Docstoc

www.radford.eduitec100textsswt3ch10.ppt

Document Sample
www.radford.eduitec100textsswt3ch10.ppt Powered By Docstoc
					     Chapter 10:
Systems Development
Objectives
• Describe the systems development life cycle,
  who participates in it and why it is important
• Discuss systems development tools
• Understand how systems development projects
  are investigated




               Succeeding with Technology, Third Edition   2
Objectives
• Describe how an existing system can be
  evaluated
• Discuss what is involved in planning a new
  system
• List the steps to implement a new or modified
  system
• Describe the importance of updating and
  monitoring a system


               Succeeding with Technology, Third Edition   3
Chapter Content
•   An Overview of Systems Development
•   Tools and Techniques for Systems Development
•   Systems Investigation
•   Systems Analysis




                Succeeding with Technology, Third Edition   4
Chapter Content
• Systems Design
• Systems Implementation
• Systems Maintenance and Review




              Succeeding with Technology, Third Edition   5
An Overview of Systems Development
• Systems development process
  – Includes a wide range of projects
     • Purchasing a small program
     • Installing a huge system including hardware, software,
       communications equipment, and personnel
  – Typically called a systems development life cycle
    (SDLC)




                  Succeeding with Technology, Third Edition     6
An Overview of Systems Development
• Systems investigation and analysis
  – Looks at the existing system and determines if it can and
    should be improved
• Systems design and implementation
  – Selecting and planning the best solution
  – Modifying an existing system or developing a new one, placing
    the best solution into effect
• Maintenance and review
  – Evaluating the results of the solution
  – Makes sure that the new or modified system is operating as
    intended
                   Succeeding with Technology, Third Edition        7
An Overview of Systems Development




           Succeeding with Technology, Third Edition   8
Participants in Systems Development
• System stakeholders
  – Individuals who will benefit from systems
    development project
• Users
  – Individuals who will be interacting with the system
    on a regular basis
• Managers
  – People most capable of initiating and maintaining
    change

                 Succeeding with Technology, Third Edition   9
Participants in Systems Development
• Systems development specialists
  – Project leader
     • Individual in charge of the systems development effort
  – Systems analyst
     • Specializes in analyzing and designing systems
  – Software engineer or computer programmer
     • Responsible for modifying or creating programs to satisfy
       user requirements
  – Computer systems management
     • Includes the chief information officer (CIO) and other
       technicians
                   Succeeding with Technology, Third Edition       10
Participants in Systems Development




            Succeeding with Technology, Third Edition   11
Why Start A Systems
Development Project?
• Several reasons:
  – Problems with existing systems
  – Mergers
  – Competition
  – Pressure from government agencies




               Succeeding with Technology, Third Edition   12
Why Start A Systems
Development Project?
• Creative analysis
   – Investigating new approaches to existing problems
• Critical analysis
   – Being skeptical and doubtful
   – Questioning whether or not the current computer
     system is still effective and efficient
• Systems development process
   – Begins with gathering information on users’ needs


                 Succeeding with Technology, Third Edition   13
Systems Development Planning
• System development planning
  – Translation of organized or individual goals into
    systems development initiatives




                 Succeeding with Technology, Third Edition   14
End-User Systems Development
• End-user systems development
  – Development of computer systems by individuals
    outside of the formal planning and departmental
    structure
  – Range from small to significant
     • Software routine to merge data with form letters
     • Customer contact databases




                  Succeeding with Technology, Third Edition   15
End-User Systems Development




          Succeeding with Technology, Third Edition   16
Tools and Techniques for
Systems Development
• Systems development tools
  – Can greatly simplify the systems development
    process
  – Include
     •   Computer-aided software engineering tools (CASE)
     •   Flowcharts, decision tables
     •   Project management software
     •   Prototyping
     •   Outsourcing and object-oriented systems development



                    Succeeding with Technology, Third Edition   17
Computer-Aided Software Engineering
• Software engineering
  – Employs computer-aided software engineering
    (CASE) tools
• CASE tools
  – Automate many systems development tasks
  – Allow more than one person to work on the same
    system at the same time via a multiuser interface




