains separate read/write head. During data read/write process platter rotates at the rate of 3600-15000rpm. Hard disk is also known as hard drive because both data storing disk and data read/write components are combined together. It has the storage capacity of few mega bytes to tera byte.

- Floppy disk
It contains single plastic disk. Initially it was used as a main storage device but nowadays it is used for carrying data from one computer to another. It requires floppy drive for its operation. It is not reliable as hard disk because the data storing surface is exposed. So, it may be affected by dust particles and magnetic field.

2. Optical memory
Optical memory uses light beam for its operation. It is developed in fourth generation of computer. It is mainly used for storing audio/video, backup as well as for carrying data. It requires optical drive for its operation. Its read/write speed is slower compared to hard disk and flash memories.
Example: CD, DVD, BD

CD
It stands for Compact Disk. It has storage capacity of 700 MB or approximately 90 minutes of standard audio. CD contains hard circular plastic, single side of this plastic is coated by aluminum alloy. This alloy stores data. It is protected by additional thin plastic covering. CD required CD drive for its operation. Types of CD are:
CD-R is a blank CD in which data can be stored once. After storing data it is converted into CD-ROM.
CD-ROM
It cannot be erased or updated
CD-RW
it can be erased and used for multiple times.
DVD
It stands for Digital Versatile Disk. It has the storage capacity of 4.7GB to 17GB. Its shape and size is similar to CD but the difference in storage capacity is due to different chemical component and data is compressed before storing. It requires DVD drive for its operation. Read/write speed of DVD is slower than that of CD. Types of DVD are:

DVD-R
DVD-ROM
DVD-RW

DVD can also be classified as:

Single sided single layered DVD (4.7GB)
Single sided dual layered DVD (7-8GB)
Dual sided single layered DVD (9GB)
Dual sided dual layered DVD (17GB)

BD
It stands for Bluray disk. It has the storage capacity of 25GB-50GB. It requires BD drive for its operation. Its shape and size is similar to CD and DVD. Types of BD are:

BD-R
BD-ROM
BD-RW

Working mechanism of CD
The surface of the CD contains land and pit. Land represents binary 1 and pit represents binary 0. During CD reading process a beam of light is emitted which strikes the surface of CD and gets reflected. The reflection is captured by lens in the CD drive. Difference in reflection from land and pit is identified to determine 1 and 0. Land is actually in a crystalline form and pit is in amorphous form. The size of land and pit is smaller in DVD compared to CD.
External memory devices:

1. Zip disk
It is a magnetic memory. It is thee modification of floppy disk. It has the storage capacity of 100MB and 250MB. It requires Zip disk drive for its operation.

2. Jaz disk
It is also a magnetic memory. It has the storage capacity of 2GB. It also requires separate Jaz disk drive for its operation.

3. Super disk
It is also a magnetic memory. It has the storage capacity of 120MB. It requires Super disk drive for its operation. Both floppy and super disk can be used in super disk drive.

4. Pen drive
It is a flash memory. It is a semi-conductor memory. It is mainly used for transferring data. It has faster read/write speed compared to magnetic memory. Pen drive has storage capacity of few MB-GB. A pen drive is a plug and play device. A pen drive can be connected with the computer through USB port.

5. Portable hard disk
it is a magnetic hard disk. It can be connected with the computer through the USB port. It is also a plug and play device. It is mainly used for storing backup. It has the storage capacity from few GB-TB

Introduction To MS-Word

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Introduction to Microsoft Word
Let us consider an office scene. Many letters are typed in the office. The officer dictates a letter. The typist first types a draft copy of the letter. The officer goes through it to check mistakes regarding spelling errors, missing words, etc. and suggests corrections. The typist changes the letter as suggested by the officer. This is a simple example of word processing.
There are many software packages to do the job of word processing. Some of them work in dos environment. Example are WordStar, Word Perfect and Professional Write. But in these days working in windows is becoming more and more popular. So let us consider software for word processing which works in windows. Our choice is Microsoft Word because it is the most popular software in these days.
MS-word is a part of the bigger package called Microsoft office, which can do much more than word processing. In fact when you open up Microsoft office you will find four main components in it. They are Microsoft Word (for word processing), Microsoft Excel (for spreadsheet), Microsoft Access (for database management) and Microsoft PowerPoint (for presentation purposes). However, we will limit ourselves to MS-word only in this lesson.

Objectives

After going through this lesson you should be in a position to:

Start the Microsoft Word package
Be familiar with the Microsoft Word screen
Advantages and Features of Word Processing
Some common Word Processing Packages
How to invoke Microsoft Word
Learn the capabilities of Microsoft Word

What is word processing?
Word Processor is a Software package that enables you to create, edit, print and save documents for future retrieval and reference. Creating a document involves typing by using a keyboard and saving it. Editing a document involves correcting the spelling mistakes, if any, deleting or moving words sentences or paragraphs.

Advantages of word processing
One of the main advantages of a word processor over a conventional typewriter is that a word processor enables you to make changes to a document without retyping the entire document.

Features of word processing
Most Word Processor available today allows more than just creating and editing documents. They have wide range of other tools and functions, which are used in formatting the documents. The following are the main features of a Word Processor:

Text is typing into the computer, which allows alterations to be made easily.
Words and sentences can be inserted, amended or deleted.
Paragraphs or text can be copied /moved throughout the document.
Margins and page length can be adjusted as desired.
Spelling can be checked and modified through the spell check facility.
Multiple document/files can be merged.
Multiple copies of letters can be generated with different addresses through the mail-merge facility.

Some Common Word processing packages
The followings are examples of some popular word processor available

Softword
WordStar
Word perfect
Microsoft word

Important feature of Microsoft Word
Microsoft word not only supports word processing features but also DTP features. Some of the important features of Microsoft Word are listed below:

Using word you can create the document and edit them later, as and when required, by adding more text, modifying the existing text, deleting/moving some part of it.
Changing the size of the margins can reformat complete document or part of text.
Font size and type of fonts can also be changed. Page numbers and Header and Footer can be included.
Spelling can be checked and correction can be made automatically in the entire document. Word count and other statistics can be generated.
Text can be formatted in columnar style as we see in the newspaper. Text boxes can be made.
Tables can be made and included in the text.
Word also allows the user to mix the graphical pictures with the text. Graphical pictures can either be created in word itself or can be imported from outside like from Clip Art Gallery.
Word also provides the mail-merge facility.
Word also has the facility of macros. Macros can be either attached to some function/special keys or to a tool bar or to a menu.
It also provides online help of any option.

In-text questions 1

1. State True or False

Word processor is Software Package that enables you to create, edit, print and save document.
WordStar is a popular Word processor.
Changing the size of the margins cannot reformat complete document or part of the text.
Word has the facility of Macros.
Word does not allow the user to mix the graphical pictures with text.

Getting started with Microsoft Word
We have already told you that for working in MS-Word you should be familiar with windows. If you have not covered windows so far then read that first and then go through MS-word. By now you must be aware of the fact that a software package is improved from time to time. These improvements are sold in the market as new versions of the same software. Thus you will find many versions of Microsoft Word being used in different offices. In this lesson we will cover the version Microsoft Word 97, which is latest in the market and contain many improvements over the older versions. However, you do not have to worry if you have an older version such as word 6.0 or word 95. All the commands available in these older versions are also available in word 97 and they are compatible.
While working in Microsoft Word you have to work with a mouse. Also one can work, to some extent, through the keyboard. The use of mouse is simpler as it is fully menu driven. In MS-word every command is available in the form of ‘icons’.

