Systems Planning, Development, and Implementation

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Chapter 9

• Systems Planning, Development, and Implementation

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Key Systems Development Concepts

• Systems development life cycle (SDLC)
• Refers to stages in the conception, design,
  creation, and implementation of an information
  system

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Key Systems Development Concepts

• Stages of the SDLC
• Needs assessment
• Describes a formal, integrated, and usually
  time-limited process of gathering data about the
  needs and opportunities of end users and their
  managers
• Alternative analysis
• Considers one or more alternate designs and
  analyzes their advantages and disadvantages

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Key Systems Development Concepts

• Stages of the SDLC
• Design
• Refers to the creation of detailed specifications
  for the proposed system
• Development
• Refers to the creation or purchase of the
  hardware and software necessary to implement the
  design

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Key Systems Development Concepts

• Stages of the SDLC
• Implementation
• Refers to deactivating the old system and
  activating the new one
• Maintenance
• Refers to fixing errors, or bugs, in the way that
  the system operates

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Key Systems Development Concepts
Figure 9-1
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System Developmentas a Process
Figure 9-2
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Key Systems Development Concepts

• Development Pathways
• The waterfall model
• Like water flowing over a waterfall, the
  development moves in only one direction, so
  stages cannot be repeated
• The spiral approach
• Implements systems based on the concept of
  greatest need

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Key Systems Development Concepts

• Development Pathways
• Prototyping
• Describes an approach that tries to satisfy user
  needs by focusing on the user interface
• Agile programming
• A name given to several methodologies that focus
  on being reactive to changing user demands and
  target small development groups and projects that
  require minimal documentation

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Systems Modeling

• Data Models
• Describe the relationships among the elements of
  data that an organization uses
• Example Entity/relationship model

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Systems Modeling

• Process Models
• Divide a process into its parts, show how these
  parts relate to one another, and indicate which
  outputs of one process are input to other
  processes
• Examples
• Structure charts
• Function boxes
• Data flow diagrams

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Systems Modeling

• Object Models
• Describe the properties of objects, their
  relationship to one another, and the functions
  they perform
• Examples
• Inheritance diagrams
• State diagrams

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Computer Aided Software Engineering (CASE)

• Use of software to automate activities performed
  in needs assessment, systems analysis, design,
  development, and maintenance
• CASE suits called CASE toolset or CASE
  workbench

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Stages of the Life Cycle

• 1. Needs Assessment
• Identifies the information needs of an
  organization

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Stages of the Life Cycle

• 1. Needs Assessment
• Collecting Information For Needs Assessment
• Output analysis
• Input analysis
• Procedure analysis
• Systems analysts help provide this function by
  acting as an interface between information
  systems users and developers

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Stages of the Life Cycle

• 1. Needs Assessment
• Methodologies and tools
• Contextual inquiry
• Structured analysis
• Data dictionary
• Reverse engineering

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Stages of the Life Cycle

• 2. Alternative Analysis
• Identification and evaluation of alternative
  systems, ultimately focusing on a single design
  more extensively
• Alternative analysis tools
• Return on investment analysis
• Risk analysis

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Stages of the Life Cycle

• 3. Design
• Providing detailed specifications for the
  selected design

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Stages of the Life Cycle

• 3. Design
• Interface design
• Refers to the specification of the media,
  content, and form of input and output
• Data design
• Refers to creating the model of data supporting
  the system

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Stages of the Life Cycle

• 3. Design
• Process design
• Refers to the design of both the computational
  and logical processes underlying the system
• Object design
• Refers to the generation of an object model

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Stages of the Life Cycle

• 3. Design
• Physical design
• Refers to decisions about the hardware used to
  deliver the system
• Test design
• Refers to the creation of tests that ensure the
  proper operation of developed systems

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Stages of the Life Cycle

• 3. Design
• Design specification
• Refers to means for communicating the design to
  the programmers who will implement it

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Stages of the Life Cycle

• 4. Development
• Includes development or purchase of software,
  potentially the procurement of hardware, and
  testing of the new system

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Stages of the Life Cycle

• 4. Development
• Development tools
• Screen generators
• Report generators
• Code generators

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Stages of the Life Cycle

• 4. Development
• Testing levels for quality assurance
• Unit testing
• Component testing
• Integration testing
• Systems testing
• Testing stages
• Performance testing
• Usability testing

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Stages of the Life Cycle

• 5. Implementation
• Direct cut-over strategy
• Describes the replacement of the old with the new
  system overnight or over some other period of
  time when the company does not operate

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Stages of the Life Cycle

• 5. Implementation
• Pilot implementation strategy
• Requires one or more segments of a company to use
  a new system before the entire company uses it

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Stages of the Life Cycle

• 5. Implementation
• Phased implementation strategy
• Introduces components of the new system one at a
  time

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Stages of the Life Cycle

• 5. Implementation
• Parallel implementation strategy
• Refers to the use of both the new and the old
  system for a period of time

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Stages of the Life Cycle

• 6. Maintenance
• Refers to all activities related to a system
  after it is implemented and before a full-fledged
  needs assessment

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Developing andManaging Web Sites

• Protection of customers data
• Protection of operational data
• Protection of trade secrets
• Protection of access

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Why Systems Development Projects Succeed or Fail

• Risk
• Scope
• Management
• Process
• Resources

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End of Chapter 9

• Systems Planning, Development, and Implementation