Chapter 10: Systems Development

Succeeding with Technology: Second Edition

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Objectives

Describe the systems development life cycle, who participates in it, and why it is important

Discuss systems development tools

Understand how systems development projects are investigated

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Objectives (continued)

Describe how an existing system can be evaluated

Discuss what is involved in planning a new system

List the steps to implement a new or modified system

Describe the importance of updating and monitoring a system

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An Overview of Systems Development

Systems development process Typically called a systems development life cycle

(SDLC) Systems investigation and analysis

Looks at the existing system and determines if it can and should be improved

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An Overview of Systems Development (continued)

Systems design and implementation Modifying an existing system or developing a new

one Maintenance and review

Makes sure that the new or modified system is operating as intended

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Participants in Systems Development System stakeholders

Individuals who will benefit from systems development project

Users Individuals who will be interacting with the system

on a regular basis Managers

People most capable of initiating and maintaining change

Systems analyst Specializes in analyzing and designing systems

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Why Start a Systems Development Project? Creative analysis

Investigating new approaches to existing problems Critical analysis

Being skeptical and doubtful Questioning whether or not the current computer

system is still effective and efficient Systems development process

Begins with gathering information on users’ needs

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End-User Systems Development The development of computer systems by

Individuals outside of the formal computer systems planning and departmental structure

Systems developed by end users Range from the very small to those of significant

organizational value

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Tools and Techniques for Systems Development

Systems development tools Can greatly simplify the systems development

process Include

Computer-aided software engineering tools Flowcharts, decision tables Project management tools, prototyping, Outsourcing, and object-oriented systems

development

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Computer-Aided Software Engineering

Software engineering Employs computer-aided software engineering

(CASE) tools CASE tools

Automate many systems development tasks Allow more than one person to work on the same

system at the same time via a multiuser interface

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Flowcharts

Reveal the path from a starting point to the final destination

Can display various amounts of detail When developing a system

General flowchart describes the overall purpose and structure of the system

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Decision Tables

Can be used as an alternative to or in conjunction with flowcharts

In general, a decision table displays The various conditions that could exist The different actions that the computer should take

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Project Management Tools

Purpose is to plan, monitor, and control necessary development activities

Program Evaluation and Review Technique (PERT) Creates three time estimates for an activity

The shortest possible time The most likely time The longest possible time

Gantt charting A grid that lists activities and deadlines

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Prototyping

The creation of a preliminary model or version of a major subsystem

Iterative approach to systems development Each phase of the SDLC is repeated several times

(iterated)

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Outsourcing

Use of outside company to take over portions of its workload

Guidelines to make outsourcing a success Keep tight controls on the outsourcing project. Treat outsourcing companies as partners Start with smaller outsourcing job Create effective communications channels between

the organization and the outsourcing company

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Object-Oriented Systems Development An extension of object-oriented programming Can be used during all phases of systems

development Organizations

Have saved time and money using the object-oriented approach to systems development

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Systems Investigation

Overall purpose Determine whether objectives of existing system

satisfy the goals of the organization Attempts to answer the following questions

What primary problems might a new or enhanced system solve?

What opportunities might a new or enhanced system provide?

What are the potential costs? What are the associated risks?

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Feasibility Analysis Technical feasibility

Concerned with whether or not hardware/software can be acquired or developed to solve the problem

Economic feasibility Determines if the project makes financial sense

Legal feasibility Determines whether laws or regulations may

prevent or limit a systems development project

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Feasibility Analysis (continued) Operational feasibility

Measure of whether or not the project can be put into action or operation

Schedule feasibility Determines if the project can be completed in a

reasonable amount of time

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Systems Analysis

Attempts to understand how the existing system helps solve the problem identified in systems investigation

Overall emphasis To gather data on the existing system and the

requirements for the new system To consider alternative solutions to the problem and

the feasibility of the solutions

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General Analysis Considerations Formalized analysis procedure involves

Collecting appropriate data Analyzing the data Determining new system requirements and project

priorities

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Collecting Data

Purpose To seek additional information about problems

identified during systems investigation Techniques

Interviews Direct observation Outputs Questionnaires Other Data Collection Methods

