section I Introduction

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section I Introduction
for the Small Enterprise
Systems Analysis and Design
information systems defined small enterprise
characteristics Information needs of the small
enterprise the systems development life
cycle computer information system components the
role of the analyst methodologies, tools, and
techniques the enhanced SDLC portfolio project
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Systems definition

• a set of entities, real or abstract, comprising a
  whole where each component interacts with or is
  related to at least one other component.
• Any object which has no relation with any other
  element of the system is not part of that system
  but rather of the system environment.
• A subsystem then is a set of elements, which is
  a system itself, and a part of the whole system.
• In other words . . .

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Systems definition

• A system is composed of regularly interacting or
  interrelating groups of activities/parts which,
  when taken together, form a new whole. In most
  cases this whole has properties which cannot be
  found in the constituent elements.. . .

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Systems definition example
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Systems definition example
Car as a System

• Car
• Propulsion (engine)
• Fuel
• Electrical
• Control
• Braking
• Steering
• Acceleration
• Signal
• Safety
• Starting
• Seatbelts
• Air bags

• Comfort
• Temperature
• Entertainment
• Radio
• TV / Video
• Monitoring
• Speedometer
• Odometer
• Temperature
• Oil

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The concept of a system
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How do the rules change
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How do the rules change
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Systems definition example
System An interrelated set of components, with
an identifiable boundary, working together for
some purpose
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General System Depiction

• Environment Everything external to a system that
  interacts with the system.

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General System Depiction

• Boundary The line that marks the inside and
  outside of a system and that sets off the system
  from its environment.

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General System Depiction

• Components An irreducible part or aggregation of
  parts that make up a system, also called a
  subsystem..

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General System Depiction

• Interrelationship Dependence of one subsystem on
  one or more subsystems.

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General System Depiction

• Input Whatever a system takes from its
  environment in order to fulfill its purpose.

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General System Depiction

• Output Whatever a system returns to its
  environment in order to fulfill its purpose.

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General System Depiction

• Interfaces Point of contact where a system meets
  its environment or where subsystems meet each
  other.

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Information Systems Defined

• An information system is a well-coordinated
  collection of resources that gather and transform
  data into information products and services that
  help the enterprise perform its designed
  functions
• An information system hierarchy associates
  different classifications of information systems
  with different audiences

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Information System Hierarchy
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Information Systems Defined

• Three significant trends influence the
  evolution of information systems and provide
  opportunities for the entrepreneurial systems
  analyst
• The emergence of small enterprise computing
• The Internet as a dominating technology
• The maturation of application software

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Small Enterprise Characteristics

• The following small enterprise
  characteristics influence the analysts work
• Owner participation
• Economic constraints
• Competitive pressures

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Information Needs of the Small Enterprise

• The following are common information needs of
  any enterprise
• Production and inventory
• Personnel
• Financial reporting
• Marketing, sales, and service
• Customer relations

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Computing Terminology
TECHNOTE 1-1

• Several software products are integral to the
  analysts work
• Off-the shelf application software
• Software suites
• Computer assisted systems engineering (CASE)
• Object-oriented application software

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The Systems Development Life Cycle

• The systems development life cycle (SDLC)
  consists of five major phases
• Analysis
• Design
• Development
• Implementation
• Maintenance

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The Circular SDLC
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The Recurring SDLC
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Information System Components

• There are six major information system
  components
• People
• Procedures
• Software
• Hardware
• Networks
• Data

Reference Figure 1-7 Information System
Components
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Software Classifications
TECHNOTE 1-2

• System Software
• Operating systems
• Firmware
• Utility
• Application Software
• Horizontal
• Vertical
• Turnkey
• Customizable Software
• Third-generation programming languages
• Fourth-generation programming language (4GL)
• Object-oriented programming language
• 4GL products

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The Role of the Analyst

• An agent of change
• A problem-solving strategist
• A group facilitator
• Four Sets of Analytical Skills
• Systems Thinking
• Organizational Knowledge
• Problem Identification
• Problem Analyzing and Solving

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The Blurred Proportional SDLC
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Methodologies, Tools, and Techniques

• CASE Tools
• Systems Architect
• Alternatives to CASE technologies (VISIO)

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The Enhanced SDLC

• The enhanced SDLC embodies several important
  concepts
• The recurring nature of the SDLC
• The blending of several phases of the SDLC
• The influence of the user throughout the SDLC
• The addition of many powerful tools to assist the
  analyst

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The Enhanced SDLC
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Chapter Summary (1/3)

• Small enterprise, PC-based computing should rely
  on proven systems theory and techniques
• The small enterprise approach presents special
  advantages for an introductory study of systems
  analysis
• The systems development life cycle provides a
  framework for creating a small enterprise
  information system

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Chapter Summary (2/3)

• There are five phases of the SDLC
• Analysis
• Design
• Development
• Implementation
• Maintenance
• There are six components of an information system
• People
• Procedures
• Software
• Hardware
• Networks
• Data

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Chapter Summary (3/3)

• A systems analyst is
• An agent of change
• A problem solving strategist
• A group facilitator
• Characteristics of a System
• Components
• Interrelated Components
• Boundary
• Purpose
• Environment
• Interfaces
• Input
• Output
• Constraints

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