Software Maintenance Essay -- essays research papers

SOFTWARE MAINTENANCEAbstractA consequence of the widespread utilisation of computer based technology overthe past few decades has been the branch of vast, highly complex computer outlines whose content and structure ar increasingly resistant to modificationand change. However fallible such legacy systems remain, many armission-critical whereby their failure may lead to the collapse of thebusiness or industry in which they serve. In such cases, it is ultimately notpossible to decommission the system in question. The present reportinvestigates the nature of such systems and examines why legacy systems causeproblems to Software Maintenance Managers? This report also provides a briefoverview as to how such problems can be minimised and controlled.Keywords Legacy systems, legacy system migration, mission critical systems,re-engineering, software wrapping, software evolution.1. Introduction The literature describes legacy systems in wrong of being an existingsoftware application that is predominately within the maintenance phase of itslifecycle. Such systems are typically old and heavily modified from theiroriginal designs by years of maintenance, usually by many different peopleMoor00. Although legacy systems are technically obsolete, having been writtenin assembly or early trinity generation languages such as COBAL Fortran and Coral,they generally represent considerable investment, and maintain significant valueto their users Benn95 Brod95. Legacy systems typically form the backbone of information come within anorganisation, and as such, are essential for the function of its business. Failure in these systems is likely to have serious consequences hence why legacysoftware is a good deal considered of a mission critical nature Benn95 Bisb99. As can be expected, systems of this nature pose a number of problems to theusers, and to the Software Maintenance Manager accountable for the upkeep of thesystem. Such problems range from the cost of maintenance to the utilisation ofobsolete skills and technologies. However, several solutions have been proposedand documented in the literature in response to, and to minimise, theseproblems. Generally, they are classified under four categories maintenance,re-development, wrapping and migration Bisb99 Lee97. Therefore, the remainder of this report is ... ...Lien80          B.P. Lientz & B.E. Swanson, "Software Maintenance Management", Addison- Wesley, 1980Merl95     E. Merlo, P-Y. Gagne, J.K. Girard, K Kontagiannis & P. Panangaden,"Re-Engineering User Interfaces" IEEE Software Jan 1995, Vol 12 No 1Moor00     M.M. Moore, "Using MORPH",http//www.cis.gsu.edu/mmoore/MORPH/dissertation/approach.html, 2000Nose90     J.T. Nosek, & P. Prashant "Software Maintenance Management The Changein the Last 10 historic period", Journal of Software Maintenance, 1999, Vol 2 No 3P ress01     R.S. Pressnam, "Software Engineering A Practitioners Approach"McGraw Hill, 2001Somm01     Sommerville, "Software Engineering", Addison - Wesley, 2001.Weid97     N. Weiderman, L. Northrop, D.Smith, S.Tilley & K. Wallnau,"Implications of Distributed Object Technology for Re-engineering", goodReport CMU/SEI-97-TR-005, Carnegie Mellon University, June 1997