Chapter 12 Systems Development The Strategic Management of Information Technology

Transaction Processing System Input Output Process Information Communication Systems Development

Systems Development Life Cycle Consists Of Six Phases l Systems Planning l Systems Analysis l General Systems Design l Systems Evaluation and Selection l Detailed Systems Design l Systems Implementation

3 Categories of Systems Design l Global-Based Systems l Group-Based Systems l Local-Based Systems

Global-Based Systems l Large, Complex Information Systems that Process High Transaction Volumes l Complete Overhaul or Replacement of Systems Design Components – Old output is changed from monthly tabular reports to online screen displays – New processes are developed – Input captured by scanning devices – Old hierarchical database is converted to new relational database with standard query language – Controls are installed – New technology platform composed of enterprise-wide network topology supports systems design components

Group-Based Systems l Serve a Single Department or other specific group of users – smaller than, connected to global-based system

Local-Based Systems l Concentration on Local Environment

Rapid Application Development l Joint Application Development (JAD) l Specialists with Advanced Tools (SWAT) l Computer-Aided Systems and Software Engineering (CASE Tools) l Prototyping

Design Approaches l Process-Oriented Approach l Data-Oriented Approach l Object-Oriented Approach

Design Principles l Modularity – Maintainability – Reusability l Libraries of object class catalogs – Reliability – Extendibility – Standardized – Independence – Variety in Use – Top-Down Design l Start with Abstract Description of New System l Refine View in Successive Steps – Bottom-Up Design l Start with Objects and Assemble them to completed product

Process-Oriented Approach l Based upon Stable Set of Input, Process, and Output l Transactions-Based Applications – Accounts Payable – Accounts Receivable – Payroll – Inventory Control

Data-Oriented Approach l Undefined Systems Processes l Define All Needed Data Attributes l Systems Analysts must determine, with users, how the system will be used

Data-Oriented Approach: Steps l Discuss potential decisions that will be made from system with users of system – Model the purchasing decision support system through use of flexible modeling tool l Product Quality l Past Performance l Product Availability – Divide Each Criterion into Attributes – Develop Data Dictionary l Size, Type, Description, Limits and Exceptions, Ranges, Security Level, Access Privileges l Changes, Description, Order

Object-Oriented Approach l Catalog objects – Found by keywords – In a Library or Database l Objects – Exhibit certain behaviors – Attributes and operations are encapsulated or pulled together – Operations describes how attributes are processed – Behave in certain ways in response to messages

Object-Oriented Approach l Classes – Set of Objects that share common structure and behavior l Inheritance – Objects receive attributes and operations from other objects – Add more attributes and operations of their own l Polymorphism – Ability of object to respond to and implement each object

Object-Oriented Steps l Identify Object Class l Identify Relationships l Identify Attributes l Determine Inheritance Relationships l Build Class Hierarchy – Order – Transaction Process – Tools Inventory

Joint Application Development l Conceptual Systems Design Model – Data Flow Diagram – Entity Relationship Diagram – Decision Table – Screen Prototype – Decision Tree

SDLC Strengths l Provide Control over Development Process l Formality

SDLC Weaknesses l Increased Cost of Development l Lengthened Development Time l Difficult when Project is Hard to Define

End-User Development l Users Develop the Prototypes l Fourth-Generation Languages l CASE Tools

Steps Toward Integration l Windowing Operating System – OS/2 Presentation Manager – Windows – X-Windows (Sun) l Transaction Processing Systems – Payroll Services – Sales Order Processing Systems – Process Control Systems – Corporate Accounting Systems

Steps Toward Integration l Multi-Tasking – Allow Users to run different programs at the same time – Windows – OS/2 (Presentation Manager) – XWindows l Networks – Enable Dynamic Integration from Several Sources

Integration l Vertical – Different Levels of Production – ex: Oil Company l Horizontal – Retail Stores – ex:Wal-Mart

Object-Orientation l Different than Transmitting Raw Bits of Data – Hardware Connections – Access Controls – Simple Data Formats l Software Agents – object-oriented programs written to perform specific tasks in response to user requests – agents know how to exchange object attributes – agents have the ability to activate object functions in other agents l Multimedia – Integration of Text, Video, Sound, Pictures, Animation

Integration/Links l Static – Hard-Coded – Import l Dynamic – Linked – Dynamic Data Exchange (DDE) – Hot-Linked – Object-Linking and Embedding (OLE) l Original Software Package Automatically started when chosen

Systems Project Proposals l Feasibility Factors – Technical – Economic – Legal – Operational – Schedule l Strategic Factors – Productivity – Differentiation – Management