You can go inside MS-word by the following way:

Take the mouse pointer to start button on the task bar. Click the left mouse button.
Move the pointer to programs. You will notice another menu coming up to the right.
In that menu identify where Microsoft word is placed. Move the cursor horizontally to come out of programs.
Move into the rectangular area meant for Microsoft word. Click the left mouse button there. The computer will start MS-word.

Let us discuss the important components of the screen.

- Title bar
The title bar displays the name of the currently active word document. Like other windows applications, it can be used to alter the size and location of the word window.

- Tool bars
Word has a number of tool bars that help you perform task faster and with great ease. Two of the most commonly tool bars are the formatting tool bar and the standard tool bar. These two toolbars are displayed just below the title bar. At any point of time any tool bar can be made ON or OFF through the tool bar option of View Menu.

- Ruler bar
The Ruler Bar allows you to format the vertical alignment of text in a document.

- Status bar
The Status Bar displays information about the currently active document. This includes the page number that you are working, the column and line number of the cursor position and so on.

- Scroll bar
The Scroll Bar helps you scroll the content or body of document. You can do so by moving the elevator button along the scroll bar, or by click in on the buttons with the arrow marked on them to move up and down and left and right of a page.

- Workspace
The Workspace is the area in the document window were you enter/type the text of your document.

- Main menu
The Word main menu is displayed at the top of the screen as shown in the Fig. 9.1. The main menu further displays a sub menu. Some of the options are highlighted options and some of them appear as faded options. At any time, only highlighted options can be executed, faded options are not applicable. Infect if the option is faded you will not be able to choose it. You may not that any option faded under present situation may become highlighted under different situations.

In-text questions 2
1. Choose the best answer.

1. While working in MS-Word you have to work with

Mouse only
Keyboard only
Both mouse and keyboard

2. In Microsoft Word every command is available in

Print
Letter
Icons

3. You can go inside Microsoft Word by the following way

Take the mouse pointer to start button on the task bar and click the left mouse button.
Take the mouse pointer to start button and click the right mouse button.
Move the mouse pointer on the screen.

2. State True or False

The title bar displays the name of the currently active word document.
Two of the most commonly tool bars are the formatting tool bar and the standard tool bar.
The tool bar allows you to format the vertical alignment of text.
The scroll bar helps you to scroll the content or body of document.
The workspace is the area in the document window where you enter/type the text.

Main menu options

The overall functions of all the items of main menu are explained below.

- File
You can perform file management operations by using these options such as opening, closing, saving, printing, exiting etc.
New: Ctrl+N
Open: Ctrl+O
Close: ALT + F4
Save : Ctrl+S
Save Aa: CTL + A
Print: Ctrl+P

File sub menu

- Edit
Using this option you can perform editing functions such as cut, copy, paste, find and replace etc.
Undo Clear: Ctrl+Z
Repeat Clear: Ctrl+Y
Cut: Ctrl+X
Copy: Ctrl+C
Paste: Ctrl+V
Clear: Delete
Select All: Ctrl+A
Find: Ctrl+F
Replace: Ctrl+H
Go To: Ctrl+G

Edit sub menu

- View
Word document can be of many pages. The different pages may have different modes. Each mode has its limitations. For example in normal mode the graphical picture cannot be displayed. They can only be displayed in page layout mode. Using the option “View” you can switch over from one mode to other. It displays the following Sub menu.

Normal

Online Layout
Page Layout
Outline
Master Document

Tool Bars

Ruler

Header and Footer

Footnotes
Comments
Full Screen
Zoom

- Insert
Using this menu, you can insert various objects such as page numbers, footnotes, picture frames etc. in your document. It displays the following Sub menu.

Break
Page Numbers
Date and Time
AutoText 8

Field…
Symbol…
Comment
Footnote…
Caption…
Cross-reference…
Index & Tables…
Picture 8
Text Box…
File…
Object…
Bookmark Hyperlink… Ctrl+k

- Format
**Using this menu, you can perform various type of formatting operations, such as fonts can be changed, borders can be framed etc. It displays the following Sub menu.

Font…

Paragraph…
Bullets and Numbering
Borders and Shading…

Columns…

Tabs…
Drop Cap…
Text Direction…
Change Case…
Auto Format…
Style Gallery…
Style…
Background…

Object

- Tools
Using this menu, you can have access to various utilities/tools of Word, such as spell check, macros, mail merge etc. It displays the following Sub menu.
Spelling and Grammar…

Language…
Word count…
AutoSummarize
Auto correct..
Look up reference

Track change

Merge Documents…
Protect Document…
Mail Merge…

Envelops and Labels…

Letter wizard…
Macro…
Templates and add-ins…
Customize…
Options…

- Table
This menu deals with tables. Using this menu you can perform various types of operations on the table. It displays the following Sub menu.

Draw Table
Insert Table…

Delete cells…
Merge cells…
Split cells…

Select Row

Select column
Select table

Table Auto Format…

Distribute rows evenly
Distribute columns evenly
Cell height and width…
Headings

Convert Text to table…

Sort …
Formula…
Split table
Hide grid lines

- Window
This menu allows you to work with two documents simultaneously. This would require two windows to be opened so that each one can hold one document. Using this menu, you can switch over from one window to another. It displays the following Sub menu.

New Window

Arrange all
Split
1Document1.doc

- Help
Using this menu, you can get on-line help for any function.

In-text question 3

1. State True or False

Using View option you can perform editing functions such as cut, copy, paste, find and replace etc.
Using the Edit option you can switch over from Normal mode to Out line mode.
Using Insert menu you can insert various objects such as page numbers, footnotes, picture frames etc.
Using Tools menu you can access to various utilities of word such as spell check, macros and mail merge etc.
Window menu allows you to work with two documents simultaneously.

What you have learnt
At the end of this lesson you have learnt the important features of Ms-Word. We started with procedure to invoke Ms-Word. We identified toolbars available in the main menu of Ms-Word are discussed.

Terminal questions

What do you understand by Word processing? Give examples.
Describe the important features of Ms-Word.
Describe the various options available in the main menu bar of Ms-Word.
What are the different types of toolbar?
Define two methods to start Ms-Word.

Feedback to the in-text questions

In-text question 1

True
True
False
True
False

In-text question 2

3, 3,1
True, True, False, True, True

In-text question 3

False
False
True
True
True

Language/Software

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Introduction

In the previous lesson we discussed about the different parts and configurations of computer. It has been mentioned that programs or instructions have to be fed to the computer to do specific task. So it is necessary to provide sequence of instructions so that your work can be done. We can divide the computer components into two major areas, namely, hardware and software. Hardware is the machine itself and its various individual equipment. It includes all mechanical, electronic and magnetic devices such as monitor, printer, electronic circuit, floppy and hard disk. In this lesson we will discuss about the other part, namely, software.

Objectives

After going through this lesson you will be able to

explain the concept of software
distinguish between different types of software
differentiate application software from system software
define a language
differentiate between different types of language
distinguish between compiler and interpreter

What is software?

As you know computer cannot do anything without instructions from the user. In order to do any specific job you have to give a sequence of instructions to the computer. This set of instructions is called a computer program. Software refers to the set of computer programs, procedures that describe the programs, how they are to be used. We can say that it is the collection of programs, which increase the capabilities of the hardware. Software guides the computer at every step where to start and stop during a particular job. The process of software development is called programming.

You should keep in mind that software and hardware are complementary to each other. Both have to work together to produce meaningful result. Another important point you should know that producing software is difficult and expensive.

Software types

Computer software is normally classified into two broad categories.