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Requirements Analysis

Purpose To determine user, stakeholder, and organizational

needs Tools and techniques

Asking Directly Critical Success Factors Joint Application Development Rapid Application Development

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Systems Design

Overall purpose To select and plan a system that meets the

requirements needed to deliver the problem solution Results

A new or modified system

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Generating Systems Design Alternatives First step of design

Investigate alternatives for all components Request for information (RFI)

Asks a computer systems vendor to provide information about its products or services

Request for quotes (RFQ) Asks a computer systems company to give prices

for its products or services Request for proposal (RFP)

Generated during systems development

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Systems Implementation

Includes Hardware acquisition Software acquisition or development User preparation Hiring and training of personnel Site and data preparation Installation, testing, startup, and user acceptance

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Acquiring Hardware

Most people and organizations acquire hardware and computers by Purchasing, leasing, or renting computer resources

from a computer systems vendor “Pay as you go computing”

Organization pays only for the computer power it uses

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Selecting and Acquiring Software:Make, Buy, or Rent Program specification

Description of what the software must accomplish Algorithm

Step-by-step sequence of computer instructions Syntax errors

Errors in the use of the programming language syntax

Logic errors Errors in the programming logic

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Acquiring Database and Telecommunications Systems A database is one of the most important parts of

system development Many projects involve a database May require both hardware and software acquisition

Telecommunications is one of the fastest growing business applications May require both hardware and software acquisition

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User Preparation

Readying users and stakeholders for the new or modified system

Can include Marketing Training Documentation Support

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Site Preparation

Location of the new system needs to be prepared For a small system

May mean rearranging the furniture Larger systems

May require special wiring and air conditioning

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Data Preparation

Converting manual files into computer files Data conversion

May be required to transform the existing computerized files into the proper format

Permanent data Must be placed on a permanent storage device

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Installation

Placing computer equipment on the site and making it operational

For a small systems development project May require making room on top of a desk for a new

PC Plugging it into a wall outlet Following the manufacturer’s instructions to turn it

on

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Testing

Unit testing Developing test data that will force the computer to

execute every statement in the program System testing

Requires the testing of all programs together Volume testing

Ensures that entire system can handle a large amount of data under normal operating conditions

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Testing (continued)

Integration testing Ensures that new programs can interact with other

major applications Acceptance testing

Ensures that new or modified system is operating as intended

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Startup

Direct conversion Stopping the old system and starting the new one

on a given date Phase-in approach

New system is slowly phased in, while old one is slowly phased out

Pilot startup Running a pilot or small version of the new system

along with the old

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User Acceptance and Documentation

User acceptance document Agreement signed by user that a phase of the

complete system is approved Documentation

Includes all materials that describe the new or modified system

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User Acceptance and Documentation (continued)

Systems documentation Describes the technical aspects of the new or

modified system User documentation

Describes how the system can be used by noncomputer personnel

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Systems Maintenance and Review

Final steps of systems development Involves checking, changing, and enhancing the

system

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Reasons for Maintenance

New requests from stakeholders, users, and managers

Bugs or errors in the program Technical and hardware problems Corporate mergers and acquisitions Governmental regulations that require changes in

programs

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The Financial Implications of Maintenance

For older programs Cost of maintenance can be up to five times greater

than cost of development Average programmer

Can spend from 50% - over 75% of his/her time maintaining programs

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Systems Review

Final phase of the systems development life cycle Analyzing systems to make sure that they are

operating as intended Two types of review procedures

Event-driven review Time-driven review

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Summary

Phases of the SDLC Investigation, analysis, design

Implementation, maintenance, review Common system development tools and techniques

CASE tools Flowcharts Decision tables

Systems investigation First step in the development of a new or modified

computer system

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Summary (continued) Systems analysis

The examination of existing systems Systems design

Prepares detailed design needs for new system or modifications to the existing one

Systems implementation Includes hardware acquisition, software acquisition

or development, and user preparation Systems maintenance

Involves checking, changing, and enhancing the system