                Succeeding with Technology, Third Edition   18
Computer-Aided Software Engineering




           Succeeding with Technology, Third Edition   19
Flowcharts
• Chart the path from a starting point to the final
  destination
• Can display various amounts of detail
• When developing a system
  – General flowchart describes the overall purpose and
    structure of the system




                Succeeding with Technology, Third Edition   20
Flowcharts




             Succeeding with Technology, Third Edition   21
Flowcharts




             Succeeding with Technology, Third Edition
Decision Tables
• Can be used as an alternative to or in
  conjunction with flowcharts
• In general, a decision table displays
  – The various conditions that could exist
  – The different actions that the computer should take




                Succeeding with Technology, Third Edition   23
Decision Tables




           Succeeding with Technology, Third Edition   24
Project Management Tools
• Purpose is to plan, monitor, and control necessary
  development activities
• Program Evaluation and Review Technique (PERT)
   – Creates three time estimates for an activity
      • The shortest possible time
      • The most likely time
      • The longest possible time
• Gantt charting
   – A grid that lists activities and deadlines
• Project crashing
   – Reducing project completion time

                      Succeeding with Technology, Third Edition   25
Project Management Tools




          Succeeding with Technology, Third Edition   26
Project Management Tools




          Succeeding with Technology, Third Edition   27
Prototyping
• The creation of a preliminary model or version of
  a major subsystem
• Iterative approach to systems development
  – Each phase of the SDLC is repeated several times
    (iterated)




                Succeeding with Technology, Third Edition   28
Prototyping




          Succeeding with Technology, Third Edition   29
Outsourcing
• Use of outside company to take over portions of
  its workload
• Challenges and disadvantages
  – Internal experience and loyalty can suffer
  – People can lose jobs and be very emotional
  – Once outside company leaves, internal employees
    lack experience
  – Difficult to compete when using the same companies



                Succeeding with Technology, Third Edition   30
Object-Oriented Systems Development
• An extension of object-oriented programming
• Can be used during all phases of systems
  development
• Organizations
  – Have saved time and money using the object-
    oriented approach to systems development
• Objects can be diagrammed
  – Actor and use case


                Succeeding with Technology, Third Edition   31
Object-Oriented Systems Development




            Succeeding with Technology, Third Edition   32
Systems Investigation
• Overall purpose
   – Determine whether objectives of existing system satisfy the
     goals of the organization
• Attempts to answer the following questions
   – What primary problems might a new or enhanced system
     solve?
   – What opportunities might a new or enhanced system provide?
   – What new hardware, software, databases,
     telecommunications, personnel, or procedures will improve
     the existing system or are required for a new system?
   – What are the potential costs?
   – What are the associated risks?
                    Succeeding with Technology, Third Edition      33
Feasibility Analysis
• Technical feasibility
   – Concerned with whether or not hardware/software
     can be acquired or developed to solve the problem
• Economic feasibility
   – Determines if the project makes financial sense
• Legal feasibility
   – Determines whether laws or regulations may prevent
     or limit a systems development project



                 Succeeding with Technology, Third Edition   34
Feasibility Analysis
• Operational feasibility
  – Measure of whether or not the project can be put
    into action or operation
• Schedule feasibility
  – Determines if the project can be completed in a
    reasonable amount of time




                Succeeding with Technology, Third Edition   35
Feasibility Analysis




            Succeeding with Technology, Third Edition   36
Systems Analysis
• Attempts to understand how the existing system
  helps solve the problem identified in systems
  investigation
• Overall emphasis
  – To gather data on the existing system and the
    requirements for the new system
  – To consider alternative solutions to the problem and
    the feasibility of the solutions



                Succeeding with Technology, Third Edition   37
General Analysis Considerations
• Formalized analysis procedure involves
  – Collecting appropriate data
  – Analyzing the data
  – Determining new system requirements and project
    priorities




               Succeeding with Technology, Third Edition   38
Collecting Data
• Purpose
  – To seek additional information about problems
    identified during systems investigation
• Techniques
  – Interviews
  – Direct observation
  – Outputs
  – Questionnaires
  – Other Data Collection Methods

