Information System Development Methodologies

 

ISD methodologies is a collection of procedures, techniques, tools and documentation aids which will help the systems developers in their efforts to implement a new information system.

TYPES OF ISD METHODOLOGIES

1. STRADIS
2. IE
3. Jackson System Development
4. Prototyping / Iterative Approach
5. Structured Approach ( SDLC )

1. STRADIS

 

STRADIS stands for Structured Analysis Design and Implementation of information Systems Development Methodology. This was developed by Chris Gane and Trish Sarson
in 1979. The structured approach to design was based on earlier work by Myers and Constantine (1974) which in turn were refined by Yourdon and Constantine (1978) and on the Jackson System Development.
Structured design is concerned with the selection and organization of modules and interfaces that would solve a pre-defined problem. STRADIS is still evolving and expanding to include the implementation stages. It is claimed that this methodology can be used for the development of both small and large systems as well as for non-automated systems – seen as a feasibility study.
The stages in STRADIS include the initial study, the detailed study, defining and designing alternative solutions and the physical design.

INFORMATION ENGINEERING ( IE )

This is a Top-down enterprise information systems development approach which forms a part of the strategy for the overall systems architecture. IE employs data models and process models for each business function or area, to formulate a basic framework of how an enterprise functions and how information technology can help it to function better.

JACKSON SYSTEM DEVELOPMENT

Jackson System Development (JSD) is a method of system development that covers the software life cycle either directly or, by providing a framework into which more specialized techniques can fit. Jackson System Development can start from the stage in a project when there is only a general statement of requirements. However, many projects that have used Jackson System Development actually started slightly later in the life cycle, doing the first steps largely from existing documents rather than directly with the users. The later steps of JSD produce the code of the final system. Jackson’s first method, Jackson Structured Programming (JSP), is used to produce the final code. The output of the earlier steps of JSD are a set of program design problems, the design of which is the subject matter of JSP. Maintenance is also addressed by reworking whichever of the earlier steps are appropriate.

From the technical point of view there are three major stages in Jackson System Development, each divided into steps and sub-steps. From a manager's point of view there are a number of ways of organizing this technical work. In this overview we first describe the three major technical stages and then discuss JSD project planning, the variation between plans, and the reasons for choosing one rather than another.

PROTOTYPING / ITERATIVE APPROACH

An easily modified and extensible model (representation, simulation or demonstration) of a planned software system, likely including its interface and input/output functionality.

STRUCTURED APPROACH (SDLC)

SDLC is defined as the process (as a whole) of developing system or software to meet certain requirements. It covers many activities starts from understanding why the system should be built, studying the project feasibility, analyzing problems, choosing the system design and architecture, implementing and testing it, up to delivering the system as product to the user.