Bachelor of Information Technology Information Systems Technology IT
Bachelor of Information Technology Information Systems & Technology IT 1105 06. System Development 6. 2 Different approaches to Systems Development Part - 1 Prabhajinie Jayabaalasundaram MBCS, MBA
IT 1105 Information Systems and Technology Intended Learning Outcomes After completing this session you should be able to Identify different approaches to system development Identify the different phases of traditional System Development Life Cycle (SDLC)
IT 1105 Information Systems and Technology Last Lesson Information Systems Planning and Aligning Corporate and IS Goals Information Systems Planning Aligning Corporate and IS Goals Developing a Competitive Advantage Establishing Objectives for Systems Development Performance Objectives Cost Objectives
IT 1105 Information Systems and Technology Outline Systems Development Life Cycle – SLDC The Traditional Systems Development Life Cycle Prototyping
IT 1105 Information Systems and Technology Systems Development Life Cycle - SLDC The systems development process is also called a systems development life cycle (SDLC) because the activities associated with it are ongoing. As each system is built, the project has timelines and deadlines, until at last the system is installed and accepted. The life of the system continues as it is maintained and reviewed. If the system needs significant improvement beyond the scope of maintenance, if it needs to be replaced because of a new generation of technology or if the IS needs of the organization change significantly, a new project will be initiated and the cycle will start over.
IT 1105 Information Systems and Technology Systems Development Life Cycle - SLDC A key fact of systems development is that the later in the SDLC an error is detected, the more expensive it is to correct. One reason for the mounting costs is that if an error is found in a later phase of the SDLC, the previous phases must be reworked to some extent. Another reason is that the errors found late in the SDLC affect more people. Thus, experienced systems developers prefer an approach that will catch errors early in the project life cycle.
IT 1105 Information Systems and Technology Systems Development Life Cycle - SLDC Common systems development life cycles include • Traditional • Prototyping • Rapid application development (RAD) • Individual development. In addition, companies can outsource the systems development process. With some companies, these approaches are formalized and documented so that systems developers have a well-defined process to follow. Other companies use less formalized approaches.
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle Traditional systems development effort can range from a small project to a major undertaking. The steps of traditional systems development might vary from one company to the next. But most approaches have five common phases: • Investigation • Analysis • Design • Implementation • Maintenance and review
IT 1105 Information Systems and Technology The Traditional Systems Development Life In the systems investigation phase, potential problems and Cycle opportunities are identified and considered in light of the goals of the business. Systems investigation attempts to answer the questions "What is the problem, and is it worth solving? “ The primary result of this phase is a defined development project for which business problems or opportunity statements have been created, to which some organizational resources have been committed, and for which systems analysis is recommended.
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle Systems analysis attempts to answer the question "What must the information system do to solve the problem? “ This phase involves • studying existing systems and • work processes to identify strengths, weaknesses, and opportunities for improvement. The major outcome of systems analysis is a list of requirements and priorities.
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle Systems design seeks to answer the question "How will the information system do what it must do to obtain the solution? “ The primary result of this phase is a technical design that either describes the new system or describes how existing systems will be modified. The system design details system outputs, inputs, and user interfaces; specifies hardware, software, database, telecommunications, personnel and procedure components; and shows how these components are related.
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle Systems implementation involves creating or acquiring the various system components detailed in the systems design, assembling them, and placing the new or modified system into operation. An important task during this phase is to train the users. Systems implementation results in an installed, operational information system that meets the business needs for which it was developed. It can also involve phasing out or removing old systems, which can be difficult for existing users, especially when the systems are free.
IT 1105 Information Systems and Technology Question The following statements are based on the traditional software development life cycle. Identify the INCORRECT statement(s). (a) Systems analysis results in the design of databases and controls. (b) Systems maintenance includes some improvements to an operational system. (c) Systems design consists of defining the problem, identifying its causes and specifying the solution. (d) Systems analysis includes identifying the strengths, weaknesses, and opportunities for improvement. (e) Systems testing is the process of determining whether a program or system operates in the desired manner.
IT 1105 Information Systems and Technology Answer The following statements are based on the traditional software development life cycle. Identify the INCORRECT statement(s). (a) Systems analysis results in the design of databases and controls. (b) Systems maintenance includes some improvements to an operational system. (c) Systems design consists of defining the problem, identifying its causes and specifying the solution. (d) Systems analysis includes identifying the strengths, weaknesses, and opportunities for improvement. (e) Systems testing is the process of determining whether a program or system operates in the desired manner.
IT 1105 Information Systems and Technology Question Identify the correct statement(s) related to Information Systems Development. (a) The process of system development includes all aspects ranging from the problem to be solved to the implementation of solution. (b) Information system Planning transforms organizational goals outlined in the strategic plan into specific system development activities. (c) System Analysts are professionals who specialize in analyzing, designing and developing business systems. (d) System Developers are specialists who are responsible for modifying or developing programs according to user requirements. (e) Studying the existing system and identifying the strengths, weaknesses, opportunities and threats for improvement, are activities done during the problem definition phase
IT 1105 Information Systems and Technology Answer Identify the correct statement(s) related to Information Systems Development. (a) The process of system development includes all aspects ranging from the problem to be solved to the implementation of solution. (b) Information system Planning transforms organizational goals outlined in the strategic plan into specific system development activities. (c) System Analysts are professionals who specialize in analyzing, designing and developing business systems. (d) System Developers are specialists who are responsible for modifying or developing programs according to user requirements. (e) Studying the existing system and identifying the strengths, weaknesses, opportunities and threats for improvement, are activities done during the problem definition phase
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle The purpose of systems maintenance and review is to ensure that the system operates as intended and to modify the system so that it continues to meet changing business needs. As shown in Figure, a system under development moves from one phase of the traditional SDLC to the next.