                Succeeding with Technology, Third Edition   39
Collecting Data




           Succeeding with Technology, Third Edition   40
Collecting Data




           Succeeding with Technology, Third Edition   41
Requirements Analysis
• Purpose
  – To determine user, stakeholder, and organizational
    needs
• Tools and techniques
  – Asking Directly
  – Critical Success Factors
  – Joint Application Development
  – Rapid Application Development



                Succeeding with Technology, Third Edition   42
Requirements Analysis




          Succeeding with Technology, Third Edition   43
Systems Design
• Overall purpose
  – To select and plan a system that meets the
    requirements needed to deliver the problem solution
• Results
  – A new or modified system




                Succeeding with Technology, Third Edition   44
Generating Systems Design Alternatives
• First step of design
  – Investigate alternatives for all components
• Request for information (RFI)
  – Asks a computer systems vendor to provide
    information about its products or services
• Request for quotes (RFQ)
  – Asks a computer systems company to give prices for
    its products or services
• Request for proposal (RFP)
  – Generated during systems development
                 Succeeding with Technology, Third Edition   45
Generating Systems Design Alternatives




             Succeeding with Technology, Third Edition   46
Evaluating and Selecting a Systems Design
• Evaluate design alternatives
• Select the best solution for supporting your
  needs
  – Cost comparisons
  – Hardware performance
  – Delivery dates
  – Price
  – Storage capabilities
  – Training
  – Computer speed

                Succeeding with Technology, Third Edition   47
The Contract
• Most vendors provide standard contracts
  – Designed to protect the vendor, not the organization
    buying the equipment
• Organizations are creating their own contracts,
  clearly stating
  – Equipment and software specifications
  – Training
  – Installation
  – Maintenance


                Succeeding with Technology, Third Edition   48
Systems Implementation
• Includes
  – Hardware acquisition
  – Software acquisition or development
  – User preparation
  – Hiring and training of personnel
  – Site and data preparation
  – Installation, testing, startup, and user acceptance




                 Succeeding with Technology, Third Edition   49
Acquiring Hardware
• Most people and organizations acquire hardware
  and computers by
  – Purchasing, leasing, or renting computer resources
    from a computer systems vendor
• “Pay as you go computing”
  – Organization pays only for the computer power it
    uses




                Succeeding with Technology, Third Edition   50
Selecting and Acquiring Software:
Make, Buy, or Rent
• Program development life cycle
  – Program specification
     • Description of what the software must accomplish
  – Algorithm
     • Step-by-step sequence of computer instructions
  – Syntax errors
     • Errors in the use of the programming language syntax
  – Logic errors
     • Errors in the programming logic


                   Succeeding with Technology, Third Edition   51
Selecting and Acquiring Software:
Make, Buy, or Rent
• Software as a service (SaaS)
  – Software resides on vendor’s server
• Application service provider (ASP)
  – Develops, maintains, stores software and makes it
    available over the Internet




                Succeeding with Technology, Third Edition   52
Acquiring Database and
Telecommunications Systems
• A database is one of the most important parts of
  system development
   – Many projects involve a database
   – May require both hardware and software acquisition
• Telecommunications is one of the fastest growing business
  applications
   – May require both hardware and software acquisition




                   Succeeding with Technology, Third Edition   53
Acquiring Database and
Telecommunications Systems




            Succeeding with Technology, Third Edition   54
User Preparation
• Readying users and stakeholders for the new or
  modified system
• Can include
  – Marketing
  – Training
  – Documentation
  – Support




               Succeeding with Technology, Third Edition   55
User Preparation




          Succeeding with Technology, Third Edition   56
Computer Systems Personnel:
Hiring and Training
• Depending on the size of your new system,
  personnel may have to be
  – Trained
  – Hired
• Systems may need
  – Systems manager
  – Programmers
  – Data entry operators
• The success of any computer system depends on
  the way it is used by the personnel within the
  organization
                  Succeeding with Technology, Third Edition   57
Site Preparation
• Location of the new system needs to be
  prepared
• For a small system
  – May mean rearranging the furniture
• Larger systems
  – May require special wiring and air conditioning




