Computer Software

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence UNIT-III

COMPUTER SOFTWARE

Contents

Definition of Computer Software Classification of Computer Software

Difference between System and Application Software

Examples for System Software

• BIOS (Basic Input Output System) • Device Driver Software

• Operating System • Utility Software’s

• Compiler, Interpreter, Linker and Loader

o Difference between Compiler and Interpreter Examples for Application Software

• Productivity Software

o Microsoft Office Package MS Word

MS Excel

MS Power Point

MS Access

o Graphics Software

Paint programs

Design or draw programs

Presentation software

Animation Software

CAD

o Multimedia

o Database Management System

Firmware

Middleware

Techniques for acquiring a software

Design and implementation of correct, efficient, and maintainable programs

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence Computer Software

Computer software or simply software is any set of machine-readable instructions that directs a computer's processor to perform specific operations.

Computer system consists of two parts Hardware and Software

Computer hardware, which is constituted by the physical components of a computer.

Computer software, which tells the hardware what to do and how to do it.

Classification of computer software

Computer software can be broadly classified into two groups:

Application software

Application software is a software program which is designed to solve a particular problem for users. It satisfies the requirements of the end users.

Ex: Spreadsheets, database systems, desktop publishing systems, program development software, games, web browsers and so on.

System software

It represents programs that allow the hardware to run properly. It is transparent to the user and acts as an interface between the hardware of the computer and application software that the users need to run on the computer.

Examples: Operating System, BIOS, Device Drivers, Compiler, Interpreter etc…

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence Difference between System Software and Application Software

Subject Application Software System Software

Definition

Application software is computer

software designed to help the user

to perform specific tasks.

System software is computer software

designed to operate the computer hardware

and to provide a platform for running

application software.

Purpose It is specific purpose software. It is general-purpose software.

Classification •

Package Program,

• Customized Program

• Time Sharing,

• Resource Sharing,

• Client Server

• Batch Processing Operating

System

• Real time Operating System

• Multi-processing Operating System

• Multi-programming Operating

System

• Distributed Operating System

Environment

Application Software performs in a

environment which created by

System/Operating System

System Software Create his own

environment to run itself and run other

application.

Execution

Time It executes as and when required. It executes all the time in computer.

Essentiality Application is not essential for a computer.

System software is essential for a

computer

Number

The number of application

software is much more than system

software.

The number of system software is less than

application software.

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence System software

System software is computer software designed to operate the computer hardware and

to provide and maintain a platform for running the application software.

The following are the some of the examples for System Software

Computer BIOS (Basic Input Output System)

The computer basic input/output system (BIOS) provide the basic functionality to

operate and control the hardware connected to the computer.

When computer starts, The first function of the BIOS perform to initialize and identify system devices such as video display card, keyboard, mouse, hard disk, cd/DVD drive and other h/w.

The four main functions of a PC BIOS

POST(Power On Self Test) – When we switch on the system first the BIOS will checks all

the hardware components that are connected to the computer system and make sure no errors

exist before loading the operating system.

Bootstrap Loader - Locate the operating system. If a capable operating system is located, the

BIOS will load the OS related files from secondary storage device to the main memory of the

computer. This process is known as Booting and the corresponding program is known as

Bootstrap program.

Device Driver Software

Device drivers are system programs, which are responsible for proper functioning of

devices. Every device whether it is a printer, monitor, mouse or keyboard, has a driver

program associated with its proper functioning. A device driver acts like a translator between

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence

A driver is a program that allows the OS to communicate with hardware devices.

Every single piece of hardware inside and connected to your PC needs a driver for

communication.

Operating system

An operating system (OS) is system software that manages computer hardware and

software resources and provides common services for computer programs. The operating

system is an essential component of the system software in a computer system.

The operating system acts as an intermediary between programs and the computer

hardware. An operating system ensures that the system resources (CPU, memory, input/output

devices) are utilized efficiently.

For ex: there may be many service requests on a web server, where each user request

needs to be serviced. Similarly there may be many programs residing in the main memory.

Therefore, the system needs to be determine which programs are active and which need to

wait for some input/output Operation.

Utility software

Utility software is used to analyze, configure, optimize, and maintain the computer

system. Utility programs may be requested by application programs during their execution for

multiple purposes, some of which are as follows.

Disk defragmenters are used to detect computer files whose contents are broken

across several locations on the hard disk and move the fragments to one location In

order to increase efficiency.

Disk checkers are used to scan the contents of a hard disk to find files or areas that are

not correctly saved and eliminate them in order to make the hard drive operate more

efficiently.

Disk cleaner help the users to decide what to delete when their hard disk is full.

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Backup utilities are used to make a copy of the information stored on a disk, In case

disk failure occurs; backup utilities can be used to restore the entire disk.

Disk compression is used to enhance the capacity of a disk by compressing or

uncompressing the contents of the disk.

Antivirus utilities are used to scan for computer viruses.

Network utilities are used to analyze the computers network connectivity, configure

network settings, check data transfers or log events.