Application Software
System software

Application software: Application Software is a set of programs to carry out operations for a specific application. For example, payroll is an application software for an organization to produce pay slips as an output. Application software is useful for word processing, billing system, accounting, producing statistical report, analysis of numerous data in research, weather forecasting, etc. In later modules you will learn about MS WORD, Lotus 1-2-3 and dBASE III Plus. All these are application software.

Another example of application software is programming language. Among the programming languages COBOL (Common Business Oriented Language) is more suitable for business application whereas FORTRAN (Formula Translation) is useful for scientific application. We will discuss about languages in next section.

System software: You know that an instruction is a set of programs that has to be fed to the computer for operation of computer system as a whole. When you switch on the computer the programs written in ROM is executed which activates different units of your computer and makes it ready for you to work on it. This set of program can be called system software. Therefore system software may be defined as a set of one or more programs designed to control the operation of computer system.

System software are general programs designed for performing tasks such as controlling all operations required to move data into and out of the computer. It communicates with printers, card reader, disk, tapes etc. monitor the use of various hardware like memory, CPU etc. Also system software are essential for the development of applications software. System Software allows application packages to be run on the computer with less time and effort. Remember that it is not possible to run application software without system software.

Development of system software is a complex task and it requires extensive knowledge of computer technology. Due to its complexity it is not developed in house. Computer manufactures build and supply this system software with the computer system. DOS, UNIX and WINDOWS are some of the widely used system software. Out of these UNIX is a multi-user operating system whereas DOS and WINDOWS are PC-based. We will discuss in detail about DOS and WINDOWS in the next module.

So without system software it is impossible to operate your computer.

In-text questions 1

1. What are program, programming and software?

2. Differentiate between system software and application software.

3. Write True or False

The set of instructions given to the computer is called programming.
Application Software is a set of programs to carry out operations for a specific application.
UNIX is a multi-user operating system.

What is language?

You are aware with the term language. It is a system of communication between you and me. Some of the basic natural languages that we are familiar with are English, Hindi, Oriya etc. These are the languages used to communicate among various categories of persons. But how you will communicate with your computer. Your computer will not understand any of these natural languages for transfer of data and instruction. So there are programming languages specially developed so that you could pass your data and instructions to the computer to do specific job. You must have heard names like FORTRAN, BASIC, COBOL etc. These are programming languages. So instructions or programs are written in a particular language based on the type of job. As an example, for scientific application FORTRAN and C languages are used. On the other hand COBOL is used for business applications.

Programming languages

There are two major types of programming languages. These are Low Level Languages and High Level Languages. Low Level languages are further divided in to Machine language and Assembly language.

Low Level Languages

The term low level means closeness to the way in which the machine has been built. Low level languages are machine oriented and require extensive knowledge of computer hardware and its configuration.

Machine Language

Machine Language is the only language that is directly understood by the computer. It does not needs any translator program. We also call it machine code and it is written as strings of 1’s (one) and 0’s (zero). When this sequence of codes is fed to the computer, it recognizes the codes and converts it in to electrical signals needed to run it. For example, a program instruction may look like this: 1011000111101

It is not an easy language for you to learn because of its difficult to understand. It is efficient for the computer but very inefficient for programmers. It is considered to the first generation language. It is also difficult to debug the program written in this language.

Advantage

The only advantage is that program of machine language run very fast because no translation program is required for the CPU.

Disadvantages

It is very difficult to program in machine language. The programmer has to know details of hardware to write program.
The programmer has to remember a lot of codes to write a program which results in program errors.
It is difficult to debug the program.

Assembly Language

It is the first step to improve the programming structure. You should know that computer can handle numbers and letter. Therefore some combination of letters can be used to substitute for number of machine codes.

The set of symbols and letters forms the Assembly Language and a translator program is required to translate the Assembly Language to machine language. This translator program is called `Assembler‘. It is considered to be a second-generation language.

Advantages:

The symbolic programming of Assembly Language is easier to understand and saves a lot of time and effort of the programmer.
It is easier to correct errors and modify program instructions.
Assembly Language has the same efficiency of execution as the machine level language. Because this is one-to-one translator between assembly language program and its corresponding machine language program.

Disadvantages:

One of the major disadvantages is that assembly language is machine dependent. A program written for one computer might not run in other computers with different hardware configuration.

In-text questions 2

1. What is the difference between FORTRAN and COBOL?

2. Differentiate between machine language and Assembly language.

3. Write True or False

Low level language and High level language are two major types of programming languages.
Machine language is the only language that is indirectly understood by the computer.
Assembly language is second generation language.

High level language

You know that assembly language and machine level language require deep knowledge of computer hardware where as in higher language you have to know only the instructions in English words and logic of the problem irrespective of the type of computer you are using.

Higher level languages are simple languages that use English and mathematical symbols like +, -, %, / etc. for its program construction.

You should know that any higher level language has to be converted to machine language for the computer to understand.

Higher level languages are problem-oriented languages because the instructions are suitable for solving a particular problem. For example COBOL (Common Business Oriented Language) is mostly suitable for business oriented language where there is very little processing and huge output. There are mathematical oriented languages like FORTRAN (Formula Translation) and BASIC (Beginners All-purpose Symbolic Instruction Code) where very large processing is required.

Thus a problem oriented language designed in such a way that its instruction may be written more like the language of the problem. For example, businessmen use business term and scientists use scientific terms in their respective languages.

Advantages of High level languages

Higher level languages have a major advantage over machine and assembly languages that higher level languages are easy to learn and use. It is because that they are similar to the languages used by us in our day to day life.

Compiler

It is a program translator that translates the instruction of a higher level language to machine language. It is called compiler because it compiles machine language instructions for every program instructions of higher level language. Thus compiler is a program translator like assembler but more sophisticated. It scans the entire program first and then translates it into machine code.

The programs written by the programmer in higher level language is called source program. After this program is converted to machine languages by the compiler it is called object program.

Higher level language

———————————- ® (Compile) ® Program Machine Language Program

A compiler can translate only those source programs, which have been written, in that language for which the compiler is meant for. For example FORTRAN compiler will not compile source code written in COBOL language.

Object program generated by compiler is machine dependent. It means programs compiled for one type of machine will not run in another type. Therefore every type of machine must have its personal compiler for a particular language. Machine independence is achieved by using one higher level language in different machines.

Interpreter

An interpreter is another type of program translator used for translating higher level language into machine language. It takes one statement of higher level languages, translate it into machine language and immediately execute it. Translation and execution are carried out for each statement. It differs from compiler, which translate the entire source program into machine code and does involve in its execution.

The advantage of interpreter compared to compiler is its fast response to changes in source program. It eliminates the need for a separate compilation after changes to each program. Interpreters are easy to write and do not require large memory in computer. The disadvantage of interpreter is that it is time consuming method because each time a statement in a program is executed then it is first translated. Thus compiled machine language program runs much faster than an interpreted program.

In-text question 3

1. What is the difference between interpreter and compiler

2. Give some examples of high level language.

3. Write True or False

High level languages are problem-oriented language.
Object program generated by compiler is machine independent.
The disadvantage of interpreter is that it is time consuming.

What you have learnt

In this lesson we discussed about two types of software, namely, system software and application software. System software controls the hardware part of the computer. It is designed for performing tasks such as controlling all operations required to move data into and out of the computer. It communicates with printer, card reader, disk, tapes, etc. and monitors the use of various components like memory, CPU, etc. DOS, Unix and Windows are three important system software. Application software is a set of programs written for specific purpose. Examples of application software are Microsoft Word, Lotus 1-2-3, COBOL, BASIC and FORTRAN. We have discussed about levels of computer language.

