LESSON 5 - System Analysis

• Systems analysis


  a problem-solving technique that decomposes a system into its component pieces for the purpose of studying how well those component parts work and interact to accomplish their purpose.
• Systems design 


  a complementary problem-solving technique (to systems analysis) that reassembles a system’s component pieces back into a complete system—hopefully, an improved system.

  
  

  This may involves adding, deleting, and changing pieces relative to the original system.
• Information systems analysis


  those development phases in an information systems development project the primarily focus on the business problem and requirements, independent of any technology that can or will be used to implement a solution to that problem.
• Repository 


  a location (or set of locations) where systems analysts, systems designers,

  and system builders keep all of the documentation associated with one or more systems or projects.
• Model-driven analysis


  a problem-solving approach that emphasizes the drawing of pictorial system models to document and validate both existing and/or proposed systems.

  
  

  Ultimately, the system model becomes the blueprint for designing and constructing an improved system.
• Model 


  a representation of either reality or vision.
• Structured analysis


  a model-driven, process-centered technique used to either analyze an existing system, define business requirements for a new system, or both.

  
  

  The models are pictures that illustrate the system’s component pieces: processes and their associated inputs, outputs, and files.
• Information engineering (IE) 


  a model-driven and data-centered, but process-sensitive technique for planning, analyzing, and designing information systems.

  
  

  this models are pictures that illustrate and synchronize the system’s data and processes.
• Object-oriented analysis (OOA)


  a model-driven technique that integrates data and process concerns into constructs called objects.

  
  

  this models are pictures that illustrate the system’s objects from various perspectives such as structure and behavior, and interactions of the objects.
• Object


  the encapsulation of the data (called properties) that describes a discrete person, object, place, event, or thing, with all the processes (called methods) that are allowed to use or update the data and properties. The only way to access or update the object’s data is to use the object’s predefined processes.
• Accelerated systems analysis


  approaches emphasize the construction of prototypes to

  more rapidly identify business and user requirements for a new system.
• Prototype


  a small-scale, incomplete, but working sample of a desired system.
• Accelerated systems analysis approaches

  • Discovery Prototyping
  • Rapid Architected Analysis
• Discovery Prototyping


  a technique used to identify the users’ business requirements by having them react to a quick-and-dirty implementation of those requirements.
• Rapid architected analysis


  an approach that attempts to derive system models (as described earlier

  in this section) from existing systems or discovery prototypes.
• Reverse engineering


  the use of technology that reads the program code for an existing database, application program, and/or user interface and automatically generates the equivalent system model.
• Requirements discovery


  the process, used by systems analysts of identifying or extracting system problems and solution requirements from the user community.
• Approaches of Requirements Discovery

  • Fact-Finding
  • Joint Requirement Planning (JRP)
• Fact-Finding


  the process of collecting information about system problems, opportunities, solution requirements, and priorities.
• Joint requirements planning (JRP)


  the use of facilitated workshops to bring together all of the system owners, users, and analysts, and some systems designer and builders to jointly perform systems analysis.
• Business process redesign (BPR)


  the application of systems analysis methods to thegoal of dramatically changing and improving the fundamental business processes of an organization, independent of information technology.
• Agile method


  the integration of various approachesof systems analysis and design for applications as deemed appropriate to the problem being solved and the system being developed.
• FAST Systems Analysis Phases

  • Scope Definition Phase
  • Problem Analysis Phase
  • Requirements Analysis Phase
  • Logical Design Phase
  • Decision Analysis Phase
• Steering body


  a committee of executive business and system managers that studies and prioritizes competing project proposals to determine which projects will return the most value to the organization and thus should be approved for continues systems development.

  also called a steering committee
• Project charter


  the final deliverable for the preliminary investigation phase.

  
  

  it defines the project scope, plan, methodology, standards, and so on.
• Cause-and-effect analysis


  a technique in which problems are studied to determine their causes and effects.
• Objective


  a measure of success. It is something that you expect to achieve, if given sufficient resources.
• Constraint 


  something that will limit your flexibility in defining a solution to your objectives.
• Functional requirement


  a description of activities and services a system must provide.

  inputs, outputs, processes, stored data
• Nonfunctional requirement


  a description of other features, characteristics, and constraints that define a satisfactory system.

  Performance, ease of learning and use, budgets, deadlines, documentation, security, internal auditing controls
• Draft Functional and Nonfunctional Requirements


  Could use simple list of system improvement objectives

  Increasingly systems analysts express functional requirements using Use Cases
• Use case 


  a business scenario or event for which the system must provide a defined response.

  
  

  evolved out of object-oriented analysis; however, their use has become common in many other methodologies for systems analysis and design.
• Timeboxing 


  a technique that delivers information systems

  functionality and requirements through versioning.
• Feasibility

  • Technical feasibility
  • Operational feasibility
  • Economic feasibility
  • Schedule feasibility
• Since “a picture is worth a thousand words,” most models use pictures to represent the reality or vision.
• Joint Application Development (JAD)


  JRP is generally part of a larger method

  a more comprehensive application of the JRP techniques to the entire systems development process
• Mandatory requirement


  is one that must be fulfilled by the minimal system, version 1.0
• Desirable requirement 


  is one that is not absolutely essential to version 1.0

  it may be essential to the vision of a future verion