Software engineering is the study and application of engineering to the design, development, and maintenance of software.

1. Ashek Mahmud Khan
Software Engineering
Software engineering: Software engineering is the study and application of engineering to the design,
development, and maintenance of software.
Define the characteristics of Software:
(i) Software is logical rather than a physical system elements.
(ii) Software doesn’t wear out.
(iii) Software continues to be custom built.
(iv) Software is developed or engineered; it is not manufactured in the classical sense.
What is 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 software contrasts with computer hardware, which is the
physical component of computers.
Or, Computer software is a program that tells a computer what to do. These instructions might be internal
commands, such as updating the system clock, or a response to external input received from the keyboard or
mouse. Though there are many different types of software made both with open source and proprietary
standards, the programming mostly comes down to a few basic rules.
Or, Software is Instructions (Computer Programs) that when executed provided desired function and
performance.
Classification of Software:
- System Software
- Application Software
- Engineering/ Scientific software
- Embedded software
- Product line software
- Web application
- Artificial intelligence software
- Ubiquitous software
- Net sourcing, The “new economy”.
- Legacy software
System Software: System software (systems software) is computer software designed to operate and
control the computer hardware and to provide a platform for running application software. System software
can be separated into two different categories, operating systems and utility software.
Example:
1) Microsoft Windows
2) Linux
3) Unix
4) Mac OSX

2. Ashek Mahmud Khan
5) DOS
6) BIOS Software
7) HD Sector Boot Software
8) Device Driver Software i.e Graphics Driver etc
Application Software: Application software is a set of one or more programs designed to carry out
operations for a specific application. Application software cannot run on itself but is dependent on system
software to execute. Examples of application software include MS Word, MS Excel, a console game, a
library management system, a spreadsheet system etc.
Embedded software: Embedded software is computer software, written to control machines or devices that
are not typically thought of as computers. It is typically specialized for the particular hardware that it runs on
and has time and memory constraints.
Scientific and engineering software: Scientific software is typically used to solve differential equations.
(Differential equations are used to describe continuous actions or processes that depend on some other
factors.) Although some differential equations have relatively simple mathematical solutions, exact solutions
of many differential equations are very difficult to obtain.
Artificial intelligence (AI): Artificial intelligence (AI) is the intelligence exhibited by machines or software.
It is an academic field of study which generally studies the goal of emulating human-like intelligence.
Example computer players, expert systems, robots, checking systems in some cases etc.
Product line Software: Software product lines, or software product line development, refers to software
engineering methods, tools and techniques for creating a collection of similar software systems from a shared
set of software assets using a common means of production.
Web Application Software: A web application or web app is any software that runs in a web browser. It is
created in a browser-supported programming language (such as the combination of JavaScript, HTML and
CSS) and relies on a web browser to render the application.