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Introduction to System Analysis and Design

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Title: Introduction to System Analysis and Design


1
Introduction to System Analysis and Design
System Analysis and Design
  • - Dr. Mahmoud Abu-Arra
  • - Mr. Ahmad Al-Ghoul

2
Learning Objectives
  • Describe the systems development life cycle
  • Discuss Systems Development Guidelines

3
Introduction
  • Systems development life cycle (SDLC) is a common
    methodology for system development in many
    organizations it features several phases that
    mark the progress of the systems analysis and
    design effort
  • Every text book and information systems
    development organization uses a slightly
    different life cycle model
  • SDLC involves a series of phases.
  • You can think about SDLC like constructing a
    building. First, you would list specific
    objectives for the project. Then you might hire
    an architect to present an overall concept and
    create a set of drawings to show how the building
    will fulfill your objectives. Later, you would
    need detailed blueprints for the workers. When
    the building is done, you would check it out,
    test everything, turn it over to the new
    occupants, and make sure they are satisfy with
    the results.

4
The Systems Development Life Cycle
operation, security and support
Design and Implementation
Planning and Analysis
An idea
Time
5
The Systems Development Life Cycle
  • SDLC is Series of steps used to manage the phases
    of development for an information system
  • SDLC used to plan and manage the systems
    development process
  • The life cycle can be thought as a circular
    process in which the end of the useful life of
    one system leads to the beginning of anther
    project that will develop a new version or
    replace an existing system altogether
  • SDLC is not necessary to be sequentially ordered
    set of phases, the specific steps and their
    sequence are meant to be adapted as required for
    a project
  • In a SDLC you can complete some activates in one
    phase in parallel with some activates of anther
    phase

6
The Systems Development Life Cycle
  • In some cases the SDLC is iterative that is,
    phases are repeated as required until an
    acceptable system is found
  • The SDLC used in an organization is an orderly
    set of activates conducted and planned for each
    development project
  • Each activity or phase in the SDLC has specific
    outcomes that feed important information to other
    phases

7
The Systems Development Life Cycle
  • Each of the phases include a set of steps, which
    rely on techniques that produce specific document
    files that provide understanding about the
    project.
  • Individual companies use customized life cycles

8
The Systems Development Life Cycle
  • Traditionally pictured as a waterfall model
  • In waterfall model the result of each phase,
    which is called end product, flaws sequentially
    into the next phase
  • The adjacent phases interact, as shown by dotted
    lines

9
The Systems Development Life Cycle
  • Alternative model
  • In the alternative model of the SDLC, planning,
    analysis, and design interact continuously,
    followed by implementation and operation and
    support
  • interactive model depicting real world practice
    and the constant dialog among users, managers,
    and systems developers

10
The Systems Development Life Cycle
  • System development life cycle includes the
    following steps
  • Systems planning
  • Systems analysis
  • Systems design
  • Systems implementation
  • Systems operation, support, and security

Planning
Analysis
Systems Operation and Support
Design
Implementation
11
The Systems Development Life Cycle
  • Systems planning
  • Purpose is to identify the nature and scope of
    the business opportunity or problem
  • Systems request begins the process describes
    problems or desired changes in an information
    system or business process
  • Systems planning includes preliminary
    investigation to identify the nature and scope
    of the business opportunity or problem. The
    outcome of preliminary investigation will affect
    the entire development process. A key part of the
    preliminary investigation is a feasibility
    study that reviews costs and benefits and
    recommends a course of action based on
    operational, technical, economic and time
    factors.

12
The Systems Development Life Cycle
  • Systems Analysis
  • Purpose is to build a logical model of the new
    system
  • The analysis phase answers the questions of who
    will use the system, what the system will do, and
    where and when it will be used.
  • During this phase the project team investigates
    any current systems, identifies improvement
    opportunities, and develops a concept for the new
    system.
  • First step is requirements modeling, where you
    investigate business processes and document what
    the new system must do. To understand the system,
    you perform fact-finding using techniques such as
    interviews, surveys, document review,
    observation, and sampling
  • End product is the System requirements document
    which describes management and user requirements,
    costs, and benefits, and outline alternative
    development strategies.

13
The Systems Development Life Cycle
  • Systems Design
  • In this phase the designer decided how the system
    will operate, in terms of the hardware, software,
    and network infrastructure the user interface,
    forms, and reports that will be used and the
    specific programs, databases, and files that will
    be needed.
  • Purpose is to create a blueprint that will
    satisfy all documented requirements
  • Identify all outputs, inputs, and processes
  • Avoid misunderstanding through manager and user
    involvement
  • End product is system design specification
  • Logical Design
  • Concentrates on business aspects of the system
  • Physical Design
  • Technical specifications

14
The Systems Development Life Cycle
  • Systems Implementation
  • New system is constructed
  • Write, test, document programs
  • File conversion occurs
  • Users, managers, IT staff trained to operate and
    support the system
  • System evaluation performed, to determine whether
    the system operates properly and if costs and
    benefits are within expectations.

15
The Systems Development Life Cycle
  • Systems Operation, Support, and security
  • New system supports operations
  • Maintenance changes correct errors or meet
    requirements
  • Enhancements increase system capability by
    provide new features and benefits
  • The objective during this phase is to maximize
    return on the IT investment
  • Security controls safeguard the system from both
    external and internal threats
  • A well-designed system will be secure, reliable,
    maintainable, and scalable so it can expand to
    meet new business requirements and volumes
  • After several years of operation, systems need
    extensive changes
  • SDLC ends with system replacement

16
Systems Development Guidelines
  • With experience as a system analyst, you will
    develop your own style and techniques. Although
    each project is different and have its
    constraints, rules, so you can decide which
    methods and technique you will use, you should
    consider some basic guidelines as you build an
    information system.
  • Planning
  • stick to an overall development plan
  • Involve users throughout the development process
  • Ensure that users are involved in the development
    process, especially when identifying and modeling
    system requirements
  • Listening is Very Important
  • The best system is the one that meets user needs
    most effectively. When you interact with users,
    you must put aside any preconceived notations and
    listen closely

17
Systems Development Guidelines
  • Create a Time Table with Major Milestones
  • Identify major milestones for project review and
    assessment. At those milestones, managers and
    systems developers must decide whether to proceed
    with the project, redo certain tasks, return to
    earlier phase, or terminate the project
  • Identify Interim Checkpoints
  • Establish interim checkpoints between major
    milestones to ensure that the project remains on
    schedule
  • Remain Flexible
  • System development is a dynamic process, and
    overlap often exists between the phases of system
    planning, analysis, design, and implementation
  • Develop Accurate Cost and Benefit Information
  • Provide accurate and reliable cost estimation and
    benefit information to managers at start of each
    phase

18
Sequence Summary
  • In this Sequence we have
  • Described the systems development life cycle
  • Distinguished between Traditional SDLC as a
    waterfall model and the Alternative SDLC model
  • Defined system planning, system analysis, system
    design, system implementation, System Operation,
    Support, and security
  • Discussed systems development guidelines

19
Reference
  • 1 System Analysis and Design, Sixth Edition
  • Authors Gary B. Shelly, Thomas J. Cashman and
    Harry J. Rosenblatt ,
  • Publisher SHELLY CASHMAN SEWIES.
  • 2 Modern Systems Analysis and Design Third
    Edition
  • Authors Jeffrey A. Hoffer , Joey F. George,
    Joseph S. Valacich
  • Publisher prentice hall
  • 3 System Analysis and Design, 3rd Edition
  • Authors Dennis, Wixom, Roth
  • Publisher John Wiley sons
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