Introduction to Information Systems Development
CHAPTER 2: INTRODUCTION TO INFORMATION SYSTEMS DEVELOPMENT
2.1 System Development
A lot of experience has been gained and tools, techniques and methods developed for analysis and development of systems. There are good systems and bad systems defined by their quality. Quality is a relative term that normally refers to the expectations of the customer and standards defined by an organization.
A methodical approach to software development produces faster results, efficient programs and better quality product. This suggests good project management that will plan, and control the team, cost, time and quality of the product.
System development has been done using:
- Adhoc method:
Quick and dirty, ‘smart programmer’ but not maintainable.
- Systematic approach:
To create a good and effective system.
Adhoc method
The adhoc method is sometimes called the “smart programmer”, who creates an application as required within a short time. However, there is no systematic method or planning and does not have proper documentation. It gives a program that is difficult to debug, difficult to maintain and cannot be corrected by other people. The end result is that the software is abandoned and created again. System development should be done by a team using specific methods that are understood and corrections can be done using the standard documentation.
Systematic
Systematic methods use well known methods and techniques with proper documentation in order to ensure the quality of the software product. They make use of project management to control the project time, budget and quality.
Some of the limitation/drawbacks of using unstructured methods are:
- Investment capital:
Normally much more than expected. If not properly set may be abandoned half way or if completed may not be used at all.
- Time scale:
Normally overshoots beyond the expected time thereby increasing the cost of project.
- Expected benefits not realized/achieved:
Functions that do not address the expected needs of users especially if there was no adequate consultation and agreement with the users.
- Installation setbacks:
The software does not work as expected due to many errors and takes long to correct.
- Maintenance:
Changes in the software to improve or add other functions may have high costs if the design was not properly tested.
The problems associated with bad project planning and control may lead to the project being abandoned after using a lot of resources. A good project strategy is to include users in the development cycle and used systematic methods that will manage the project as planned within the constraints of budget, time and resources.
2.2 Software development approaches
Methods used in software development may be categorized into several broad approaches sometimes referred to as methodologies.
A methodology may be described as a set of methods or a paradigm used in systems analysis and design, and which have similar characteristics in different systems.
Some of the common methodologies or approaches are:
- Structured methods:
Are process and data oriented models where the process is assumed to be stable. They offer a range of techniques and tools to develop the new system within a given framework. They emphasize more on processing rather than data. They have defined an overall structure which ensure consistent and completeness of the project.
- Information Engineering:
Are data centered models. Data is regarded as a resource in an organization. It adopts a strategic approach by using an organization wide corporate data models and in integrated approach t development of individual systems.
- Soft systems:
Unlike the first two, which may be well-structured and defined this approach assumes that the problem is normally ill-defined and considers both the social aspects and technical aspects. The methods require more user participation especially in the analysis stage. The methods use techniques such as of rich pictures to enhance understanding between user and analyst, which was introduced by Peter Checkland.