Terminal questions

What is software and hardware?
What is computer Language?
Name the three different categories of computer languages.
What is machine language? Why is it required?
What are advantages and disadvantages of machine language?
What is assembly language? What are its advantages over machine languages?
What is the difference between source program and object program?
What is higher level languages? Why are higher level languages are easier to use.
What is compiler? Why is it required?
What is interpreter? How does it differ from compiler?

Feedback to in-text questions

In-text questions 1

1. Program is a set of instructions given to the computer by the user. Software is a set of computer programs and procedures that describe the programs. Programming is the process of software development.

2. Application Software is a set of programs to carry out operations for a specific application. System software is a set of programs written for performing tasks such as controlling all operations required to move data into and out of the computer.

3. 1. False 2. True 3. True

In-text questions 2

1. FORTRAN is used for scientific applications whereas COBOL is used for business applications.

2. Machine Languages are the only language that is directly understood by the computer. It is written in binary form that is 0 and 1. The set of symbols and letters forms the Assembly Language.

3. 1. True 2. False 3. True

In-text questions 3

1. Both compiler and interpreter are program translators used for translating higher level language into machine language. While compiler scans the entire program first and then translates it into machine code, an Interpreter translates the program line by line.

2. FORTRAN (Formula Translation) and BASIC (Beginners All-purpose Symbolic Instruction Code) are some of the high level languages.

3. 1. True 2. False 3. True

Application Package | Computer Science | HSEB Notes

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Detailed notes to follow:

1. Word processor

Use & Character
Examples
Some Important Terms Used: Thesaurus, speller, mail merge

2. Spread sheet

Use & Character
Examples
Some Important Terms Used: Relative cell reference, absolute cell reference

3. Presentation

Use & Character
Examples

Programming Concept | Computer Science | HSEB Notes

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Detailed notes to follow:

- Types of programming language

1. Low level language

Machine Language (1GL)
Assembly Language (2GL)

2. High level language

Procedural-Oriented Language (3GL)
Problem-Oriented (Fourth Generation) Language (4GL)
Natural (Fifth Generation) Language (5GL)

- Language translator

Assembler
Compiler
Interpreter

- Syntax and semetics

Syntax Error
Sematic Error
Run-Time Error

- Flowchart

System Flowchart
Program Flowchart

Basic Concept Of Computer

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Introduction to computer

Let us begin with the word ‘compute’. It means ‘to calculate’. We all are familiar with calculations in our day to day life. We apply mathematical operations like addition, subtraction, multiplication, etc. and many other formulae for calculations. Simpler calculations take less time. But complex calculations take much longer time. Another factor is accuracy in calculations. So man explored with the idea to develop a machine which can perform this type of arithmetic calculation faster and with full accuracy. This gave birth to a device or machine called ‘computer’.

The computer we see today is quite different from the one made in the beginning. The number of applications of a computer has increased, the speed and accuracy of calculation has increased. You must appreciate the impact of computers in our day to day life. Reservation of tickets in Air Lines and Railways, payment of telephone and electricity bills, deposits and withdrawals of money from banks, business data processing, medical diagnosis, weather forecasting, etc. are some of the areas where computer has become extremely useful.

However, there is one limitation of the computer. Human beings do calculations on their own. But computer is a dumb machine and it has to be given proper instructions to carry out its calculation. This is why we should know how a computer works.

Objectives

After going through this lesson you will be in a position to

Define a computer
Identify characteristics of computer
Know the origin and evolution of computer
Identify capability of computer in terms of speed and accuracy
Distinguish computer from human beings and calculator
Identify the role of computer
Appreciate the evolution of computer through five generations

Computers

Computer is an electronic device. As mentioned in the introduction it can do arithmetic calculations faster. But as you will see later it does much more than that. It can be compared to a magic box, which serves different purpose to different people. For a common man computer is simply a calculator, which works automatic and quite fast. For a person who knows much about it, computer is a machine capable of solving problems and manipulating data. It accepts data, processes the data by doing some mathematical and logical operations and gives us the desired output.

Therefore, we may define computer as a device that transforms data. Data can be anything like marks obtained by you in various subjects. It can also be name, age, sex, weight, height, etc. of all the students in your class or income, savings, investments, etc., of a country. Computer can be defined in terms of its functions. It can:

Accept data
Store data
Process data as desired
Retrieve the stored data as and when required
Print the result in desired format. You will know more about these functions as you go through the later lessons

Characteristics of computer

Let us identify the major characteristics of computer. These can be discussed under the headings of speed, accuracy, diligence, versatility and memory.

Speed

As you know computer can work very fast. It takes only few seconds for calculations that we take hours to complete. Suppose you are asked to calculate the average monthly income of one thousand persons in your neighborhood. For this you have to add income from all sources for all persons on a day to day basis and find out the average for each one of them. How long will it take for you to do this? One day, two days or one week? Do you know your small computer can finish this work in few seconds? The weather forecasting that you see every day on TV is the results of compilation and analysis of huge amount of data on temperature, humidity, pressure, etc. of various places on computers. It takes few minutes for the computer to process this huge amount of data and give the result.

You will be surprised to know that computer can perform millions (1,000,000) of instructions and even more per second. Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second) or nano-second (10-9part of a second). From this you can imagine how fast your computer performs work.

Accuracy

Suppose some one calculates faster but commits a lot of errors in computing. Such result is useless. There is another aspect. Suppose you want to divide 15 by 7. You may work out up to 2 decimal places and say the dividend is 2.14. I may calculate up to 4 decimal places and say that the result is 2.1428. Some one else may go up to 9 decimal places and say the result is 2.142857143. Hence, in addition to speed, the computer should have accuracy or correctness in computing.

The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.

Diligence

A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.

Versatility

It means the capacity to perform completely different type of work. You may use your computer to prepare payroll slips. Next moment you may use it for inventory management or to prepare electric bills.

Power of remembering

Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose
or retrieve these data.

No IQ

Computer is a dumb machine and it cannot do any work without instruction from the user. It performs the instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can.

No feeling

It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users.

Storage

The Computer has an in-built memory where it can store a large amount of data. You can also store data in secondary storage devices such as floppies, which can be kept outside your computer and can be carried to other computers.

In-text questions 1

What is a computer? Why is it known as data processor?
What are the important characteristics of computer?

History Of computer

History of computer could be traced back to the effort of man to count large numbers. This process of counting of large numbers generated various systems of numeration like Babylonian system of numeration, Greek system of numeration, Roman system of numeration and Indian system of numeration. Out of these the Indian system of numeration has been accepted universally. It is the basis of modern decimal system of numeration (0, 1, 2, 3, 4, 5, 6, 7, 8, 9). Later you will know how the computer solves all calculations based on decimal system. But you will be surprised to know that the computer does not understand the decimal system and uses binary system of numeration for processing.

We will briefly discuss some of the path-breaking inventions in the field of computing devices.

Calculating Machines

It took over generations for early man to build mechanical devices for counting large numbers. The first calculating device called ABACUS was developed by the Egyptian and Chinese people.

The word ABACUS means calculating board. It consisted of sticks in horizontal positions on which were inserted sets of pebbles. A modern form of ABACUS is given in Fig. 1.2. It has a number of horizontal bars each having ten beads. Horizontal bars represent units, tens, hundreds, etc.

Napier’s bones

English mathematician John Napier built a mechanical device for the purpose of multiplication in 1617 A D. The device was known as Napier’s bones.

Slide rule

English mathematician Edmund Gunter developed the slide rule. This machine could perform operations like addition, subtraction, multiplication, and division. It was widely used in Europe in 16th century.

Pascal’s adding and subtractory machine

You might have heard the name of Blaise Pascal. He developed a machine at the age of 19 that could add and subtract. The machine consisted of wheels, gears and cylinders.

