Chapter 18 SDLC

 

• 1. What are the parts of a feasibility study?
  (i) A general description of a proposed system that will address the needs of sponsors.
  (ii) An indication of the costs and benefits of a proposed system
  (iii) Information about the resources needed to build the system
  (iv)A recommendation for the proposed sponsors of the project.
• 2. Each phase of an SDLC has deliverables.  What is the deliverable for the problem investigation phase and who would receive it?
  The system analyst needs a model of the system as it currently exists. He needs this so that he can understand the existing system. His model will show that he understands the system and this can be verified by walking through the models diagrams with users. The Model will include narrative information collected from users, data flow diagrams, an data dictionary and entity relationship diagrams that will model the data that is being captured by the current system.
• 3. What is project management?
  This is managing the resources needed to ensure that a project is finished on time and within budget and to the satisfaction of the end user. Project managers use tools such as PERT and Gantt charts for scheduling all the tasks that need to be completed. They are conscious of managing time, scope and resources for a project. To reduce time to complete a project the manager might decide to employ more workers which would increase costs. Or it might be that the scope of a project is changed so that it takes less time to complete the project. The project manager is always making decisions that balance the conflicting forces of time constraints, project scope and costs.
• 4. What software might a project manager use to help them?
  There are many Project Management software tools. Microsoft Project is a popular tool.
• 5. What is a pilot system?
  This is a system that has been implemented on a small scale to see if it will be suitable for implementation on a large scale at some future date.
• 6. What is parallel running?
  This is an implementation strategy whereby an existing information system continues running along side a new information system. The existing system is used as a control to verify that the new system is working correctly.
• 7. What is top down design?
  This is a system development technique whereby a large problem is broken down into small manageable units of work. Ideally each small part will have only one purpose (strong cohesion) and there will little or no effect on other units of work when one unit of work is changed (loose coupling). In reality top down design is only used for very simple applications. Bottom up design is an alternative that works fine for many types of problem. If the problem is well defined then a bottom up design is going to be more efficient.
• 8. What is system testing and how is it different from acceptance testing?
  System testing involves the designer doing the testing. He uses various techniques including black box and white box testing to ensure that every function and procedure works correctly. He uses integration testing to ensure that the system works correctly when all the parts are put together. Acceptance testing is user oriented. Users have to decide if the system meets or exceeds their expectations. Performance metrics set at the start of the project can be checked by the programmer. However, Beta testing whereby many users are given the opportunity to try and prove that a system does not work, is a form of acceptance testing.
• 9. What does file conversion mean?
  A new system may require that data, previously stored in some form in an old system, must be converted into a format that is suitable for a new system. This might mean changing the format of existing data files or it might mean keying in data from existing records in filing cabinets.
• 10. What is technical documentation?
  This is the information abut a system that is required so that maintenance of the system can take place. If we imagine what we might need to be able to change a big complex set of programs you will soon come to the conclusion that a lot of technical documentation is required and that managing this documentation is a big job all by itself. It is worth noting that 80% of the effort put into an information system is work completed AFTER implementation – when the system is supposed to be running. Therefore the technical documentation needed to make changes to software is extremely important.
• 11. What is user documentation?
  This is the documentation that is required by a user so that he can use the new information system that he has been provided with. It can be in the form of tutorials, manuals, E-books and web pages.
• 12. How would you evaluate a new system
  If a system has been built using a SDLC then at some stage the SCOPE of the project, the BUDGET for the project and the SCHEDULE for the project should have been defined. Any evaluation of the system should determine whether or not the system has been built in accordance with objectives related to scope, scheduling and costs. SCOPE CREEP is a common problem which occurs when users start deciding that they want new features added to their system part way through the project. This affects the schedule for completing tasks and it increases the cost of the system because new design and coding needs to be paid for. Also, a change of scope is likely to mean having to go back over completed work to ensure that proposed new features do not affect other parts of the system. After the system is built and tested it is then possible to accurately determine costs and from there determine future benefits accrued in the form of a return on investment (RIO).