Chapter 1: Introduction to
Systems Development
• Systems concepts
• The information systems infrastructure
• Top-down information systems development
• Methodologies and tools
• Keys to success as a systems developer
• The Functions/Components Matrix
Systems Concepts
• Physical and conceptual
• Open and closed
Fig 1.1: An Open System
Systems Concepts
• Open-loop and closed-loop
• The firm as a transformation system
Fig 1.2: A Closed-loop System
Systems Concepts
System levels
• Supersystem, suprasystem
• System
• Subsystem
Systems Concepts
The Control Mechanism
• Management
• Information professor
• Standards
Systems Concepts
Fig 1.7: Standards Information Flows to the Information
Processor
Systems Concepts
Fig 1.8: Decision Information Flows to the Physical System
Systems Concepts
The Feedback Loop
Fig 1.9: Information Flows to Management
Systems Concepts
Add some environmental flows and you have the
general systems model of the firm
• The manager uses the model.
• The systems developer uses the model.
Systems developers: Information specialists and
users working together
Systems Concepts
Fig 1.10: The General Systems Model of the Firm
The Information Systems Infrastructure
• Accounting Information System (AIS)
• Management Information System (MIS)
• Decision Support Systems (DSS)
• Office Automation Systems
• Expert Systems
The Information Systems Infrastructure
Fig 1.11: A System Structure
Top-down Information Systems
Development
Fig 1.12: Systems Development Planning Framework
Methodologies
• Traditional system development life cycle (SDLC)
• Prototyping
• Phased development
Fig 1.14: Phased Development Methodology
Tools
• Data modeling (ERDs, data dictionary)
• Process modeling (DFDs, structured
English)
• Object modeling (class, structure, statechart
diagrams, etc.)
Keys to Success as a System Developer
Fig 1.16: A Project Team
Keys to Success as a System Developer
Fig 1.15: The Communication Chain
Keys to Success as a System Developer
Knowledge
• Computer literacy
• Business fundamentals
• Systems theory
• Information use in problem solving
• The systems development process
• Systems modeling
Keys to Success as a System Developer
Skills
• Communications
• Analytical ability
• Creativity
• Leadership
Functions/Components Matrix
Information system components (resources)
• People (information specialists, users)
• Data
• Information
• Software
• Hardware
Information system functions
• Input
• Processing
• Output
• Storage
• Control
Functions/Components Matrix
Fig 1.17 A Functions/Components Matrix with Selected Entries