Leibniz’s multiplication and dividing machine

The German philosopher and mathematician Gottfried Leibniz built around 1673 a mechanical device that could both multiply and divide.

Babbage’s analytical engine

It was in the year 1823 that a famous English man Charles Babbage built a mechanical machine to do complex mathematical calculations. It was called difference engine. Later he developed a general-purpose calculating machine called analytical engine. You should know that Charles Babbage is called the father of computer.

Mechanical and electrical calculator

In the beginning of 19th century the mechanical calculator was developed to perform all sorts of mathematical calculations. Up to the 1960s it was widely used. Later the rotating part of mechanical calculator was replaced by electric motor. So it was called the electrical calculator.

Modern electronic calculator

The electronic calculator used in 1960 s was run with electron tubes, which was quite bulky. Later it was replaced with transistors and as a result the size of calculators became too small.

The modern electronic calculator can compute all kinds of mathematical computations and mathematical functions. It can also be used to store some data permanently. Some calculators have in-built programs to perform some complicated calculations.

In-text questions 2

What is the first mathematical device built and when was it built?
Who is called the father of Computer Technology.

Computer generations

You know that the evolution of computer started from 16th century and resulted in the form that we see today. The present day computer, however, has also undergone rapid change during the last fifty years. This period, during which the evolution of computer took place, can be divided into five distinct phases known as Generations of Computers. Each phase is distinguished from others on the basis of the type of switching circuits used.

First generation computers

First generation computers used Thermion valves. These computers were large in size and writing programs on them was difficult. Some of the computers of this generation were:

ENIAC: It was the first electronic computer built in 1946 at University of Pennsylvania, USA by John Eckert and John Mauchy. It was named Electronic Numerical Integrator and Calculator (ENIAC). The ENIAC was 30´50 feet long, weighed 30 tons, contained 18,000 vacuum tubes, 70,000 registers, 10,000 capacitors and required 150,000 watts of electricity. Today your favorite computer is many times as powerful as ENIAC, still size is very small.

EDVAC: It stands for Electronic Discrete Variable Automatic Computer
and was developed in 1950. The concept of storing data and instructions inside the computer was introduced here. This allowed much faster operation since the computer had rapid access to both data and instructions. The other advantages of storing instruction was that computer could do logical decision internally.

Other Important Computers of First Generation

EDSAC: It stands for Electronic Delay Storage Automatic Computer and was developed by M.V. Wilkes at Cambridge University in 1949.

UNIVAC-1: Ecker and Mauchly produced it in 1951 by Universal Accounting Computer setup.

Limitations of First Generation Computer

Followings are the major drawbacks of First generation computers.

The operating speed was quite slow.
Power consumption was very high.
It required large space for installation.
The programming capability was quite low.

Second generation computers

Around 1955 a device called Transistor replaced the bulky electric tubes in the first generation computer. Transistors are smaller than electric tubes and have higher operating speed. They have no filament and require no heating. Manufacturing cost was also very low. Thus the size of the computer got reduced considerably.

It is in the second generation that the concept of Central Processing Unit (CPU), memory, programming language and input and output units were developed. The programming languages such as COBOL, FORTRAN were developed during this period. Some of the computers of the Second Generation were

IBM 1620: Its size was smaller as compared to First Generation computers and mostly used for scientific purpose.
IBM 1401: Its size was small to medium and used for business applications.
CDC 3600: Its size was large and is used for scientific purposes.

Third generation computers

The third generation computers were introduced in 1964. They used Integrated Circuits (ICs). These ICs are popularly known as Chips. A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. So it is quite obvious that the size of the computer got further reduced. Some of the computers developed during this period were IBM-360, ICL-1900, IBM-370, and VAX-750. Higher level language such as BASIC (Beginners All purpose Symbolic Instruction Code) was developed during this period.

Computers of this generations were small in size, low cost, large memory and processing speed is very high.

Fourth generation computers

The present day computers that you see today are the fourth generation computers that started around 1975. It uses large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors. Due to the development of microprocessor it is possible to place computer’s central processing unit (CPU) on single chip. These computers are called microcomputers. Later very large scale Integrated Circuits (VLSIC) replaced LSICs.

Thus the computer which was occupying a very large room in earlier days can now be placed on a table. The personal computer (PC) that you see in your school is a Fourth Generation Computer.

Fifth generation computer

The computers of 1990s are said to be Fifth Generation computers. The speed is extremely high in fifth generation computer. Apart from this it can perform parallel processing. The concept of Artificial intelligence has been introduced to allow the computer to take its own decision. It is still in a developmental stage.

Types of computers

Now let us discuss the varieties of computers that we see today. Although they belong to the fifth generation they can be divided into different categories depending upon the size, efficiency, memory and number of users. Broadly they can be divided it to the following categories.

1. Microcomputer: Microcomputer is at the lowest end of the computer range in terms of speed and storage capacity. Its CPU is a microprocessor. The first microcomputers were built of 8-bit microprocessor chips. The most common application of personal computers (PC) is in this category. The PC supports a number of input and output devices. An improvement of 8-bit chip is 16-bit and 32-bit chips. Examples of microcomputer are IBM PC, PC-AT .

2. Mini Computer: This is designed to support more than one user at a time. It possesses large storage capacity and operates at a higher speed. The mini computer is used in multi-user system in which various users can work at the same time. This type of computer is generally used for processing large volume of data in an organization. They are also used as servers in Local Area Networks (LAN).

3. Mainframes: These types of computers are generally 32-bit microprocessors. They operate at very high speed, have very large storage capacity and can handle the work load of many users. They are generally used in centralized databases. They are also used as controlling nodes in Wide Area Networks (WAN). Example of mainframes are DEC, ICL and IBM 3000 series.

4. Supercomputer: They are the fastest and most expensive machines. They have high processing speed compared to other computers. They have also multiprocessing technique. One of the ways in which supercomputers are built is by interconnecting hundreds of microprocessors. Supercomputers are mainly being used for whether forecasting, biomedical research, remote sensing, aircraft design and other areas of science and technology. Examples of supercomputers are CRAY YMP, CRAY2, NEC SX-3, CRAY XMP and PARAM from India.

In-text questions 3

Into how many generations the evolution of computer is divided?
What is VLSIC?
The personal computer that you see today is in which generation of computer?

What you have learnt

In this lesson we have discussed about the major characteristics of computer. The speed, accuracy, memory and versatility are some of the features associated with a computer. But the computer that we see to
day has not developed over night. It has taken centuries of human effort to see the computer in its present form today. There are five generations of computer. Over these generations the physical size of computer has decreased, but on the other hand the processing speed of computer has improved tremendously. We also discussed about the varieties of computers available today.

Terminal questions

1. Why is computer known as data processor?

2. Explain in brief the various generations in computer technology?

3. Write a short note on Fifth Generation of computer. What makes it different from Fourth generation computer?

4. Why did the size of computer get reduced in third generation computer?

5. Give short notes on the following:

Versatility
Storage
Slide Rule
Babbage’s Analytical Engine

6. Distinguish between Microcomputer and Mainframe computer.

Feedback to in-text questions

In-text questions 1

A computer is an electronic device, which is used to accept, store, retrieve and process the data. It is called as data processor because it is mainly used for processing data for producing meaningful information.
The characteristics of computer are speed, accuracy, diligence, versatility and storage.

In-text questions 2

Analytical engine, 1823.
Charles Babbage

In-text questions 3

Five generations
Very Large Scale Integrated Circuits
Fourth Generation

Terminal questions

Explain various types of computers.
Explain in brief the various generations in computer technology.
Write a short note on Fifth Generation of computer. What makes it different from Fourth Generation computer?
Why did the size of computer get reduced in Third Generation computer?

