SAD

• System Analysis


  Finding out what the new system is able to do, rather than how
• System Analysis process


  1. Fact-Finding

  2. Documentation
• Fact-Finding


  • An exercise where all prospective users of the new system should contribute to determining requirements
  • Fact-finding techniques are used to ascertain the user's needs and these are summarized using a requirements specification and a range of diagramming methods
• Documentation


  • Detailed systems design follows the analysis stage and it needs to be based on unambiguous documentation and diagrams from the analysis stage

  
• Objective of systems analysis phase


  Understand the proposed project, ensure that it will support business requirements, and build a solid foundation for system development
• Requirements Modeling


  Investigation and fact-finding to describe the current system and define the requirements for the new system. It will include all the outputs, inputs, processes, and controls for the new system. The model will consist of various diagrams, charts, and documentation

  
• System Requirements Document


  End product of the systems analysis, overall design blueprint for the new system
• Categories of System Requirements


  • Outputs
  • Inputs
  • Processes
  • Performance
  • Controls
• Outputs


  Refer to electronic or printed information produced by the system
• OutputsExamples


  • The website must report online volume statistics every four hours, and hourly during peak periods
  • The purchasing system must provide suppliers up-to-date list of all sales reps
  • The contact management system must generate a daily reminder list for all sales reps
  • Purchasing system must provide suppliers with up-to-date specifications
  • The sales tracking system must produce a daily fast-moving-item report, listing all products that exceed the forecasted sales volume grouped by style, color, size, and reorder status
• Inputs


  Refer to the necessary data that enters into the system either manually or in an automated manner
• Inputs 


  • Student grades must be entered on machine-scannable forms prepared by the instructor
  • Manufacturing employees must swipe their ID cards into online data collection terminals
  • Data entry screen must be uniform, except background color, which can be changed by the user
• Processes


  Refer to the logical rules that are applied to transform the data into meaningful information
• Processes


  • The student record must calculate the GPA at the end of each semester
  • The video rental system must not execute new rental transactions for customers who have overdue tapes
  • The prescription system must automatically generate an insurance claim form
• Performance


  Refers to system characteristics such as speed, volume, capacity, availability, and reliability
• Performance


  • The system must support 25 users online simultaneously
  • Response time must not exceed four seconds
  • The system must be operational seven days a week, 365 days a year
  • The student records system must produce class lists within five hours after the end of registration
• Security/Controls


  Refers to hardware, software and procedural controls that safeguard and protect the system and its data from internal or external threats
• Security/Controls

  • The system must provide log-on security at the operating system level and at the application level
  • All transactions must have an audit trails
  • An employee record must be added, changed or deleted only by a member of the human resource department
• Functional Requirements


  Statements of services the system should provide, how the system should react to particular inputs, and how the system should behave in particular situations
• Non-Functional Requirements


  Refer to behavioral properties that the system must have, such as performance, reliability, response time, security and usability etc. Non-functional requirements may be more critical than functional requirements. If one is not met, the system may be useless
• Types of Non-Functional Requirements


  • Operational
  • Performance
  • Usability
  • Security
  • Reliability
• Technical/Operational Requirements


  Describe operational characteristics related to an organization's environment, hardware and software
• Technical/Operational Requirements


  • The client component may require to operate on a portable and desktop PC's running the Windows OS and browsers using Chrome or Firefox version 13
• Performance Requirements


  Describe operational characteristics related to workload measures such as throughput and response time
• Performance Requirements


  • The client side may be required to have one-half second response time on all screens
  • The server side may need to support 100 simultaneous client sessions
• Usability Requirements


  Describes operational characteristics related to users, such as the interface, work procedures, online help and documentation
• Usability Requirements


  • A web based interface may be required to follow organization wide graphic design guidelines such as menu placement and format, color schemes, use of organization's logo and required disclaimers
• Security Requirements


  Describes the user access to certain functions and the conditions under which access is granted
• Security Requirements


  • The system must provide log-on security at the operating system level and at the application level
  • All transactions must have an audit trails
• Reliability Requirements


  Describes the dependability of a system such as services outages, incorrect processing, and error detection and recovery
• Scalability


  A system's ability to handle increased business volume and transactions in the future. Because it will have a longer useful life, a scalable system offers a better return on the initial investment
• Total Cost of Ownership (TCO)


  Includes all future operational and support costs, in addition to direct costs. It is especially important if the development team is assessing several alternatives
• Fact-Finding


  Involves answers to five familiar questions: What, When, Where, Why and How. Software helps you gather and analyze facts; however, it cannot perform fact-finding for you. The systems analyst first must understand the current situation. Only then can he or she tackle the question of what should be done
• Interview


  A planned meeting during which you obtain information from another person. Interviewing is an important method for collecting data on information system requirements
• Information revealed by interviews


  • Interviewee opinions
  • Interviewee feelings
  • About the current state of the system
  • Organizational and personal goals
  • Informal procedures
• Guidelines for effective interviewing


  • Plan the interview
  • Listen carefully and take notes (record if permitted)
  • Review notes within 48 hours of interview
  • Be neutral
  • Seek diverse views
• Interview Steps


  1. Determine the people to interview

  2. Establish objectives for the interview

  3. Develop interview questions

  4. Prepare for the interview

  5. Conduct the interview

  6. Document the interview

  7. Evaluate the interview
• Open-ended questions


  Questions in interviews that have no prespecified answers, encourage spontaneous and unstructured responses
• Close-ended questions


  Restrict the response; provide a range of answers from the interviewee may choose
• Close-ended questions


  • True or False
  • Multiple Choice
  • Rating a response or idea on some scale
  • Ranking items in order of importance