Systems Analysis & Design 7 th Edition Chapter 10.

Systems Analysis & Design

7th Edition

Chapter 10

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Phase Description

Systems Implementation is the fourth of five phases in the systems development life cycle (SDLC)

Includes application development, testing, documentation, training, data conversion, system changeover, and post-implementation evaluation of the results

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Chapter Objectives

Explain the importance of software quality assurance and software engineering

Describe the application development process Draw a structure chart showing top-down

design, modular design, cohesion, and coupling Explain the coding process

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Chapter Objectives

Explain unit testing, integration testing, and system testing

Differentiate between program, system, operations, and user documentation

List the main steps in system installation and evaluation

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Chapter Objectives

Develop an overall training plan with specific objectives for each group of participants, compare in-house and outside training providers, and describe effective training techniques

Describe the data conversion and changeover methods

Identify and describe changeover methods Explain post-implementation evaluation and

the final report to management

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Introduction

The system design specification serves as a blueprint for constructing the new system

The initial task is application development Before a changeover can occur, the system must

be tested and documented carefully, users must be trained, and existing data must be converted

A formal evaluation of the results takes place as part of a final report to management

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Software Quality Assurance

Software Engineering

– Is a software development process that stress solid design, accurate documentation, and careful testing.

– Software engineering Institution (SEI)designed a set of software development standard called Capability Maturity Model (CMM)

– The purpose was to insure quality, reduce development time, and cut costs.

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Software Engineering

– More recent model is, Capability Maturity Model Integration (CMMI) that integrates software and systems development into a much larger framework called Process Improvement

– CMMI tracks an organization's processes, using five maturity layers

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International Organization for Standardization (ISO)

– Many firms seek assurance that software systems will meet rigid quality standards

– In 1991, ISO established a set of guidelines called ISO 9000-3

– ISO requires a specific development plan

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Overview of Application Development

Objective is to translate the logical design into program and code modules that will function properly

Creation of the System Design

– The tasks involved in system design produced an overall design and a plan for physical implementation

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Application Development Steps

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Project Management

– Even a modest-sized project might have hundreds or even thousands of modules

– Important to set realistic schedules, meet project deadlines, control costs, and maintain quality

– Should use project management tools and techniques

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Structured Application Development

Top-down approach – Proceed from general design to a detailed structure

Partitioning– Is a process that Breaks the system down into

subsystems and modules. It is also called Modular design

Structure Charts

– Structure charts show the program modules and the relationships among them. Higher level module called Control module and lower level called Subordinate modules

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Structure Charts

– Structure charts show the program modules and the relationships among them. Higher level module called Control module and lower level called Subordinate modules

– Modules are reusable codes and can be invoked from more than one points of the chart.

– Data couple shows data that one module passes to another

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Structure Charts

– Control CoupleShows a message or

flag which one module

sends to another to signal

specific condition or action

to another module.

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Structure Charts

– Condition

– Loop

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Cohesion and Coupling

– Cohesion measures a module’s scope and processing characteristics.

– A module that performs a single function or task has higher degree of cohesion which is desirable.

– Coupling describes the relationships and interdependence among modules. The ones that are independent are loosely coupled

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Cohesion and Coupling

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Drawing a Structure Chart– Step 1: Review the DFDs

• Review all DFDs for accuracy and completeness

– Step 2: Identify Modules and Relationships• Transform functional primitives or object methods

into program modules

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Steps in Drawing a Structure Chart

– Step 3: Add Couples, Loops, and Conditions• Identify the data elements that pass from one module

to another

– Step 4: Analyze the Structure Chart and the Data Dictionary

• Ensure that the chart reflects all previous documentation and that the logic is correct

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Other Structured Development Tools

– Program Flowcharts

– Pseudocode

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Object-Oriented Application Development

Object-oriented development (OOD) Object-Oriented Application Development

Compared to Structured Development

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Object-Oriented Application Development

Implementation of Object-Oriented Design

– Programmer makes necessary revisions and updates to class diagrams, sequence diagrams, state transition diagrams, and activity diagrams

– Main objective is to translate object methods into program code modules and determine what event or message will trigger the execution of each module

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Coding

Coding Programming Environments

– Each IT departments has its own programming environment and standards

– Integrated development environment (IDE) like .NET

Generating Code

– Can generate editable program code directly from macros, keystrokes, or mouse actions

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Testing the System

After coding, a programmer must test each program to make sure that it functions correctly

Syntax errors Desk checking: review program for logical error

Logic errors Structured walkthrough, or code review Design walkthrough

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Testing the System

Unit Testing

– Test data

– Programmers must test programs that interact with other programs and files individually

– Stub testing

– Regardless of who creates the test plan, the project manager or a designated analyst also reviews the final test results

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Testing the System

Integration Testing

– Integration testing, or link testing

– Testing the programs independently does not guarantee that the data passed between them is correct

– A testing sequence should not move to the integration stage unless it has performed properly in all unit tests

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Testing the System

System Testing

– Acceptance tests

– You should regard thorough testing as a cost-effective means of providing a quality product

