Predicates, Path Predicates and Achievable Paths in Software Testing

Fundamental Concepts of Computers:

A Computer is a system composed of two main components: Hardware and Software

Hardware:

The Hardware is the physical equipment. The Hardware of the Computer System consists of five parts:

 Input Devices

 Output Devices

 CPU

 Primary Storage and

 Auxiliary Storage Devices

Software:

The Software is a collection of programs that allow users to interact with the Hardware.

Computer Software:

Computer Software is divided into Two categories:

System Software and Application Software.

System Software:

The System Software manages the resources of a computer. It provides the interface between the hardware and the users. It provides a platform for maintaining and running other software's.

Example: Windows 95/98/Vista/7/8/10..

Application Software:

Application Software is a program designed to run under an operating system. Mostly , applications are designed for a very specific purpose.

Example: MS Word, Google Chrome, Windows media player, Skype etc....

System Software 

The System Software consists of programs that manage the hardware resources of a computer.

These programs are classified into three categories:

Operating System

System Development Software

System Support Software

Operating System

Operating System is a collection of software that manages the computer hardware resources and provides common services for computer programs

Example: DOS, WINDOWS XP, WINDOWS VISTA, UNIX/LINUX, MAC/OS etc.

System Development Software

The system development software includes:

Language translators-that convert programs into machine language for execution.

Example: Rational rose, UML diagram tools, design tools

System Support Software

The set of files and programs that help the computer to operate, control and extend the processing capabilities of the system is known as system support software. Generally, system support software is organized by computer manufactures and is written in low level language. It speeds up the operation of the drivers, services, system preferences and other configured files.

Example: System utilities, device drivers

Application Software
There are two types of Application Software:
General purpose Software and Application specific software

General Purpose Software is used for any general applications. It allows users to perform simple computer tasks. It purchased from a developer and can be used by any one.
Examples: Spreadsheets and word processing

Application Specific Software is designed to perform specific tasks.
Example: Image Processing, Mat lab, Accounting Software (like Tally, Busy, etc. ), Custom made software (like payroll, billing, reservations, etc.. ).