System life cycles

• Stages in the system life cycle

  • Analysis
  • Design
  • Development and testing
  • Implementation
  • Documentation
  • Evaluation
• Analysis


  Collecting information about the present system and identifying problems
• Design


  Designing a new system to correct the problems identified in the analysis, it is when the design specification is produced
• Implementation


  Replacing the old system with the new system
• Documentation


  Creating technical and user documentation for new system
• Evaluation


  Evaluating whether the new system meets the requirements of the design requirements
• Analysis


  1. Finding out how the current system works

  2. Finding out what the requirements of the client are for the new system
• Methods of Research


  • Questionnaires
  • Interviews
  • Observation
  • Document analysis
• Questionnaires


  Used when there is a large number of users making it a larger sample, conducting interviews becomes impractical and hence the questionnaires are used as the results can be quantified and compared
• Questionnaires aren't suitable when there's a small number of users size since the sample size isn't large enough to gauge different onions and its much easier conduct their interviews rather than spending time creating an appropriate questionnaire
• Disadvantage of questionnaires


  It doesn't let the analyzer the opportunity to ask the users to elaborate on their answer without having to contact them again
• It's important for questions to be asked in a way in which the required information can be elicited from users and those responses can be analyzed and quantified collectively
• This could be done by providing appropriate multiple choices so that each response is counted
• The questionnaire shouldn't be long otherwise not many responses will be returned
• A mixture of multiple choice questions, opinion ratings and open questions should be used to allow a balance of quantitative analysis of closed questions and a qualitative analysis of open questions where users are able to suggest alternative ideas to those presented by the questionnaire
• Questions should also be written in a way which doesn't threaten the users and the way they currently do their work
• Users should also be given the opportunity to submit their questionnaires anonymously as it allows for more honest answers to be given
• It Is also ideal for them to be held online as it allows results to be immediately stored and readily available for detailed analysis in the form of graphs and tables
• Filters can be applied to the results and responses can be compared based on the answers given to another question
• Interviews


  Involve a direct conversation between the client and analysis
• Where there is a single end user or small group of end users then interviews are the perfect solution because questions can be asked of the users and conversation can take place which can expand upon answers that are given with follow up questions searching for further detail
• In large organizations, interviews can be used with key stakeholders or representatives of user groups
• Questions to be asked should be planned and designed to elicit the required information from the client, they could also vary depending on who is being interviewed
• However it could be difficult to hold an interview due to unavailability of the clients
• Clients could also answer dishonestly as interviews tend not to be anonymous, and they are afraid they might be judged by their answers
• The analyst also has to be fully involved with each interview which could result in a lot of cost and time being drained up early in the project
• Observation


  Involves the analyst watching the processes that take place within an organization to find out how everyday tasks are completed
• One disadvantage of this method is that user might do things differently from normal or they be more efficient when they know they r being observed, hence this doesn't give a true picture of what is happening
• This method can take up a lot of time however it is the most insightful method of finding out how an organization works
• Document analysis


  Existing documents within an organization an tell an analyst a lot about the information that is currently being used
• The analyst will need to see examples of any documents that show output information or five an indication of what data is being collected for input to a system

  
• The analyst can sometimes also identify processes that take place by looking at documents
• Its also possible to estimate the amount of data that Is likely to be required if the volume of the documents is known
• This method is not to be used on its own but must be used in conjunction with other analysis methods because its difficult to identify the processes just by looking at the documents
• Examination of the documents also only shows data that is currently output and doesn't give the opportunity to find out what additional data an organization might need or not need

  
• This information can be found out by following up documentation analysis with interviews
• User Requirements Specification


  It's a contract between the developer and the client, created by the analyst in consultation with the client who will approve it, specifying what the client needs the system to do so that developer can produce a system that meets the client's needs
• Contents of User Requirements Specification

  • The purpose of the system
  • The main objectives of the system
  • Data that must be output from the system (for example; invoices, sales report)
  • Data that needs to be input to the system to generate the outputs, including any screens or data collection forms
  • Validation and verification that is need for input data
  • Processes that need to take place to convert inputs into outputs or to store data
  • Data that need to be stored
  • Functional requirements such as performance measures
  • Deadlines for each milestone within the project
• System Specification


  It is created by the designer, listing all the software and hardware that is needed for the new system
• Software needs are identified first as the hardware depends on what software needs