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 1.1 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 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 1.2 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.6 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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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 1.5 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall Systems Analysis and Design: Core Concepts 1.6 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall Software Engineering Process 1.7 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 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 1.8 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall Characteristics of a System Purpose Environment Boundary Components Interrelationships Constraints Interfaces Input Output 1.9 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.10 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.11 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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.

Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall Cohesion and Coupling 1.13 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.14 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.15 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

Systems Development Methodology … e.g. SDLC 1.16 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.17 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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) 1.18 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.19 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.20 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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Approaches to Development Agile Methodologies Extreme Programming, Adaptive S/W Development, Scrum Focuses on Adaptive methodologies People instead of roles Self-adaptive development process 1.22 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

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 1.23 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

Information Systems 1.1

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.

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.

Information System Components

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

Information System Components Software Vertical system Legacy systems Data Tables Linking

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

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.

Types of Information Systems

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

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

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 1.35