Command Line Interface (CLI) and Graphical User Interface (GUI) are used to

make changes to the operating system.

Compiler, interpreter, Linker, Loader

Compiler

A compiler is a special type of program that transforms the source code written in a

programming language into machine language, which uses only two digits-0 and 1 is known

as object code.if the source code contains different types of errors such as

1) Syntax errors-Errors (spelling mistakes and typing mistakes) that limit the compiler in

understanding a program are called syntax errors.

2) Logical errors-this occur when the program does not function accurately.

Interpreter

Like the compiler, interpreter translates the instructions into an intermediate form,

which it then executes.However, the major advantage of an interpreter is that need not go

through the compilation stage during which machine instructions are generated. This process

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence Linker

It is called link editor or binder,is a program that combines the object modules to form

an executable program. In case of large program, programmers prefer to break the code into

smaller modules (piece of code),as this simplifies the programming task.

Loader-A loader is a special type of program that copies programs from a storage device to

the main memory, where they can be executed. Most loaders are transparent to the users.

Difference between Compiler and Interpreter

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence Application software

Application software is a type of computer software that employs the capabilities of a

computer directly to perform a user-defined task

To better understand application software, for example the relationships of an electric

light bulb (an application) to an electric power generation plant (a system).

Typical examples of application software are

Word processors

Spread sheets

Media players

Education software

CAD(computer aided design),CAM(computer-aided manufacturing)

Data communication software

Statistical and operational research software.

Examples for Application Software

Productivity software

Productivity software (sometimes called personal productivity software or office

productivity software) is software dedicated to producing information, such

as documents, presentations, worksheets, databases, charts, graphs, digital paintings,

electronic music and digital video.

Let us now discuss different productivity software such as Microsoft office package;

graphics design software, multimedia software and database management software.

Microsoft office package

Microsoft office, introduced by Microsoft in 1989,is a suite of interrelated

applications for the Microsoft windows and Mac OS X operating systems.intially,it included

only Microsoft word,excel,and PowerPoint.

Microsoft word

A word processor is a software package that enables its users to create, edit, print, and

save documents for future retrieval and reference.

The key advantage of using a word processor is that it allows the users to make

changes to a document without retyping the entire document.

Users can create a variety of documents such as

Letters

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Resumes

Forms or any document that can be typed and printed.

Fig. Screenshot showing an ms word document

It enables users to do the following

Create documents and edit them later by adding more text, modifying the existing text and deleting or moving some part of it.

Change the size of margins to reformat the text in the document. Format documents by indenting or double spacing the text.

Change the font size and type. it also facilitates user to install new fonts. Insert page numbers, headers and footer.

Check the spellings and correct them automatically if they are incorrect. Display the word count and other statistics.

Format the text in a columnar style. Insert tables in the text.

Find and replace text.

Cut copy and paste portions of text from one location in the document to another. Insert graphics, pictures, and charts in the document.

Send the same letter to multiple recipients using the mail merge facility.

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence Provide online help for any option.

Microsoft Excel

In a spread sheet software application, the data is stored in rows and columns or cells,

which can be formatted in various fonts or colors. It is an example of spreadsheet Software

that is used to store, organize and manipulate data. The stored data can also be converted into

graphs for analysis.

Microsoft Excel includes a number of simple as well as complex formulas and

functions to calculate variables in the data. It is used in finance to automatically calculate

variables such as profit, loss, or expenditure.

It is widely used for the following applications

It is used to manage data records and name lists in a tabular fashion. Users can easily sort the list and filter it like a database tool.

It is excellent analytical tool widely used in business.

Pivot tables, one of its main features, can automatically sort, count, and total the data stored in one table or spreadsheet and create a second table displaying the

summarized data.

With these tables, users can conveniently analyse huge volumes of data.

It is widely used for managing inventory in companies. Using well designed forms, predefined functions and formulas and pivot tables.

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence Microsoft PowerPoint

It is used to create multimedia presentations and slide shows. Like Microsoft word, it

includes tools to format text and incorporate design templates.

When designing presentations using Microsoft power point,

users can add effects on slide transitions

add sound clips

images

animations

Video clips to make the presentation even more interesting for the target audience. It also offers printing options to facilitates the users to provide handouts and outlines

for audience as well as notes pages for the speaker to refer to during the presentation.

Fig. Screenshot showing an ms PowerPoint document

Microsoft Access

It is a database application used to store data that has been either obtained from its own interface or imported from other applications.

The stored data can then be used for reporting and analysis.

It can be use as the front-end with another application being used as the backend tables, such as Microsoft SQL server and non-Microsoft products such as oracle and

Sybase.

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Tables designed in this application support a variety of standard field types, indices and record locking and referential integrity features.

In addition, Microsoft access supports the use of macros to automate repitative tasks.

Fig. Screenshot showing an Ms Access document

Graphics software

Graphics software or image editing software is a program that allows users to create

and edit digital images and illustrations. Examples of such software include adobe Photoshop

illustrator, paint shop pro, and Microsoft paint.

