INFORMATION SYSTEMS

Information Systems Development Methodologies

Information Systems Development Methodologies

Introduction

The development of an information system is a complex and a high value process which comprises of different interrelated and steps and procedures, or phases. There are different types of methodologies available for designing and developing an information system. Different types of information systems development methodologies are used in different scenarios. The use of these methodologies depends on the tangible requirements of the system. There are different strategies available for the data processing.

There are two main categories of the information systems: centralised information system, and distributed information system. Distributed information system is usually preferred over centralised information system by the most of the Information System professionals. The centralised information system comprises of the processing of data and the retrieving of information through a centralised machine (usually called a server). In a distributed information system, the entire data, information, and applications is distributed over the remote computers.

Discussion

Different methodologies for designing information systems are discussed in this paper so that we can better understand the nature of methodologies. Different methodologies are suitable for different applications, a cluster of applications, or an organization. The decision for the selection of methodologies is made on the basis of type, costs and budgets, size of the information system, and target purpose of the information system. All the methodologies have certain common features such as user participation, abstraction, and diagrammatic modeling methods (Avison, D.E., 1990, pp. 45).

Abstraction comprises of simplifying an area by focusing on specific aspects of the system, neglecting others. The abstraction of a system, development approach produces a logical view of the system. It consists of 3-schema architecture. The 3-schema architecture comprises of conceptual model, external design, and internal design.

The diagrammatic modeling techniques follow on from the concept of abstraction. The diagrammatic modeling is focused on Processes, Data, and Events.

The user involvement in the process of information systems development means that the users are aware of the needs and requirements of the business area (Avison, D. E., 1997, pp. 71).

Traditional Systems Life Cycle

The very first methodology for designing and developing the information systems was the Traditional Systems Life Cycle. This traditional method is still employed for developing the complex, medium/large scale systems. Using the Traditional Systems Life Cycle, the system development process is divided into six prescribed phases that should be successively achieved with a precise division of factions between IS specialists and end-users. The deliverables of the phases of systems life cycle include: project definition, project scope, systems study, system design specifications, designing, programming, installation, and post-implementation.

Disadvantages of the Life Cycle Approach

The life cycle approach is very resource intensive. A great quantity of time and money required information gathering and planning documents, may take a long time till a system is ultimately implemented, because of change in the system may become outdated while it is still in the development process. It is nonflexible and restrains change. The life cycle is not suitable for decision-oriented applications. The life cycle approach does not permit for alterations and ...