– If conflicting views exist, management will decide whether or not to install the system after a full discussion of the options

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Documentation

Documentation Program

Documentation System Documentation Operations

Documentation User Documentation

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Management Approval

After system testing is complete, you present the results to management

If system testing produced no technical, economical, or operational problems, management determines a schedule for system installation and evaluation

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System Installation and Evaluation

Remaining steps in systems implementation:– Prepare a separate operational and test environment

– Provide training for users, managers, and IT staff

– Perform data conversion and system changeover

– Carry out post-implementation evaluation of the system

– Present a final report to management

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Operational and Test Environments

The environment for the actual system operation is called the operational environment or production environment

The environment that analysts and programmers use to develop and maintain programs is called the test environment

A separate test environment is necessary to maintain system security and integrity and protect the operational environment

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Training

Training Plan

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Training

Vendor Training– If the system includes the purchase of

software or hardware, then vendor-supplied training is one of the features you should investigate in the RFPs (requests for proposal) and RFQs (requests for quotation) that you send to potential vendors

– Often gives the best return on your training dollars

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Training

Webinars and Podcasts

– Webcast is one way transmission, whenever the user wants or needs training supports

– Subscribers can use training anywhere and any time

– As technology continues to advance, other wireless devices such as PDAs and cell phones will be able to receive podcasts

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Training

Outside Training Resources

– Many training consultants, institutes, and firms are available that provide either standardized or customized training packages

– You can contact a training provider and obtain references from clients

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Training

In-House Training

– When developing a training program, you should keep the following guidelines in mind:

• Train people in groups

• Select the most effective place to conduct the training

• Provide for learning by hearing, seeing, and doing

• Prepare effective training materials

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Training

• Tutorial

• Rely on previous trainees

• Train-the-trainer strategy

– Simulation

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Data Conversion

Data Conversion Strategies

– The old system might be capable of exporting data in an acceptable format for the new system or in a standard format such as ASCII or ODBC

– If a standard format is not available, you must develop a program to extract the data and convert it

– Often requires additional data items, which might require manual entry

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Data Conversion

Data Conversion Security and Controls

– You must ensure that all system control measures are in place and operational to protect data from unauthorized access and to help prevent erroneous input

– Some errors will occur

– It is essential that the new system be loaded with accurate, error-free data

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System Changeover

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System Changeover

Direct Cutover

– Involves more risk than other changeover methods

– Companies often choose the direct cutover method for implementing commercial software packages

– Cyclical information systems usually are converted using the direct cutover method at the beginning of a quarter, calendar year, or fiscal year

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System Changeover

Parallel Operation– Easier to verify that the new system is working

properly under parallel operation than under direct cutover

– Running both systems might place a burden on the operating environment and cause processing delay

– Is not practical if the old and new systems are incompatible technically

– Also is inappropriate when the two systems perform different functions

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System Changeover

Pilot Operation– The group that uses the new system first is

called the pilot site– The old system continues to operate for the

entire organization– After they system proves successful at the pilot

site, it is implemented in the rest of the organization, usually using the direct cutover method

– Is a combination of parallel operation and direct cutover methods

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System Changeover

Phased Operation

– You give a part of the system to all users

– The risk of errors or failures is limited to the implemented module only

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Post-Implementation Tasks

Post-Implementation Evaluation– Includes feedback for the following areas:

• Accuracy, completeness, and timeliness of information system output

• User satisfaction• System reliability and maintainability• Adequacy of system controls and security

measures• Hardware efficiency and platform performance

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• Effectiveness of data base implementation

• Performance of the IT team

• Completeness and quality of documentation

• Quality and effectiveness of training

• Accuracy of cost-benefit estimates and development schedules

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Post-Implementation Evaluation

– When evaluating a system, you should:• Interview members of management and key

users

• Observe users and computer operations personnel actually working with the new information system

• Read all documentation and training materials

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• Examine all source documents, output reports, and screen displays

• Use questionnaires to gather information and opinions form a large number of users

• Analyze maintenance and help desk logs

– Whenever possible, people who were not directly involved in developing the system should conduct the post-implementation evaluation

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Final Report to Management

– Your report should include the following:• Final versions of all system documentation

• Planned modifications and enhancements to the system that have been identified

• Recap of all systems development costs and schedules

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• Comparison of actual costs and schedules to the original estimates

• Post-implementation evaluation, if it has been performed

– Marks the end of systems development work

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Chapter Summary

The systems implementation phase consists of application development, testing, installation, and evaluation of the new system

Analysts and technical writers also prepare operations documentation and user documentation

Develop a training program

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Chapter Summary

Data conversion often is necessary when installing a new information system

System changeover is the process of putting the new system into operation

A post-implementation evaluation assesses and reports on the quality of the new system and the work done by the project team

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Chapter Summary

The final report to management includes the final system documentation, describes any future system enhancements that already have been identified, and details the project costs

The report represents the end of the development effort and the beginning of the new system’s operational life

Chapter 10 complete

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Systems Analysis & Design 7 th Edition Chapter 10.

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