Paint programs

These programs enable the users to create rough freehand drawings. The images are

stored as a bit maps and can easily be edited as and when required.

Illustration, design, or draw programs

These programs facilitate users with more advanced features than paint programs and

are particularly used for drawing curved lines.

Presentation software

This software helps users to create bar charts, pie charts, graphics, slide shows, and

reports.

Animation software

This software simulates a movement by displaying a sequence of images in a fraction

of a second.

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This software is used by architects and engineers to create architectural drawings,

product designs, landscaping plans, and engineering drawings.

Multimedia

Multimedia is a technology which stores data as text, photo, pictures, music, sounds, graphic, film and animation and gives the methods to collect and modify the data as desired.

Database Management software

DBMS (Database Management software) is a collection of programs that helps users

to store, edit, and extract data from a database (A database is a collection of information).

Today different types of DBMS, such as Microsoft Access, File maker, DB2, SQL server and oracle are available in the market.

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Firmware

Firmware is programming that's written to the read-only memory (ROM), EPROM of a computing device. Firmware, which is added at the time of manufacturing, it is used to run user programs on the device.

Firm ware is an integral part of electronic devices such as optical devices such as optical drives, routers, scanners, traffic lights, consumer appliances, digital watches, computers, computer peripherals, mobile phones and digital cameras.

Now application programs are available as firmware.

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Middleware

Middleware often sits between the operating system and application programs. Middleware is also known as plumbing because it connects two sides of an application and passes data between them.

Middleware can enable communication between two separate applications by providing messaging services.

Middleware is used in a client-server system. The middleware is a software layer acting as a connector between the client and server applications.

Client- it is a computer that sends a request a service to server. Server- it is a computer that provides the service to the client.

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B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer B Naresh, Lecturer in BVRICE, Dept., of Computer ScieScieScienceSciencencence Techniques of acquiring software

Pre-written software Customized software Public domain software

• Cost is less as many

customers share the

development and

maintenance cost.

• Users can buy and

start working

immediately.

• It is general purpose

software; hence, it

may not entirely

meet the user’s

requirements and

may not operate as

efficiently as

customized software.

• Changes can be

easily incorporated in the software

• Users can cordially

work with the

software

development team

to develop software

as per their

requirements.

• It is expensive to

maintain a software

development team

in small

organizations.

• Users have to wait

for the software to be ready. This may take several months.

• Mostly, it is free

and is available along with the source code.

• Users can

download\ it and start working immediately.

• Open-source

software is usually not thoroughly tested, so it may fail during operation.

• There is limited

support when compared to that available with customized and pre-written software.

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Design and implementation of correct, efficient, and maintainable programs

The design and development of correct, efficient, and maintainable programs depends on the approach adopted by the programmer to perform various activities that need to be carried out during the development process.

The entire program or software (collection of programs) development process is divided into a number of phases as shown in the below figure, where each phase performs a well-defined task.

The output of one phase provides the input for its subsequent phase. The phases in a software development process can be summarized as follows.

Software Development Life Cycle (SDLC) phases

There are various software development approaches defined and designed which are used/employed during development process of software, these approaches are also referred as

“Software Development Process Models” (e.g. Waterfall model, incremental model,

V-model, iterative model, etc.). Each process model follows a particular life cycle in order to ensure success in process of software development.

There are following six phases in every Software development life cycle model

1. Requirement gathering and analysis

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3. Implementation or coding

4. Testing

5. Deployment

6. Maintenance

1) Requirement gathering and analysis:

Business requirements are gathered in this phase. This phase is the main focus of the

project managers and stake holders. Meetings with managers, stake holders and users are held

in order to determine the requirements like;

Who is going to use the system?

How will they use the system?

What data should be input into the system?

What data should be output by the system?

These are general questions that get answered during a requirements gathering phase.

Finally, a Requirement Specification document is created which serves the purpose of

guideline for the next phase of the model.

2) Design: In this phase the system and software design is prepared from the requirement

specifications which were studied in the first phase. System Design helps in specifying

hardware and system requirements and also helps in defining overall system architecture. The

system design specifications serve as input for the next phase of the model.

3) Implementation / Coding: On receiving system design documents, the work is divided

in modules/units and actual coding is started. Since, in this phase the code is produced so it is

the main focus for the developer. This is the longest phase of the software development life

cycle.

4) Testing: After the code is developed it is tested against the requirements to make sure

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phase. During this phase unit testing, integration testing, system testing, acceptance testing

are done.

5) Deployment: After successful testing the product is delivered / deployed to the customer

for their use.

6) Maintenance: Once when the customers starts using the developed system then the actual

problems comes up and needs to be solved from time to time. In this process, the care is taken

for the developed product is known as maintenance.

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Important Questions

Define Computer Software and explain its classification (5M). Difference between System and Application Software (5M). Define System software give some examples (10 M). Explain BIOS and Device Driver Software’s (10M). Explain Compiler, Interpreter, Linker and Larder (10M).

Define Application software give some examples. (10M)

Explain firmware and middleware.(5M)

How to acquire computer software.(5M)