Systems Plan l Business Plan – Document Company’s Goals and Objectives – Align Systems Project with Company’s Business Plan l Enterprise-Wide Model – Entity Relationship Diagram showing relationship between organization’s entities and their relationship to supporting strategies of Business Plan – View of Future Organization of Enterprise under a Business Plan

Two Levels of Planning l Systems Planning – Gives Managers, Users, and Information Systems Personnel Projects – Establishes what should be done – Sets a budget for the total cost of these projects l Systems Project Planning – Setting a plan for the development of each specific systems project

Systems Professional Skills l Systems Planning – Form project team after proposed systems project is cleared for development l Systems Analysis – Business Systems Analysts knowledgeable in business l General Systems Design – Business Systems Analysts l Systems Evaluation and Selection – Business Systems Analysts l Detailed Systems Design – Wide Range of Systems and Technical Designers l Systems Implementation – Systems analysts, programmers, and special technicians

Effective Leadership Style l Autocratic Style – Crisis-Style Management – Used to Correct Major Problem, such as Schedule Slippage l Democratic Style – Team-oriented Leadership – Gives each team member the freedom to achieve goals which he/she helped set l Laissez-Faire Style – Highly-motivated, Highly-Skilled Team Members – People who work best alone

Project Management Skills l Planning – States what should be done – Estimates how long it will take – Estimates what it will cost l Leading – Adapts to dynamics of enterprise and deals with setbacks – Guides and induces people to perform at maximum abilities l Controlling – Monitors Progress Reports and Documented Deliverables – Compares Plans with Actuals l Organizing – Staffs a Systems Project Team – Brings together users, managers, and team members

CASE l Computer-Aided Systems and Software Engineering l Increase Productivity of Systems Professionals l Improve the Quality of Systems Produced l Improve Software Maintenance Issue l Includes: – workstations – central repository – numerous modeling tools – project management – Systems Development Life Cycle Support – Prototyping Applications – Software Design Features

Central Repository l Models Derived from Modeling Tools l Project Management Elements l Documented Deliverables l Screen Prototypes and Report Designs l Software Code from Automatic Code Generator l Module and Object Libraries of Reusable Code l Reverse Engineering, Reengineering, and Restructuring Features

Software Maintenance l Reverse Engineering – Extract original design from spaghetti-like, undocumented code to make maintenance change request – Abstract meaningful design specifications that can be used by maintenance programmers to perform maintenance tasks l Reengineering – Examination and changing of a system to reconstitute it in form and functionality – Reimplementation l Restructuring – Restructures code into standard control constructs l sequence, selection, repetition

Work Group Technologies l Suite of Products l GroupWare

Examples of Suite of Products l Microsoft Corporation – Word – Excel – PowerPoint l Lotus Development Corporation – AmiPro – Lotus – Freelance l Novell/Borland – WordPerfect – Borland – dBaseIV

Advantages of Suite of Products l Integrated Document l Economies of Scale l Consolidated Training l Shared Files Across Group

Disadvantages of Suite of Products l Choice Based upon Group Rather than Advantages of Individual Product l “Locked In” to Product Company l Difficulty in Matching Client Requirements

Today’s Organization l Enterprise-Wide Development l Object-Oriented Definition l Implementation of Suite Approach

Unsuccessful Systems l Systems were developed which did not support business strategies and objectives. l Poor systems planning and inadequate project management. l Failure to define or understand user requirements. l Negligence in estimating costs and benefits of the systems project. l Creation of a myriad of design defects and errors. l Acquisition of computers and software that no one needs or knows how to use. l Installation of incompatible or inadequate technology. l Negligence in implementing adequate controls. l Development of unstructured, unmaintainable software. l Inadequate implementation tasks.

PDM l Productivity l Differentiation l Management

Project Management l Gantt Chart l Pert Chart

Gantt Chart l Compares Planned Performance against actual performance to determine whether the project is ahead of, behind, or on schedule l Schedule a complete systems project by phases

PERT Chart l Estimate, Schedule, and Control a network of interdependent tasks l Shown by arrows, nodes, or circles l Program, Evaluation and Renew Technique l Determine minimum time needed to complete a project, phase, or task l Critical Path – Minimum time needed to complete a project or phase – Total of the most time-consuming chain of events l Four Steps – Identify Tasks – Determine Proper Sequence of Tasks – Estimate the Time Required to Perform each Task – Prepare Time-Scaled Chart of Tasks and Events to Determine the Critical Path