Slide 10-1 Chapter 10 Systems Development Procedures Introduction to Information Systems Judith C. Simon

Slide 10-2 "Copyright © 2001 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Copyright Act without the express written permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein."

Slide 10-3 Chapter 10 Major Topics ä Felt or identified need ä Initial investigation ä Requirements determination ä System design ä System implementation ä System maintenance ä Trends in systems development

Slide 10-4 Overview Stages of system development range from an initial need that is identified through the entire process of developing and then maintaining a system. A system development project can be stopped at any time that it is no longer determined to be feasible. The development phases that occur may be repeated as often as needed or combined with other phases, so these steps or phases are not necessarily sequential.

Slide 10-5 System Development Phases* (*not entirely a sequential process) FeltNeed InitialInvestigation RequirementsDetermination SystemDesign SystemImplementation System Maintenanc e

Slide 10-6 Phase 1: Felt (or Identified) Need ä A system development project begins when someone identifies that a need exists for a change ä Project proposals may be suggested by a current system user, a top executive, a customer, etc. - anyone with some knowledge of system needs ä A proposal usually includes a description of the problem, explanation of its importance, potential solutions, and sources of additional information

Slide 10-7 Phase 2: Initial Investigation Two major aspects: ä defining the exact problem or situation, which involves gathering adequate information and continuing to refine the definition through several iterations ä conducting a feasibility study to see if the project appears to be appropriate for the organization to pursue (feasibility continues to be monitored throughout the project phases)

Slide 10-8 Typical Feasibility Factors ä Financial/economic: What costs and benefits are involved? ä Technical: Is the needed technology available? ä Schedule: Can the project be developed within a reasonable time? ä Operational: Will the system be usable by current personnel and with current systems? ä Motivational: Will current personnel be willing to support the new system? ä Legal/ethical: Is the system legal and ethical?

Slide 10-9 Phase 3: Requirements Determination Two major activities: ä Study of existing system, based on input from current users and on existing documents (e.g., procedures manuals and reports; often uses data flow diagrams (DFDs) and entity-relationship (E-R) diagrams ä Determination of user requirements and constraints, based on information gathered about the existing system; prototyping is sometimes used to identify requirements or constraints (restrictions or problems that must be considered)

Slide Data Flow Diagram (DFD) Graphical tool used in various phases of system development to analyze the flow of data in a form that is easy to use and to understand

Slide Data Flow Diagram Symbols Data Flow Process Data Source/ Sink Data Store

Slide Entity-Relationship (E-R) Diagram ä Graphical tool that shows relationships among various entities ä Entity: Something of interest to the organization (a person, place, or thing about which the organization wants to keep data)

Slide Entity-Relationship Diagram CustomerOrder CustomerOrder Customer # Name Name Address Address 1 Order # Date Date M

Slide Prototyping ä A tool that can be used in various system development phases, involving the development of a small working model of some part or all of a system so that results can be reviewed

Slide Phase 4: System Design ä Uses results of requirements determination phase to design the new system, starting with a logical design, which becomes the basis for the physical design ä Logical design: indicates how the components will work together through all activities that will occur, with specific consideration given to system components (hardware, software, data, people, procedures) ä Physical design: involves actual specific design of all components of the system, based on logical design

Slide Flow of System Design Define physical design Define logical design THEN People Procedure s Hardware Software Data

Slide Phase 5: System Implementation ä Involves determining sources for all components as well as actual acquisition and installation

Slide Hardware Acquisition Considerations ä Will new hardware be compatible with existing hardware? ä Where should the hardware be purchased? ä If multiple sources are used, will coordination and compatibility be an extensive problem? ä Is equipment available for delivery in a reasonable time? ä What guarantees and warranties are available? ä What types of support are provided by the hardware supplier? ä Will employee training be needed; who will supply it?

Slide Typical Sources of Hardware ä Manufacturers and other large suppliers ä Computer dealers ä Mail order companies

Slide Software Acquisition Considerations ä What software is currently available that fits the organization’s needs? At what cost? ä Is this software compatible with current systems? ä How much time will be required for obtaining this software? ä Does the vendor provide a guarantee, a warranty, user training, etc.? ä Can the software be altered to fit specific needs? ä Where should remaining programs be developed-- externally, internally, or some of both?

Slide System Installation ä System installation considerations include getting the physical space prepared, getting all hardware and software installed, converting data files into whatever format is required for the new system, training the system users, actually converting to the new system, and testing it.

Slide Preparation for System Installation Preparation for System Installation Prepare Site Prepare Hardware Prepare Software Prepare Data Prepare System Users

Slide Implementation System Implementation Acquisition of hardware and software Preparation for system installation Conversion to new system

Slide System Conversion Options ä Parallel: Old system is retained until new system runs properly ä Piecemeal: New system slowly replaces old system, often replacing only one part of the old system at a time ä Pilot: New system is tried first with small test group, such as one department ä Plunge (“direct cutover”): Change occurs all at once from old to new system

Slide Phase 6: System Maintenance ä Involves making changes to the system as needed; two primary parts: ä Regular review of system to ensure that it is meeting the needs of the organization ä Making changes that are needed to meet current needs and to remain competitive or improve the competitive position ä Usually a large part of the overall cost of a system, partly because businesses want to keep the system running for several years

Slide System Development Trends ä Rapid application development (RAD) tools: assist in development of system components so that these basic parts can be developed more quickly ä Internet/intranet development: process is similar to standard procedures, but those developing Internet sites must consider perceptions of outsiders; those developing intranet sites must be concerned with human factors involved in such a change, as well as technological considerations

Slide System Development Trends, continued ä Business process reengineering: emphasizes radical redesigns of business processes, perhaps for the entire organization; use of this philosophy has decreased in recent years ä Total quality management: attempt to eliminate errors to try to reduce costs and improve customer service; use of this concept continues but has decreased in recent years ä Benchmarking: compares a business’ activities to those of the best companies doing similar work; this concept has increased in use in recent years

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