SOFTWARE MAINTENANCE
Abstract
A consequence of the widespread utilisation of computer based technology over the past few decades has been the emergence of vast, highly complex computer systems whose content and structure are increasingly resistant to modification and change. However fallible such legacy systems remain, many are
“mission-critical” whereby their failure may lead to the collapse of the business or industry in which they serve. In such cases, it is ultimately not possible to decommission the system in question. The present report investigates the nature of such systems and examines why legacy systems cause problems to Software Maintenance Managers? This report also provides a brief overview 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 terms of being an existing software application that is predominately within the maintenance phase of its lifecycle. Such systems are typically old and heavily modified from their original designs by years of maintenance, usually by many different people
[Moor00]. Although legacy systems are technically obsolete, having been written in assembly or early third generation languages such as COBAL Fortran and Coral, they generally represent considerable investment, and maintain significant value to their users [Benn95] [Brod95].
Legacy systems typically form the backbone of information flow within an organisation, and as such, are essential for the function of its business.
Failure in these systems is likely to have serious consequences hence why legacy software is often considered of a “mission critical nature” [Benn95] [Bisb99].
As can be expected, systems of this nature pose a number of problems to the users, and to the Software Maintenance Manager responsible for the upkeep of the system. Such problems range from the cost of maintenance to the utilisation of obsolete skills and technologies. However, several solutions have been proposed and documented in the literature in response to, and to minimise, these problems. Generally, they are classified under four categories: maintenance, re-development, wrapping and migration [Bisb99] [Lee97].
Therefore, the remainder of this report is ...
... middle of paper ...
...[Lien80] B.P. Lientz & B.E. Swanson, "Software Maintenance Management", Addison
- Wesley, 1980
[Merl95] E. Merlo, P-Y. Gagne, J.K. Girard, K Kontagiannis & P. Panangaden,
"Re-Engineering User Interfaces" IEEE Software Jan 1995, Vol 12 No 1
[Moor00] M.M. Moore, "Using MORPH", http://www.cis.gsu.edu/~mmoore/MORPH/dissertation/approach.html, 2000
[Nose90] J.T. Nosek, & P. Prashant "Software Maintenance Management: The Change in the Last 10 Years", Journal of Software Maintenance, 1999, Vol 2 No 3
[Press01] R.S. Pressnam, "Software Engineering: A Practitioner's Approach"
McGraw Hill, 2001
[Somm01] 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", Technical
Report CMU/SEI-97-TR-005, Carnegie Mellon University, June 1997
Let’s assume we have a pallet in manual check and we want to break it down to 80 totes. If this pallet has any problem such as not on shipment, no PO, no barcode then we will create 80 problems from just one problem and then problem become bigger when we inject 80 problems to the line 16 because everybody in 20 stations will pick one of the totes and turn on his blue and waiting for problem solver to fix the problem. This kind of problems definitely will slow down all associate at the line and they will put more pressure to problem solver and water spider while we need to stop creating problem from the manual check.
In the case of Tom and Fran, we have to know and identify not only the problems but also the resources that comprise it.
...adequate use when trying to explain complex ones (Salmon 1978: 179-180). Trigger notes that the fundamental flaw of the Systems theory was that it ‘was less useful in explaining change as it was in describing it (1989: 308).
and in this case this could occur due to a lack or even the failing of
with these issues. As a result, I would like to explore some of the gaps
all going up a level at the same time; there might be a few that fail
2) A problem that cannot be avoided but that can be solved,managed throuth the develoment of apropiate messages.
To trace the tracks to the start of mending this problem, we need to go
solved, and they will only continue to get worse. By ignoring these problems we can only
1.0 IntroductionIn this report I will be concentrating on the failure of software systems. To understand why software systems fail we need to understand what are software systems. Software systems are a type of information system. This is because a software system is basically a means for hardware to process information. Flynn’s definition of an information system is:"An information system provides procedures to record and make available information, concerning part of an organization, to assist organization-related activities."Humans have been processing information manually for thousands of years, but with the vast increase of demand for knowledge this century has meant that a new method of information processing has been needed. Software systems have provided a new means that is much faster and efficient.
need to be worked out. This page is not the end all, and contains no breakthroughs or answers. However,
If any of the goals is not achieved then there is flaw in the system and may result in bad outcomes.
However, there are a lot of weaknesses to outweigh the positives, which means that the model can be seriously questioned.
Computer software engineers use the basics and techniques of computer science, engineering, and mathematical analysis to the design, development, testing, and evaluation of the software and systems that enable computers to perform their many different tasks.
Software development follows a specific life cycle that starts with designing a solution to a problem and implementing it. Software testing is part of this software life cycle that involves verifying if each unit implemented meets the specifications of the design. Even with careful testing of hundreds or thousands of variables and code statements, users of software find bugs. “Software testing is arguably the least understood part of the development process” and is also a “time-consuming process that requires technical sophistication and proper planning” (Whittaker 71) It is important to comprehend this concept by understanding the different characteristics and aspects of software testing, and then to examine the techniques, procedures and tools used to apply this concept. This will enable the user to realize the problems faced by software testers and the importance of software testing.