JSE_V2_N2_RP4 K. Vijayalakshmi N. Ramaraj Journal on Software Engineering 2230 – 7168 2 2 77 88 FMEA, Software reliability, Real time systems, Automation systems Nowadays more automation systems are coming with advanced technologies for various applications. An automation system consists of software and hardware components to achieve the good quality products and processes. In automation system, software and hardware quality has a continuously increasing impact on system reliability. The reliability defines as “the ability of a system or component to perform its required functions under stated conditions for a specified period of time”. If the software is inaccurate and less reliability means the system performance will poor and influenced greatly. If the hardware reliability is less, the system will meet the failures very often and leads the increase of maintenance cost. So the reliability estimation and improvement of software and hardware is an important task to improve the quality of automation systems. But, this paper aim is to identify and analyze the most important mode which is very crucial in the software based automation system. Prioritization of the critical mode is identified using Failure Mode and Effect Analysis (FMEA) according to its Risk Priority Number (RPN) and then the reliability of particular mode is identified. The reliability estimation will also help to identify the performance of the software based systems. A new direction in defect management system is proposed to improve the reliability of real time system. October - December 2007 Copyright © 2007 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=671