Systems Development Lifecycle Analysis

Learning Objectives List the nine stages of the system life cycle Explain the system life cycle as an iterative process Discuss the information a system needs and how to collect it. Describe what is meant by identifying the problem.

System Development Life Cycle (SDLC) At some stage, most businesses will need a new computerised system to help them with their day to day tasks. This could be a system to keep track of all the students' names, addresses, telephone numbers and grades, or it could be a new system for an online bank to let customers open a high interest savings account. This could be a system to keep track of all the students' names, addresses, telephone numbers and grades, or it could be a new system for an online bank to let customers open a high interest savings account. No matter what the system might be, the organisation should use a System Development Life Cycle.

Identification Feasibility study Information Collection Analysis DesignDevelopment and Testing Implementation Maintenance Obsolescence

Termination Each stage of the SDLC can be terminated at any point if appropriate.

Why a new system? An end user or users (person, company or organisation) decides that a task would benefit from computerisation because it either: Cannot be solved by previously used methods. Cannot be solved by previously used methods.Or Similar problems seem to have been solved by computerisation elsewhere. Similar problems seem to have been solved by computerisation elsewhere. The manager or end user is the business or problem expert and knows what the problems are.

Systems Analyst A specialist who understands computers and computerised solutions to problems. Needed because even though the client hopefully understands the problem, they will probably not understand the consequences of using computers to try to solve the problem, or, indeed, whether such a solution is even possible. Needed because even though the client hopefully understands the problem, they will probably not understand the consequences of using computers to try to solve the problem, or, indeed, whether such a solution is even possible.

Analysis Phase The systems analyst must fully understand the nature of the problem and the business of the client.

Methods Of Information Collection 1.Interview Advantages: Interviewee can talk at length and so detail can be explored. Also, unlike a questionnaire, the direction of enquiries can be altered. Disadvantage: Very time consuming and so cannot interview many people. 2.Questionnaire Advantage: Find out the views of a large number of people very quickly. Disadvantage: Pre-determined questions and so people may find it difficult to put their point of view and opinions across. 3.Group meeting Advantage: Many people can discuss points and make their views known. Disadvantage: Not all the members of the group can give their opinions.

Methods Of Information Collection 4.Observation: Advantage: See first hand the system operating and may spot problems the actual users do not see. Disadvantages: People tend not to act in the way they normally do and only see a snapshot. 5.Document collection: Advantage: A clear indication of the data collection methods, input formats, uses and output formats. Disadvantages: Volume collected. Documentation often difficult for an outsider to understand, especially in isolation. Privacy issues.

After Data Collection All the information collected would need to be interpreted and analysed. Also different solution methods would need to considered.

Objectives & Discussions The manager’s requirements and the analyst’s understanding must match, otherwise the analyst will solve the wrong problem. Therefore, an agreed list of objectives must be created via thorough collaborative discussions.

Problem Definition / Requirements Specification / Expectations The most important part of the analysis because if it is not done correctly and the manager’s / end user’s requirements and the analyst’s understanding do not match, the wrong problem may be solved. Discussions between all the interested parties held, and then a list of objectives, requirements or necessary items written up. Discussions between all the interested parties held, and then a list of objectives, requirements or necessary items written up. Therefore, an agreed list of objectives must be created via thorough collaborative discussions. Therefore, an agreed list of objectives must be created via thorough collaborative discussions. The success or otherwise of the project depends on the completion of these objectives, requirements or items. The success or otherwise of the project depends on the completion of these objectives, requirements or items.

Plenary What are the stages of the system life cycle?

Identification Feasibility study Information Collection Analysis DesignDevelopment and Testing Implementation Maintenance Obsolescence

Plenary What is meant by the system life cycle being an iterative process? When one of the stages is completed the following stages may mean that the previous ones may need to be considered again. When one of the stages is completed the following stages may mean that the previous ones may need to be considered again.

Plenary What methods can be used to collect information about an information system?

Methods Of Information Collection 1.Interviews Advantage: Interviewee can talk at length. Disadvantage: Time consuming and so cannot interview many people. 2.Questionnaires Advantage: Find out the views of a large number of people very quickly. Disadvantage: Pre-determined questions and so people may find it difficult to put their point of view across. 3.Group meetings Advantage: A number of people can discuss points and make their views known. Disadvantage: Not all the members of the group can give their opinions.

Methods Of Information Collection 4.Observe the current system in action Advantage: Shows present system not just views which may be clouded. Disadvantages: People tend not to act in the way they normally do. Data and forms tend to be seen in isolation. 5.Collect printed documentation Advantage: A clear indication of the data used and the collection methods. Disadvantages: Volume collected. Data and forms tend to be seen in isolation.

Plenary What is meant by identifying the problem? Discussions between all the interested parties held, and then a list of objectives written up. Discussions between all the interested parties held, and then a list of objectives written up. The success or otherwise of the project depends on the completion of these objectives. The success or otherwise of the project depends on the completion of these objectives.