1. Chapter 1 The Systems Development Environment
Essentials of Systems Analysis and Design Fifth Edition Joseph S. Valacich Joey F. George Jeffrey A. Hoffer
Chapter 1
The Systems Development Environment
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Learning Objectives
Define information systems analysis and design
Discuss the modern approach to SAD that combines process and data views
Describe the role of the systems analyst
Describe the SDLC and alternatives
Describe role of computer aided software engineering (CASE) tools
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3. What is Information Systems Analysis and Design?
A method used to create and maintain systems that perform basic business functions
Main goal - to improve employee efficiency by applying software solutions to key business tasks
A structured approach to ensure success
Systems Analysts perform SAD based upon:
Understanding of organization’s objectives, structure and processes
Knowledge of how to exploit information technology for advantage
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5. Systems Analysis and Design: Core Concepts
Major goal: to improve organizational systems by developing or acquiring application software and training employees in its use
System: Turns data into information and includes:
Hardware and system software
Documentation and training materials
Job roles associated with the system
Controls to prevent theft or fraud
The people who use the software to perform their jobs
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Systems Analysis and Design: Core Concepts
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Software Engineering Process
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System
A system is an interrelated set of business procedures used within one business unit working together for a purpose
A system exists within an environment
A boundary separates a system from its environment
A system has nine characteristics
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Characteristics of a System
Purpose
Environment
Boundary
Components
Interrelationships
Constraints
Interfaces
Input
Output
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10. Important System Concepts
Decomposition
The process of breaking down a system into smaller components
Allows the systems analyst to:
Break a system into small, manageable and understandable subsystems
Focus on one area at a time, without interference from other areas
Concentrate on component pertinent to one group of users without confusing users with unnecessary details
Build different components at independent times and have the help of different analysts
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11. Important System Concepts
Modularity
Process of dividing a system into modules of a relatively uniform size
Modules simplify system design
Coupling
Subsystems that are dependent upon each other are coupled
Desired: loose coupling
Cohesion
Extent to which a subsystem performs a single function
Desired: high cohesion
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12. Cohesion and Coupling  
Effective modularization = max. cohesion within modules
+ min. coupling between modules
component 1 2 3 4
component
Bridge 5 6
High cohesion
Low coupling  
Adapted from Software Engineering: An Object-Oriented Perspective by Eric J. Braude (Wiley 2001), with permission.

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Cohesion and Coupling
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14. A Modern Approach to Systems Analysis and Design
Systems Integration
Allows hardware and software from different vendors to work together
Enables procedural language systems to work with visual programming systems
Visual programming environment uses client/server model
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15. SA role in Systems Development
Study problems and needs of an organization
Determine best approach to improving organization through use of:
People
Methods
Information technology
Help system users and managers define their requirements for new or enhanced information systems
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16. Systems Development Methodology … e.g. SDLC
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17. Phases of the Systems Development Life Cycle
1. Systems Planning and Selection
Two Main Activities
Identification of need
Investigation and determination of scope
2. Systems Analysis
Study of current procedures and information systems
Determine requirements
Generate alternative designs
Compare alternatives
Recommend best alternative
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18. Phases of the Systems Development Life Cycle
3. System Design
Logical Design - Business aspects of the system
Physical Design - Technical specifications
System Implementation, Operation and Maintenance
Hardware and software installation
User Training
Documentation
Operations
Maintenance (fix errors, make changes)
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19. Alternative Approaches to Development
Prototyping
Building a scaled-down working version of the system
Advantages:
Users are involved in design
Captures requirements in concrete form
Disadvantages:
Users may misunderstand SD complexity
Code often thrown away
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20. Alternative Approaches to Development
Joint Application Design (JAD)
Users, Managers and Analysts work together for several days
System requirements are reviewed
Structured meetings
Rapid Application Development (RAD)
Utilizes prototyping to delay producing system design until after user requirements are clear
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22. Approaches to Development
Agile Methodologies
Extreme Programming, Adaptive S/W Development, Scrum
Focuses on
Adaptive methodologies
People instead of roles
Self-adaptive development process
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23. Computer-Aided Software Engineering (CASE) Tools
Automated software tools used by systems analysts to develop information systems
Project management tools (Openproj, MS Project)
Diagramming tools (Dia, Visio)
Computer display and report generators (VB)
Analysis tools (Visual Analyst)
Documentation generators
Code generators
Integration of tools via a repository
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24. Information Systems 1.1

25. Meaning Of Information Systems
An information system is an organized combination of people, hardware, software, communications Networks and data resources that collects, transforms, and disseminates information in an organization.

26. MANAGEMENT INFORMATION SYSTEM(MIS)
The MIS is defined as a system based on the database of the evolved for the purpose of providing information to the people in the organization.

27. Information System Components

28. Information System Components
Hardware
Moore’s Law
Software
System software
Application software
Enterprise applications
Horizontal system

29. Information System Components
Software
Vertical system
Legacy systems
Data
Tables
Linking

30. Information System Components
Processes
Define the tasks and business functions that users, managers, and IT staff members perform to achieve specific results
People
Users, or end users, are the people who interact with an information system, both inside and outside the company

31. Contemplative Questions
What are the 4 types of information systems?
How are they different?
Who are the primary users?
How much data is being stored by each?
How much data is being read (queried) by each?
Transaction processing systems automate the handling of data about business activities or transactions.
Management information systems take the information generated by transaction processing systems and convert it into aggregated forms meaningful to managers.
Decision support systems are designed to help organizational decision makers make decisions by providing an interactive environment that uses data and models.
Expert systems represent attempts to codify and manipulate knowledge rather than information by mimicking experts in particular knowledge domains.
TPS: large number of transactions (writes to database), involves/produces small amount of data, used by operatives.
MIS: smaller number of transactions (reads), summaries require larger amounts of data, used by supervisors or managers.
DSS: even smaller number of transactions (large reads/table scans), larger amounts of data, used by analysts and managers.
ES: smaller amount of data, rule-based knowledge, e.g. diagnostic systems, commonly used by operatives.

32. Types of Information Systems

33. Top Managers Middle Managers First-Line Managers Operatives
Exercise. Match the type of information system with the organizational level where they are most commonly used:
Transaction Processing Systems (TPS)
Management Information Systems (MIS)
Decision Support Systems (DSS)
Expert Systems (ES)
Top
Managers
Middle
Managers
First-Line
Managers
Operatives

34. Types of Information Systems and Systems Development
Transaction Processing Systems (TPS)
Automate handling of data about business activities (transactions)
Management Information Systems (MIS)
Converts raw data from transaction processing system into meaningful form
Decision Support Systems (DSS)
Designed to help decision makers
Provides interactive environment for decision making

35. Types of Information Systems and Systems Development
Expert Systems (ES)
Replicates decision making process
Knowledge representation describes the way an expert would approach the problem
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