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle Advantages Formal review at the end of each phase allows maximum management control This approach creates considerable system documentation. Disadvantages Users get a system that meets the needs as understood by the developers; this might not be what the users really needed Documentation is expensive and time consuming to create. It is also difficult to keep current.
IT 1105 Information Systems and Technology The Traditional Systems Development Life Cycle Advantages Disadvantages Formal documentation ensures Often, user needs go unstated or that system requirements can be are misunderstood. traced back to stated business needs It produces many intermediate products that can be reviewed to see whether they meet the users’ needs and conform to standards Users cannot easily review intermediate products and evaluate whether a particular product meets their business requirements
IT 1105 Information Systems and Technology Prototyping takes an iterative approach to the systems development process. During each iteration, requirements and alternative solutions to the problem are identified analysed, new solutions are designed and a portion of the system is implemented. Users are then encouraged to try the prototype and provide feedback. Prototyping begins with creating a preliminary model of a major subsystem or a scaled-down version of the entire system.
IT 1105 Information Systems and Technology Iteration 1 Iteration 2 Prototyping [Final] Iteration 3 Determine Requirements Analyse Alternatives Specify Design Implement Design User Review
IT 1105 Information Systems and Technology Prototyping For example, a prototype might show sample report formats and input screens. After they are developed and refined, the prototypical reports and input screens are used as models for the actual system, which can be developed using an end-user programming language such as Visual Basic. The first preliminary model is refined to form the second- and third-generation models, and so on, until the complete system is developed.
IT 1105 Information Systems and Technology Prototyping
IT 1105 Information Systems and Technology Prototyping Prototypes can be classified as operational or non-operational. An operational prototype is a prototype that works-accesses real data files, edits input data, makes necessary computations and comparisons, and produces real output. A non-operational prototype is a mock-up or model that includes output and input specifications and formats.
IT 1105 Information Systems and Technology Prototyping Advantages Users can try the system and provide constructive feedback during development. An operational prototype can be produced in weeks. Disadvantages Each iteration builds on the previous one. The final solution might be only incrementally better than the initial solution. Formal end-of-phase reviews might not occur. Thus, it is very difficult to contain the scope of the prototype, and the project never seems to end.
IT 1105 Information Systems and Technology Prototyping Advantages As solutions emerge, users become more positive about the process and the results. Prototyping enables early detection of errors and omissions. Disadvantages System documentation is often absent or incomplete because the primary focus is on development of the prototype System backup and recovery, performance, and security issues can be overlooked in the haste to develop a prototype.
IT 1105 Information Systems and Technology Question The following statements are based on implementation and maintenance stages of the traditional software development life cycle. (i) A system review that is caused by a problem with an existing system is called an event driven review. (ii) Unit testing is done by executing the system with large amounts of data. (iii) System review is the process of building the background to deploy a new system in an organisation. Which of the above statements is/are CORRECT? (a) Only (i) (b) Only (i) & (ii) (c) Only (i) & (iii) (d) Only (ii) & (iii) (e) All
IT 1105 Information Systems and Technology Answer The following statements are based on implementation and maintenance stages of the traditional software development life cycle. (i) A system review that is caused by a problem with an existing system is called an event driven review. (ii) Unit testing is done by executing the system with large amounts of data. (iii) System review is the process of building the background to deploy a new system in an organisation. Which of the above statements is/are CORRECT? (a) Only (i) (b) Only (i) & (ii) (c) Only (i) & (iii) (d) Only (ii) & (iii) (e) All
IT 1105 Information Systems and Technology Question Which of the following is a tool(s) show(s) the flow of data through a system and the processing performed on it? (a) ERD (b) DFD (c) RAD (d) JAD (e) CAD
IT 1105 Information Systems and Technology Answer Which of the following is a tool(s) show(s) the flow of data through a system and the processing performed on it? (a) ERD (b) DFD (c) RAD (d) JAD (e) CAD
IT 1105 Information Systems and Technology Question Which of the following statement/s is/are CORRECT about ‘prototyping’ approach to systems development? (a) The prototyping approach enables users to try the system and provide constructive feedback during development. (b) The prototyping approach creates considerable amount of system documentation. (c) During the ‘System Maintenance and Review’ phase/stage of prototyping, users are able to evaluate the system. (d) The prototyping approach enables early detection of errors. (e) Prototyping approach is useful, when the user requirements are not clear.
IT 1105 Information Systems and Technology Answer Which of the following statement/s is/are CORRECT about ‘prototyping’ approach to systems development? (a) The prototyping approach enables users to try the system and provide constructive feedback during development. (b) The prototyping approach creates considerable amount of system documentation. (c) During the ‘System Maintenance and Review’ phase/stage of prototyping, users are able to evaluate the system. (d) The prototyping approach enables early detection of errors. (e) Prototyping approach is useful, when the user requirements are not clear.
IT 1105 Information Systems and Technology Summary Systems Development Life Cycle – SLDC The Traditional Systems Development Life Cycle Prototyping
Bachelor of Information Technology Information Systems & Technology IT 1105 06. System Development 6. 2 Different approaches to Systems Development Part - 1 Prabhajinie Jayabaalasundaram MBCS, MBA
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