I-Concepts



An information system includes a computer program, application, or combination of hardware and software that is developed to solve a specific problem. The process of creating an information system is referred to as the systems development life cycle (SDLC).

The SDLC has five phases:

1. Feasibility and Planning (or Investigation): During the planning phase a feasibility study is conducted to determine whether a new system is a feasible solution. A project plan is developed and approval for the plan is obtained from management. Some authors refer to this phase as the investigation phase.

2. Analysis: The role of the analysis phase is to identify detailed requirements for the system. What business needs will the information system fill? What outputs will it need to produce? Who will use it? How many users will need to use it at the same time? What other systems will it share data with?

3. Design: Once the analysis phase has determined what the system will do, the design phase determines how it will do it. During the design phase, each portion of the new system is designed in detail, including the user interface, data structure, and the program design. The design phase often ends with a prototype — a working model of the system.

4. Implementation: The next phase is to actually create the components of the system. Testing should be an integral part of this phase, ensuring that each component works as it should and that the design plan is being followed. When development is complete, it's time to put the system in place. This can mean installing the software on end-users' computers or uploading a Web site to a Web server.

5. Maintenance: The work doesn't end with implementation. Ideally, the maintenance phase lasts until the system is no longer in use. The system must be monitored to ensure that it continues to work properly. Errors (or "bugs") may be found that need to be fixed, or new needs may arise which require modifications to the system. If the new needs cannot be met by the original system, the cycle starts over to design a significant modification to the system or to implement a new system.

1-Planning

The first phase of the systems development life cycle is the planning phase, sometimes called the investigation phase. During the planning phase the goals and objectives of the new system are clearly defined.

A feasibility study is conducted focusing on the technical, organizational, and economical aspects of the new system. The feasibility study should answer the question "Can the problem be solved?" Once the project is believed feasible, a project plan is developed. The project plan includes:

• Project team: This is a list of all the people who will participate in the project. This list should include managers, analysts, programmers, and every person who will be involved in developing the new system.

• A preliminary budget: Creating a budget at the beginning of the project can be a daunting task. It is important to try to gather accurate numbers in order to create realistic expectations.

• Step by step schedule: Each step of the development cycle should be detailed in a project timeline.

2-Analysis

The role of the analysis phase is to identify the business requirements for the information system. What needs will it fill? What outputs does it need to generate? Who will use it? How many users will need to use it at the same time? What is an appropriate schedule and budget? Considering all constraints, what is the best solution?

There are three crucial steps in the analysis phase:

1. Understand the old system

2. Identify how the old system can be improved

3. Develop specifications for the new system

It is important for the members of the development team to understand the organization —its people, activities, and current information systems. By having a clear understanding of the organization as a whole, the development team will recognize who will be affected by the new system, and how the new system will affect the people in the organization.

3-Design

Once a feasible solution has been selected, the design phase determines how the system will work. During the design phase, each portion of the new system is designed in detail, including:

• User interface

• Data structure

• Program design

Often, the design phase includes a detailed examination of how the system accomplishes the goals outlined in the analysis phase. The design phase ends with a prototype — a working model of the system.

4-Implementation

The next phase is to actually create the components of the system and to convert from the old system to the new system The implementation phase consists of the following steps:

• Acquire the appropriate hardware and software

• Develop software

• Test the system — Testing should be an integral part of this phase, ensuring that each component works as it should and that the design plan is being followed.

• Write documentation

• Training

• Conversion — When development is complete, it's time to put the system in place. There are four main conversion methods — parallel, pilot, phased, and plunge.

5-Maintenance

The work doesn't end with implementation. Ideally, the maintenance phase lasts until the system is no longer in use. During the maintenance phase, the system is monitored to ensure that it continues to work properly and meets expectations. If any errors (or "bugs") are found, they are fixed. Also, as requests from users come in, they are analyzed and the system is modified to accommodate any new needs which may arise.

If the new needs cannot be met by the original system, the cycle starts over to design a significant modification to the system or to implement a new system. The first step of the new Systems Development Life Cycle is the Planning phase, which focuses on the overall system changes that need to be made. The SDLC continues through each phase until a new system is in place that meets the needs of its users.

Case Study: System Development

1-What should the CEC systems development team do first?

2-What tasks should be completed during the analysis and design stages?

3-When the design stage is finished, what will the CEC team do?

4-Would prototyping or outsourcing make sense in this situation? Why or why not?

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