for the Small Enterprise
Systems Analysis and Design
section I
Introduction
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
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 . . .
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.. . .
Systems definition example
Systems definition example
Car as a System
• Car
– Propulsion (engine)
• Fuel
• Electrical
– Comfort
• Temperature
• Entertainment
– Radio
– TV / Video
– Control
• Braking
• Steering
• Acceleration
– Signal
– Safety
• Starting
• Seatbelts
• Air bags
– Monitoring
•
•
•
•
Speedometer
Odometer
Temperature
Oil
The concept of a system
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How do the “rules” change
7
How do the “rules” change
8
Systems definition example
System: An interrelated set of components, with an identifiable
boundary, working together for some purpose
General System Depiction
Environment: Everything external to a system that interacts with the system.
General System Depiction
Boundary: The line that marks the inside and outside of a system and that sets
off the system from its environment.
General System Depiction
Components: An irreducible part or aggregation of parts that make up a
system, also called a subsystem..
General System Depiction
Interrelationship: Dependence of one subsystem on one or more
subsystems.
General System Depiction
Input: Whatever a system takes from its environment in order to fulfill its purpose.
General System Depiction
Output: Whatever a system returns to its environment in order to fulfill its
purpose.
General System Depiction
Interfaces: Point of contact where a system meets its environment or where
subsystems meet each other.
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 analyst’s 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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TECHNOTE 1-1
Computing Terminology
Several software products are integral to the
analyst’s 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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TECHNOTE 1-2
Software Classifications
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)
30
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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