In-text questions 4

1. State True or False

Word processor is Software Package that enables you to create, edit, print and save document .
WordStar is a popular Word processor.
Changing the size of the margins cannot reformat complete document or part of the text.
Word has the facility of Macros.
Word does not allow the user to mix the graphical pictures with text.

In text questions 5

1. Choose the best answer.

1. While working in Microsoft Word you have to work with

Mouse only
Keyboard only
Both mouse and keyboard

2. In Ms- Word every command is available in

Print
Letter
Icons

3. You can go inside Microsoft Word by the following way

Take the mouse pointer to start button on the task bar and click the left mouse button.
Take the mouse pointer to start button and click the right mouse button.
Move the mouse pointer on the screen.

4. State True or False

The title bar displays the name of the currently active word document
The most commonly tool bars are the Formatting tool bar and the Standard tool bar.
The Tool bar allows you to format the vertical alignment of text.
The Scroll bar helps you to scroll the content or body of document.
The work space is the area in the document window where you enter/type the text.

In-text question 6

1. State True or False

Using View option you can perform editing functions such as cut, copy, paste, find and replace etc.
Using the Edit option you can switch over from Normal mode to Out line mode.
Using Insert menu you can insert various objects such as page numbers, footnotes, picture frames etc.
Using Tools menu you can access to various utilities of word such as spell check, macros and mail merge etc.
Window menu allows you to work with two documents simultaneously.

Introduction To Computer

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

- Characteristics/Features of Computer

Speed
Accuracy
Reliability
Storage Capacity
Word Length
Diligence
Versatile
Automatic
Electronic
Non-intelligent

- Application Areas of Computer

Education
Communication
Business
Transportation
Banking
Helth
Security
Industry
Scientific Research
Entertainment
Weather Forecasting
Desktop Publishing
Designing
Satellite Controlling

- Aviation

Capabilities & Limitations of Computer
Advantages & disadvantages of Computer
History of Computer

- Mechanical Age

Abacus
Stepped Reckoner (Leibniz Calculator)
Napier Bone
Difference Engine
Slide Rule
Analytical Engine
Pascaline
Tabulating Machine

- Electro Mechanical Age

MARK-I [Also known as ASCC (Automated Sequence Controlled Calculator)
MARK-II
ABC (Atanasoft Berry Computer)

- Electric Age

ENIAC
EDAC
EDVAC
UNIVAC

Some Important Persons
o Joseph Jaquard
o Charles Babbage
o George Boole
o Herman Hollerith
o Lady Augusta Ada Lovelace

Input Devices

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Some of the input devices used in a computer are keyboard, mouse scanner, joystick, touch screen, touchpad, track ball, bar code reader, light pen, optical code reader (OCR), MICR, OMR, microphone, digital camera, webcam, card readers, digitizing tablets, etc.

Keyboard

Keyboard is the most basic input device. It is used for text input. It contains multiple keys. User can provide input by pressing the key. The different types of key found in keyboard are:

Alphanumeric keys (A-Z, 0-9)
Function keys (Ctrl, Alt, Caps lock, Enter, Tab, Shift)
Special function keys (F1, F2, F3,……..,F12)
Cursor movement keys (?, ?)
Punctuation keys (,, “” , ’’, ?, !)
Numeric pad
Multimedia keys

On the basis of keys, keyboard can be classified as

XT keyboard -83 keys
AT keyboard -101 keys
Enhanced keyboard -103 and more keys

A keyboard contains an electronic circuit known as keyboard encoder. This circuit detects the pressed key, generates its electronic signal and transmits towards CPU.
On the basis of connectivity, keyboard can be wire or wireless.

Mouse

Mouse is a most common pointing and selecting device. It is used in graphical user interface. Mouse contains buttons for providing inputs. User can provide inputs by moving the mouse and pressing the button. On the basis of buttons, mouse can be:

Two-buttoned mousse
Three-buttoned mouse

Usually, the left button of the mouse is for normal selection and the right button is used for special function and central button is used for scrolling a document.
On the basis of working mechanism and its architecture, mouse can be classified as:

Mechanical mouse
Opto-mechanical mouse
Optical mouse

Mechanical mouse contains a rubber ball and a pair of rotating wheels. When the mouse is moved on the table, the ball rotated which results in rotation of the wheels and generates electronic signal.
Optical mouse operates using reflection of light. It is easier to use but usually less reliable than mechanical mouse.
The opto-mechanical mouse contains both mechanical and electric component.

Track ball
Trackball is the modification of mechanical mouse. It contains rubber ball on its top. User can move the cursor by rotating the ball with finger. It also contains two buttons on the either sides similar to mouse. It was used in older laptops.

Track pad/Touch pad

Track pad is the modification of optical mouse, and touch pad is further modification making it touch sensitive. It contains a window with two buttons on the either sides. User can also provide left click option by tapping the window with the finger. It is mainly used in portable devices like laptops, notebook, palmtop, etc.

Joystick

Joystick is a hand held pointing device which is mainly used for playing games. It is used for controlling objects, their movement, direction and speed of movement. Modern joysticks handle can move in any direction. When the handle is moved, the electronic circuit in the base detects the movement and sends corresponding binary signals to CPU.

Light pen

Light pen is used for creating drawings, designs by directly touching the screen. It is mainly used by designers, architects, engineers, etc. it is used in monitor not having touch screen facility. It is a pen shaped structure containing photo sensitive tip which can capture light emitted from the monitor and mark the position on the monitor.

Touch screen

Touch screen is none of the common input device at present mainly for portable computers. User can provide inputs by directly touching the screen with the metallic pen (stylus), finger or any pointed object. Touch screen is developed by using either of the following technologies:
a) Pressure sensitive
b) Capacitive
c) Infrared

Scanner

Scanner digitizes hard copy or printed images which can be used in digital computers. Scanner copies the image and draws a new digital image in its memory similar to hard copy image.

OCR (Optical Character Reader)

OCR digitizes handwritten or printed text.
Printed text will have fewer errors than hand written. It directly converts hand written text into digital text which can be edited. OCR contains predefined format of all the characters. During digitizing process, it creates an image of the character and compares it with stored format to determine the character.

MICR

It stands for Magnetic Ink Character Reader. MICR is an OCR that can digitize text written or printed by using magnetic ink like iron oxide or barium ferrite. It is used in security systems and for processing cheque in bank.

OMR

It stands for Optical Mark Reader. It is used for answer sheet correction in multiple choice questions. With the use of OMR answer sheet correction will be faster and error free.

BCR

It stands for Bar Code Reader. Bar codes are the magnetic lines used for storing the information about the product like manufacturing date, expiry date, company name, etc. BCR is used to read the information stored in bar codes. Bar codes are also used in security system.

Microphone

It is an input device for sound. It captures sound wave, converts it into digital format and provides it to the CPU. Common mobile computing devices like PDA, smart phone contains microphone.

Digital camera, Web camera

Digital camera captures real time images and video and stores it in a digital format. The image captured by digital camera can be directly used in a digital camera.

Web camera is a digital camera used in internet. It usually captures low quality images so that it could be transmitted at a faster speed.

Card reader

It is used to read the information stored in cards like ATM card, Credit card, Smart card, etc.

Digitizing tablet

It is used to digitize large map or hardcopy images. It is also used to track the movements of living beings and capture them in digital format.