                 Succeeding with Technology, Third Edition   58
Data Preparation
• Converting manual files into computer files
• Data conversion
  – May be required to transform the existing
    computerized files into the proper format
• Permanent data
  – Must be placed on a permanent storage device




                Succeeding with Technology, Third Edition   59
Installation
• Placing computer equipment on the site and
  making it operational
• For a small systems development project
  – May require making room on top of a desk for a new PC
  – Plugging it into a wall outlet
  – Following the manufacturer’s instructions to turn it on
• Larger projects are usually completed by the
  manufacturer



                    Succeeding with Technology, Third Edition   60
Testing
• Unit testing
  – Developing test data that will force the computer to
    execute every statement in the program
• System testing
  – Requires the testing of all programs together
• Volume testing
  – Ensures that entire system can handle a large
    amount of data under normal operating conditions



                 Succeeding with Technology, Third Edition   61
Testing
• Integration testing
  – Ensures that new programs can interact with other
    major applications
• Acceptance testing
  – Ensures that new or modified system is operating as
    intended




                Succeeding with Technology, Third Edition   62
Testing




          Succeeding with Technology, Third Edition   63
Startup
• Direct conversion
  – Stopping the old system and starting the new one on
    a given date
• Phase-in approach
  – New system is slowly phased in, while old one is
    slowly phased out
• Pilot startup
  – Running a pilot or small version of the new system
    along with the old

                  Succeeding with Technology, Third Edition   64
Startup




          Succeeding with Technology, Third Edition   65
User Acceptance and Documentation
• User acceptance document
  – Agreement signed by user that a phase of the
    complete system is approved
• Documentation
  – Includes all materials that describe the new or
    modified system




                 Succeeding with Technology, Third Edition   66
User Acceptance and Documentation
• Systems documentation
  – Describes the technical aspects of the new or
    modified system
• User documentation
  – Describes how the system can be used by
    noncomputer personnel




                Succeeding with Technology, Third Edition   67
Systems Maintenance and Review
• Final steps of systems development
• Involves checking, changing, and enhancing the
  system to make it serve the organization better




               Succeeding with Technology, Third Edition   68
Reasons for Maintenance
• New requests from stakeholders, users, and
  managers
• Bugs or errors in the program
• Technical and hardware problems
• Corporate mergers and acquisitions
• Governmental regulations that require changes
  in programs



               Succeeding with Technology, Third Edition   69
Financial Implications of Maintenance
• For older programs
  – Cost of maintenance can be up to five times greater
    than cost of development
• Average programmer
  – Can spend from 50% - over 75% of his/her time
    maintaining programs
• Important to keep track of why systems are
  maintained as well as the cost of maintenance


                Succeeding with Technology, Third Edition   70
Financial Implications of Maintenance




            Succeeding with Technology, Third Edition   71
Systems Review
• Final phase of the systems development life
  cycle
  – Analyzing systems to make sure that they are
    operating as intended
• Two types of review procedures
  – Event-driven review
  – Time-driven review
• Continuous improvement approach
  – Make changes even when small problems or
    opportunities arise
                Succeeding with Technology, Third Edition   72
Summary
• Phases of the SDLC
  – Investigation, analysis, design, implementation, maintenance,
    review
• Common system development tools and
  techniques
  – CASE tools
  – Flowcharts
  – Decision tables
• Systems investigation
  – First step in the development of a new or modified computer
    system
                      Succeeding with Technology, Third Edition     73
Summary
• Systems analysis
  – The examination of existing systems
• Systems design
  – Prepares detailed design needs for new system or
    modifications to the existing one
• Systems implementation
  – Includes hardware acquisition, software acquisition or
    development, and user preparation
• Systems maintenance
  – Involves checking, changing, and enhancing the system

                   Succeeding with Technology, Third Edition   74

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:0
posted:4/29/2013
language:Unknown
pages:74