Thu 28 March 2024
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Systems Development Life Cycle

In the early years of business computing information system development was a disorganized process. It frequently produced discouraging results. Systems were normally delivered late, went over their budgets, and did not provide the expected services. The systems development life cycle (SDLC) approach was developed to improve the quality of information systems. By encouraging an organized approach to problem-solving. SDLS can produce better information systems.

 

Phases of SDLC

The following are five phases of SDLC. Each phase is dealing with a key issue and produces a result called deliverables. The result of one phase becomes the input for the next phase.

The five phases of the system development life cycle are as follows:

Identifying the Problem and Opportunities

This phase deals with the following questions:

  1. What is the problem?
  2. What are the alternative solutions?
  3. How much will the solution cost?
  4. Deliverable: A project proposal.

 

Analyzing and Documenting Existing System

This phase deals with the following questions:

  1. What does the existing system do?
  2. What do users need?
  3. What should the new system do?
  4. Deliverable: requirements statement.

 

Designing the System

This phase deals with the following question:

  1. How will the new system work?
  2. Deliverable: Detailed specification of program design.

Implementing the System

This phase deals with the following question:

  1. Does the system do what the programmer and unis believe it should do?
  2. Deliverable: Finished and tested information system.

Supporting the System

  1. How can we best train users?
  2. How can we make this system easier to use and more efficient?
  3. Deliverable: Post-implementation reviews.

There are several different versions of the systems development life cycle. Some versions identify more phases than others and use different names for individual phases.

 

The Waterfall Model

The systems development life cycle is a step-by-step process. Sometimes, problems occur at a later stage due to the work performed at an earlier stage. For example, in the systems analysis phase, the team may discover that the problem has not been formulated correctly. The waterfall model provides a way in the model for correction. It enables the analyst to return to a previous phase to make a correction. It is the most-widely used way to implement the systems development life cycle.

 

Phase 1 — Identifying the Problems & Opportunities

In phase 1, an organization recognizes the need for an information system. It defines the problem, identifies opportunities for change, and assesses the project’s feasibility. It mulls in a project proposal submitted to senior management. If this phase is performed well, it m that the right information system will be developed.

 

Recognizing Need for the System

New information systems are developed when there are deficiencies. Different types of problems are as follows:

  1. Performance problems such as slow response time
  2. Information quality problems such as out of date, inaccurate
  3. Economic problems such as system cost too much to operate
  4. Security problem such as too easy to break-in
  5. Efficiency problem such as wastes time generates too much paper
  6. Service problems such as difficult to use force people to do things awkwardly.

Even if the current system has no serious deficiencies, it may still be replaced if a redesigned system can generate new business opportunities.

A formal request is made to initiate a project. The request can be made to a committee that consists of representatives from senior management, information systems personnel, users, and middle managers. If a project is approved, the committee appoints a project team.

Goals for the first phase are:

  1. Determining the nature of the problem
  2. Examining alternative solutions
  3. Studying the project's feasibility
  4. Creating a proposal for the overall project.

 

Defining the Problem

A problem must be defined clearly before it is solved. It is not always very easy problems can be identified by different symptoms. A symptom is an unacceptable or undesirable result, and the problem is the underlying cause of the symptom. For example, people might complain about the computer take's long time to enter a transaction. Users may demand more powerful computers. But the slow response time is just a symptom. It may be due to the slow speed of network transmission. It is a waste of money to buy faster computers in this case.

Determining the exact problem is often a difficult task. This process should identify the features to be added in the information system to make it acceptable to users. Users must be involved in defining the problem but they normally cannot study the systems in a structured way. The system analyst talks to as many users as possible to discuss problems. Finally, the analyst recommends adding new features in an existing system or to develop a new system.

 

Identifying Opportunities

When the problem is identified and system requirements are specified, the project team looks at possible solutions. It includes internally-developed systems, off-the-shelf software, and externally-contracted solutions called announcing.

 

Developing a Plan

The project leader formulates a project plan after an appropriate solution has been identified. the plan identifies the project‘s goal and scope. It specifies all the activities that must be completed for the success of the project. The plan specifies the estimated time and cost for each activity. The plan also identifies activities that must be completed before new ones can begin. It indicates which activities can occur side-by-side.

Project plans are often graphically summarized by the Gantt chart. It is a type of bar chart that shows how the activities are performed over time. Project management software such as Microsoft Project provides an excellent means of developing and modifying project plans.


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