Operating system

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Operating system is an interface between computer and hardware and application software. Without OS no computer can be operated. Operating system is regarded as the heart of living being for a computer system.
In other words, OS is defined as a program or suit (support for) of programs that controls the entire operation of the computer, such as recognizing input from keyboard, sending output to the display screen keeping track of files and directories on the disk and controlling peripheral devices such as disk drives and printers.

Basic organization of operating system:

An Introduction To Windows 95

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Introduction to Windows-95

Windows 95 is the upgraded version of Windows 3.x series with lots of new features embedded into it. It is a complete paradigm shift from windows 3.x working environment.

It is the entry point to a 32-bit operating/computing environment with less set of hardware requirements. It has more compatibility with other software as compared to its previous version and provides easy installation. It also runs most of the Windows 3.x and Microsoft DOS programs. Windows 95 also provides flexibility to configure hardware, easy link to a network or setup a network, install and uninstall programs automatically. It also has lots of other useful features like easy Internet access, multitasking, and its most useful feature is long file names.

Objectives

At the end of this lesson you would be able to

Understand the difference between Windows 3.11 and Windows95.
Able to work on Windows95
Appreciate the uses of Long file name
Appreciate the new look and feel of Windows95.

Improved features of Windows 95

Graphical user interface:
As compared to Windows 3.x, Windows 95 provides user-friendlier interface to work on. Its improved graphical user interface makes learning and using Windows 95 more natural and easier for all types of users. It is more powerful, customizable and efficient.

Start button
Introduction of start button in Windows 95 made life much simpler while there is a need to access multiple programs. It is the gateway of accessing most of the functionality available in the computer loaded with Windows 95. Just click on the start button anytime to start any programs, open or find documents, change windows settings, get help, manage Files, maintain system, and much more.

Taskbar
As the name suggests, the Task bar provides information and access to the entire task that has been currently activated by Windows 95. Using this one can keep a track of what all programs have been activated and switched between them.

Windows explorer
Windows explorer is more or less acts as a File manager for Windows 95, but with lots of new features. It is more efficient, faster and user friendly as compared to File Manager of Windows 3.x.
Using explorer one can easily browse through all the drives and network resources available and manage files.

Right mouse button
Clicking on the right mouse button activates a pop-up menu in any programs so as to help in completing a task efficiently.

Long file names
As the Microsoft DOS convention follows, non-of the file used in DOS environment should be more than 8 characters of primary name and optional secondary name (extension) of three characters. However Windows 95 has broken this barrier. Windows 95 supports long file names, maximum of 255 characters. It also allowed space to be used in between file name. This helps to make files and folders (directory/subdirectory) easier to organize and find.

Shortcuts
As the name suggests, shortcuts are the shortest way to access programs, files and other resources in Windows 95. Instead of going through the structural process of accessing a program, one can create “shortcuts” to access them. It creates links for easy access to files, programs, folders, and more.

Multitasking
Multitasking allows the user to activate and accomplish more than one task at a time. For example, work on a document file in WORD programs, while copying file from other computer available in the network. With Windows 95, 32-bit computing environment, the user can do more than one task a time.

Easy internet access
One of the most useful and entirely new features is Windows 95 easy access to Internet. It provides built-in Internet functionality to setup link and access Internet with less amount of Hardware and Software requirement. It also provides connectivity software from Microsoft network (MSN), CompuServe, and America Online.

It also improves the efficiency of working on Internet with applications that support the latest Internet technologies, such as ActiveX, Java, and streaming audio and video.

Software Compatibility
Windows 95 provides complete backward compatibility. It is easily compatible with applications developed for Microsoft DOS and Windows 3.x environment. It also supports the latest 32-bit technology. Most of the latest software packages are now built on Windows 95 operating environment.

Great gaming platform
Windows 95 support rich graphics, high quality audio and video. It also requires all most no editing of Config.sys files so as to support these technologies. All this is possible because of Windows 95 compatibility with latest and hottest technologies like Plug and Play, AutoPlay, and built-in support for MIDI and digital and surrounds video.

Hardware compatibility
Windows 95 provides greater Hardware compatibility as compare to any other operating environment. It has flexibility of supporting hardware from different vendors. Its Plug and Play functionality allows to insert the hardware card into the computer and when the computer is turned on Windows 95 automatically recognizes and sets up the hardware.

Find utility
Find Utility of Windows 95 allows you to do searches by partial name, last modified date, or full text. In addition, you can save, rename, or view files from within the result pane, just like you can from Windows Explorer.

Help
Windows 95 provides online help to accomplish a task. If the user is not sure how to perform a task, Windows 95 Help will provide structured process how to accomplish the task. Simply right-click on any object in the user interface (icons) and you’ll get relevant descriptions about that object.

1. System requirements

CPU	Recommended 486/25 MHz-based system or more
Memory	Recommended a minimum of 8-MB memory (RAM).
Hard disk space	Available free hard disk space of 40-45 MB.
Display	VGA or higher-resolution display.
Operating system	Microsoft DOS
Peripheral/miscellaneous	Compatible pointing device

2. Windows desktop items

My computer	Provides direct access to local drives, printers, control panel, and the Dial-up network utility.
Network neighborhood	Access to shared resources on the machine and computers on local and wide area network.
Recycle bin	Provides drag and drop facilities, deletion of file from folders in the machine and provides a second chance to recover files deleted from the hard disk.
Inbox or Microsoft Outlook	Universal in-box for all mail sources including faxes, mail, exchange, and others.

Start button and task bar

Windows now features the Start button and Taskbar at the bottom of the screen. This bar contains the Start button. Using this button, a program can be quickly started or file can be searched for. Quick help on how to use windows can also be obtained from this task bar.

Click on the start to activate the pop-up menu so as to open a program, find a file or folders (directory or sub-directory), and change the settings for Windows95, Run a program or shut down the computer and also to get help on windows.

If you have opened more than one program or windows, you can switch between them. All the opened windows or program appears on the Start or the Task bar as a minimized icons. Click on the desired icon to open the designated program. Similarly if you don’t need a windows too frequently, click on the minimized button of the windows. This will send the activated window as small icon to the task bar.

1. Steps to start a program

Click on the Start button, and then point to Programs option.
Select the program you want to run. If the program you want is not on the menu, point to the folder that contains the program.
Click on the program icon or menu.

Once the selected program starts, a small icon appears on the taskbar. If you have opened more than one program, click on the required program icon on the taskbar to make it currently activated program.

If the desired program is not available on the program menu or one of its submenus, point to Find on the Start menu, and then click Files Or Folders where the program resides. You can also use the Find dialog box to locate the program file.

2. Steps to open a recently used document

Click on the start button
Select/point to Documents option.
Select the document you want to open, by clicking on it

Note:
All programs are not capable of adding files to Document menu. So if the desired document to be opened is not listed or available in Document Menu, click on the Start button, and then select the Find option. Select/click “files Or folders” option, and then use the Find dialog box to locate the file.

My computer

It allows looking at a glance to all the resource available on the machine such as floppy drive, CD-ROM drive, Hard Disk etc. If you have network drives mapped as local drives they will also show up here. Double clicking on a drive in the top level of my computer will open another window containing the main folders on the select drive. Double clicking on any of the folders in the drive window will open another window showing the contents of the folder.

Double clicking on either the control panel folder or the Printers folders in My Computer windows will activate the respective windows for Control panel or Printers. Using this you can manipulate the settings for your Computer or Printer the same way that you were accessing them from the start menu.

My Computer is the quickest way of accessing all the resources available on the computer. Even this can be used to copy, move, delete files among or between floppy and hard disk or network drives.

