Information System and ISD Methodology

Hi, guys!!! How r your days going?? Hope it’s going well. I have passed an exciting week in this month that I will never forget in my life. Really, I’m enjoying my university life. Now, come to the main point..after being learned two topics, I have got one topic named Information System that my lecturer taught us very plainly.

Let me start with the definition of Information System. Information System is an integrated set of components for collecting, storing, and processing data and for delivering information, knowledge, and digital products. Business firms and other organizations rely on information systems to carry out and manage their operations, interact with their customers and suppliers, and compete in the marketplace. For instance, corporations use information systems to reach their potential customers with targeted messages over the web to process financial accounts, and to manage their human resources.

Types of Information System

Information Systems differ in their business needs and the information varies depending upon different levels in organization. Information System can be broadly categorized into following:

• Transaction processing system
• Management information system
• Decision support system

The information needs are different at different organizational levels. Accordingly the information can be categorized into three parts and they are Strategic Information, Managerial Information and operational Information.

Transaction processing system

It processes business transaction of the organization. Transaction can be any activity of the organization. For example, take a railway reservation system. Booking, canceling, etc are all transactions. Any query made to it is a transaction. This provides high speed and accurate processing of record keeping of basic operational processes and includes calculation, storage and retrieval. Transaction processing systems provide speed and accuracy, and can be programmed to follow routines functions of the organizations.

Management Information System

It assists lower management in problem solving and making decisions. They use the results of transaction processing and some other information also. An important element of MIS is Database. A Database is a non-redundant collection of interrelated data items that can be processed through application programs and available to many users.

Decision Support Systems

These systems assist higher management to make long term decisions. These type of systems handle unstructured or semi structured decisions. A decision is considered unstructured if there are no clear procedures for making the decision and if not all the factors to be considered in the decision can be readily identified in advance. A decision support system must be very flexible. The user should be able to produce customized reports by giving particular data and format specific to particular situations.

Information System Development Methodologies

Maddison et al. (1984) define ISD methodology as “a recommended collection of philosophies, phases, procedures, rules, techniques, tools, documentation, management and training for developers of information systems”.

There is a strong argument that the use of structured methodologies to support information system development (ISD) leads to fragment, highly specialized, low-direction jobs for system users. While deskilling is a work strategy which some managers may wish to pursue, many do not; structured methodologies are therefore inappropriate for many development projects. This paper is intended to simulate debate on process models to support alternative methodologies; it is presented in the context of current research and also on the basis of the author’s experience as a practitioner in the field of information system design.

The Waterfall Model Of System Development 

The elements of methodology are illustrated in above. These elements permit an individual to structure their understanding of appropriate solutions for a problem situation, according to their perspective and their previous experience of both the problem context and the methodology. A methodology affects the way in which individuals’ will perceive the context and tasks of development, with each component layer of the methodology acting as a filter to the next layer. Ultimately, the problem situation is perceived through the filters by successive elements of the methodology. A methodology affects the way in which individuals’ will perceive the context and tasks of development, with each component layer of the methodology acting as a filter to the next layer. Ultimately, the problem situation is perceived through the filters provided by successive elements of the methodology; these elements in turn are filtering through stakeholders’ perceptions of their utility and application.

Types of ISD methodologies

STARDIS

STARDIS is structured, analysis, design and implementation of information systems (STARDIS). It is developed by Gane and Sarson in 1979 and build on the work of stevens, Myers and Constantine. It is based on functional decomposition and the use of the data flow diagram. It is concerned with the section of an organization of program modules and interfaces. It is used when there is a backlog of systems waiting to be developed or insufficient resources available to develop all of the potential systems.

Information Engineering

Information Engineering is based on work of Finkelstein and James Martin Associates. It is a big method and it tends to be used by large organizations for strategic IS development projects. Information engineering is widely practiced. It is reasonably concise and attractive, consistent, and has a minimum of clutter. It is, however, a good important notation for attributes and unique identifiers.

Jackson Systems Development

JSD is an extension of program design methodology, Jackson Structured Programming (JSP). The main goal of JSD is to produce maintainable software, and its emphasis is on developing software. It does not deal with project selection, cost selection, requirements analysis, project management, user interface, and procedure design or user participation.

Prototyping

It is the process of building a model of a system. In terms of an information system, prototypes are employed to help system designers build an information system that institutive and easy to manipulate for end users. Prototyping is an iterative process that is part of the analysis phase of the systems development life cycle. During the requirements determination portion of the systems analysis phase, system analysts gather information about the organization’s current procedures and business processes related the proposed information system. In addition, they study the current information system, if there is one, and conduct user interviews and collect documentation. This helps the analysts develop an initial set of systems requirements.

System Development Life Cycle (SDLC)

SDLC is defined as the process 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 delivering the system as product to the user. It is a process of gradual refinement, meaning that it is done through several development phases. Each phase continues and refines what’s done in the previous phase.

Ohhmm,, I have finished writing..you guys are also tired reading it..so see u for the next topic…!!!