Software Engineering and The Software

Software Engineering Principles - Chapter 1

Objectives

At the end of this chapter students will be able to:

Explain Software
- Types of software
- Components of Software
- Features of software
- role of software.
Engineering Concepts
Software Engineering concepts

What is Software?

Any Computer program is Software
Computer program that provides functionality and performance.

Software is:

(1) instructions (computer programs)
That when executed provide desired features, functions, and performance
(2) Data Structures
That enable the programs to adequately manipulate information
(3) documentation
That describes the operation and use of the programs. So in simple words:

Instructions

Desired Functionality and Performance

Data Structures

Essential Component
Main Data
Program Logic and Design

Documents

User Manuals
Design Manuals

In nutshell, Software is more than just a program code.
A program is a set of instructions or a program is executable code which serve some computational objective. Software is considered to be set of executable code, associated with libraries and documentations. Software, when made for a specific requirement is called software product.

Types of Software

1. System Software

Any software designed for system use, it is not used by user to perform their tasks, but they are mandatory for running other applications.

Characteristics of System Software

Heavy interaction with Hardware
Multiple users
Concurrent Operations
Scheduling
Resource Sharing
Process Management
Complex Data Structures
Multiple external Interfaces

Main Function

Provide Interface to other applications
Hide the complexity from the higher level of applications

Examples:

Operating Systems
Device Drivers
Compilers
And File Management Utilities

Types of System Software Explained

A- Utility Programs

The programs which are used for protection, management or solving problems. In simple words they are helper programs, they come with operating system are we can install them separately examples, anti virus programs, disk drivers, backup software, compression programs , file viewers etc.

B- Translators

Translators are the programs which translates the Source code written any any language to computer language. There are three types of translators

Assembler: This translator translates the program written in Assembly Language
Interpreter: This is high level language translator, Interpreter translates the program written in any high level language line by line, and it is slower than Compiler
Compiler: This is also high level language translator , Compiler translates the whole program written in any high level language and is faster than Interpreter

C-Operating System

A set of programs which perform all the tasks, takes placed on your device like computer, or mobile. It host all applications running on that device. Operating System make interface between user and device, Examples of Operating Systems are: Windows Operating Systems, Disk Operating System (DOS),Linux Operating System, Unix Operating System, Mac Operating System, OS2, Android Operating System for Android Mobile Phones, IOS Operating System for Iphone Mobiles etc.

2- Real Time Software

Real time software is the program or set of programs which works in real time. These programs Monitor, Analyze and Control the real time events.
Components of Real Time Software

Input Data
Analyze the Data
Take appropriate action

Examples of Real Time Software

Radar Software
Air Traffic Control System
Food Control System
Sonar

3- Business Software

The programs which are used to perform business related functions, like payroll system, inventory management system, sales analysis system

4- Scientific and Engineering Software

Used for solving scientific problems
Examples:

Mat lab
Auto-cad
Mathematical

5- Embedded Software

Resides in Read only Memory (ROM)
Examples:

Mobile Software
BIOS

6- Personal Computer Software

Word Processing
Spread Sheet
Multi Media Software
Database Applications

7- Web Based Software

Web pages
Websites

What is Engineering?

Engineering is all about developing products like Vehicles , Motors, Computers robots etc using well defined , scientific methods and principles. if engineering is used for machines it is called mechanical engineering, if engineering is used for electrical devices it is called electrical engineering and similarly if engineering is used for making software it is said to be software engineering.
Engineering can also be defined as the application of scientific knowledge to solve the problems of real world.

What is Software Engineering

It is an engineering branch which is associated with constructing software product using well defined scientific methods, procedures and principles. The outcome of the software engineering is an reliable and efficient software product.
IEEE defines Software Engineering as:

The application of a systematic, disciplined, quantifiable approach to the development, operation and maintenance of software; that is, the application of engineering to software.
The study of approaches as in the above statement.
In brief according to IEEE:
Software Engineering is applying the principals of engineering to the development of software systems.

Some other definitions of software engineering are:

1. It is the application of engineering to the development of software product in a systematic method.

2. The systematic application of the technological and scientific experience, methods and knowledge to the design , implementation , testing and documentation of software.