My Computer also provides the tools to change the settings of the available resources. Select the media such as floppy disk, hard disk drive you want to change the settings and right click on it. This will activate a Pop-Up menu. Now select the Properties option from the pop-up menu. This action will display the property windows with three options: General, Tools and Sharing. Using these three options you can change the properties of the selected media.

Windows explorer

As the name suggests, Windows Explorer let you explore the contents of your computer and do file management. It is the improved version of file Manager in Windows 3.1 or 3.11.

To activate Windows explorer, click on the start button on the task Bar and select programs option. This will activate another Pop-Up menu. Now select Windows Explorer option.

Windows Explorer displays on the left-hand side of the screen, all the folders on your computer in a hierarchical order. On the right hand side of the screen, it displays all the files and folders in each selected folder.

Windows Explorer is especially useful for copying and moving files. You can open the folder that contains the file you want to move or copy, and then drag it to the folder you want to put it in.

Steps to copy a file or folder

Go to My computer or Windows explorer
Select the file you want to copy by clicking on it.
Go to edit menu and select/click Copy option.
Open the folder or disk drive where you want to copy.
Again go to edit menu and select/click Paste option.

Steps to move a file or folder

Go to My computer or Windows explorer
Select the file you want to move by clicking on it.
Go to edit menu and select/click cut option.
Open the folder or disk drive where you want to move.
Again go to edit menu and select/click Paste option.

Steps to delete a file or folder

Go to My computer or Windows explorer
Select the file or folder you want to delete by clicking on it.
Go to file menu and select/click delete option.

Note:

Files or folder deleted are stored in the Recycle Bin until the Recycle Bin is emptied. Files or folders can also be deleted by dragging file or folder icons onto the Recycle Bin icon. If SHIFT key is pressed while dragging, the item will be deleted permanently from the computer without being stored in the Recycle Bin.
To select more than one file or folder to copy, while pressing the CTRL key, click the items you want to select.

Steps to copy a file to a floppy disk

Insert the disk in the floppy disk drive.
Go to My computer or Windows explorer
Select the file you want to copy, by clicking on the file.
Go to file menu, point to “send to” option, and then select the drive you want to copy the file to.

Steps to create a new folder

Go to My computer or Windows explorer; open the folder in which you want to create a new folder by double clicking on it.
Go to the file menu, point to New, and then click on the “folder” option.
The new folder appears with a temporary name.
Type a name for the new folder, and then press enter.

Steps to change the name of a file or folder

Go to My computer or Windows explorer
Click on the file or folder you want to rename.
Go to the file menu, and select/click “rename” option.
Type a new name for the file or Folder, and then press enter.

Note :
As Windows 95 supports long file name, a filename can be up to 255 characters, including spaces. However, it cannot contain any of the following characters:

/ : * ? ” < > |

Network neighborhood

A Network is a group of Computers connected to each other to share available resources such as storage and printers. Network neighborhood takes the ability of My Computer and extends them one step further, by giving you with the ability to view all of the Computers connected in workgroup or network, and see what drives or Printers may be available for use. If you double click on one of the Computers, any resources that Computer shares with others in the workgroup like- drives, directories or printers will be listed

When connected to a network, the Network Neighborhood icon appears on the desktop. To browse through the computers in the workgroup and the computers on the entire network, double click on the icon Network Neighborhood.

Recycle bin

The files deleted by you are put in the Recycle Bin, a holding place for files that are no longer needed. There you can also drag and drop files for quick deleting. They are, however, not actually removed from the hard disk until the user “empty” the recycle bin.

It is a safety feature, built in to protect you against the possibility of deleting something you should not have.

Find

Using Windows 95 it is easy to locate files and folders on the computer. One way is to browse through folders in My Computer. But if you want to find something quickly, you can use the find command on the start menu.

Click on the start button and select “find” option. Now select the option "files or folders". This will activate the find dialog box. In the find dialog box, type the name of the file or folder you are looking for, and then click find Now. You can also use wildcard character to find files

Work with programs

Windows 95 provides higher level of flexibility in terms of installing and removing programs.

To install a program from a floppy disk or CD-ROM
Select control Panel from the Settings option of Start Menu
Double Click on the add/remove programs icon.

Follow the instructions on your screen.

To install a program from a network

Click here to open the add/remove programs dialog box.
If the Install/Uninstall tab is selected, and your computer is already connected to a network, click Install button, and then click Next. Follow the instructions on your screen.

Note:
If you do not have a Network Install tab in the Add/Remove Programs dialog box, this feature has not been enabled on your computer, your network, or both. See your system administrator.

If you are not already connected to the shared folder you want to install from, you must connect to it by using My Computer or Windows Explorer, or type the path to it in the text box.

To remove a program from your computer

Select Control Panel from the Settings option of Start Menu
Double Click on the add/remove programs icon.
Follow the instructions on your screen.

Note:
Only programs that were designed for Windows 95 can be removed by using add/remove programs. For all other programs, check the program’s documentation to determine which files should be removed.

Microsoft-DOS windows

Windows 95 provides the flexibility of executing most of the DOS commands or DOS based program without going out of Windows 95 GUI. To use DOS prompt:

Click the start button, and then point to Programs.
Click/Select MS-DOS prompt.

Tips

To view the toolbar, click the MS-DOS icon in the title bar, and then click Toolbar.
To switch between a full screen and a window, press alt + enter.
To quit MS-DOS, click or type Exit at the command prompt.

Change windows settings

Windows 95 provides tools to change the look and feel of the desktop window. Using these tools you can change the desktop background, wallpaper and lots of other settings according to your choice.

To activate these tools, right click on the windows. This will display a menu now select the properties option.

You can also activate these tools from Control panel by selecting the display icon.

Desktop background

To change the background of the desktop

Right Click on the Desktop to view the Display properties.
In the Pattern or Wallpaper list, click the pattern or wallpaper you want to use.

Tips

To cover the entire screen with wallpaper image, click Tile.
To center a wallpaper image, click Center.
Patterns and wallpaper can be used simultaneously. However, you will not be able to see the pattern, if Title is selected.

Similarly all other option such as appearance, screen saver and settings can be used. Using the settings option, one can select the number of colors, pixel type and display adapter for the system.

Shut down the computer

Click the start button, click the shut down button, and then select the option Shut down the computer and click on the yes button.

Important

Do not turn off your computer until the “You can now safely turn off your computer” message appears.

In-text questions 1
Choose the best answer for the following questions.
1. Which of the following is introduced exclusively in Windows95?

Control panel
File manager
Start button
None of the above

2. What is the Windows 3.x series equivalent to Windows Explorer in Windows95?

Program manager
File manager
Print manager
None of the above

3. Answer whether the following statement is True (T) or False (F).

Windows 95 supports file name of 255 characters including space in between.
Windows 95 does not support Microsoft DOS based application.
Windows 95 is a application software.
In Windows 95 desktop icons can be created, but can not be deleted.

4. Fill in the blanks

Inbox in Windows 95 is used for ______________________.
GUI stands for ________________________.

What you have learnt

This lesson introduced you to one of the most popular and widely used GUI operating system in desktop environment. In the beginning it discussed what is GUI and its usefulness. It explained the new features of Windows95 and hardware requirement for installation. You also learned about various Windows 95 icons and their usability. Here we discussed how to do file management in Windows 95, and also we learned how to change look and feel of Windows 95 desktop according to user requirement.

Terminal questions

Briefly explain, how Windows95 is different from Windows 3.x series.
Explain what do you understand by multitasking?
What is the minimum hardware requirement for installing Windows95 software?
What is the purpose of recycle bin?
Explain the steps involved to shut down Windows95.

In-text questions 1

1. 3

2. 2

True
False
False
False

Getting e-mail
Graphical User Interface.