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System Implementation

Gary B. Shelly, Thomas J. Cashman, and Harry J. Rosenblatt. 2007. Systems Analysis and Design. 7th Ed. Course Technology.

ดร. สลิล บุญพราหมณสํานักวิชาสารสนเทศศาสตร

MIT- 534 Systems Analysis and Design

Lecture 8

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Software Quality Assurance

• Quality assurance

• Software Engineering

Software Engineering Institute (SEI)

Capability Maturity Model (CMM)

Capability Maturity Model Integration (CMMI)

Process improvement

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

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Overview of Application Development

• 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

Module

Start by reviewing documentation from prior SDLC phases and creating a set of program designs

After the design is created, coding can begin

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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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การเขียนโปรแกรม

• เปนการแปลง logic ทีอ่อกแบบโดยใช Diagram ตางๆเพื่อเขยีนโดยใชภาษาสั่งงาน (Programming language)

• โดยทั่วไปการเขียนควรใช format มาตรฐานเพื่อทําใหการดูแลโปรแกรมทําไดงาย

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Structured Application Development

• Top-down approach

• Partitioning

• Modular design

• Must proceed carefully, with constant input from programmers and IT management to achieve a sound, well-integrated structure

• Must ensure that integration capability is built into each design and thoroughly tested

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Structure Charts

Structure charts show the program modules and the relationships among them

Control module

Subordinate modules

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Module

Library module

Data Couple

Control Couple

Flag

A module uses a flag to signal a specific condition or action to another module

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Structure Charts

Condition

A condition line indicates that a control module determines which subordinate modules will be invoked, depending on a specific condition

Loop

A loop indicates that one or more modules are repeated

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Cohesion and Coupling

If you need to make a module more cohesive, you can split it into separate units, each of which performs a single function

Loosely coupled

Tightly coupled

Status flag

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Structure Chart Examples

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Drawing a Structure Chart

Step 1: Review the DFDs

Step 2: Identify Modules and Relationships

Step 3: Add Couples, Loops, and Conditions

Step 4: Analyze the Structure Chart and the Data Dictionary

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Other Structured Development Tools

Program Flowcharts

Pseudocode

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Coding

• Programming Environments

Each IT department has its own programming environment and standards

Integrated development environments (IDEs)

• Generating Code

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

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Testing

• Syntax errors

• Desk checking

Logic errors

• Structured walkthrough, or code review

• Design walkthrough

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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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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

Major objectives:

Perform a final test of all programs

Verify that the system will handle all input data properly, both valid and invalid

Ensure that the IT staff has the documentation and instructions needed to operate the system properly and that backup and restart capabilities of the system are adequate

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Demonstrate that users can interact with the system successfully

Verify that all system components are integrated properly and that actual processing situations will be handled correctly

Confirm that the information system can handle predicted volumes of data in a timely and efficient manner

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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

• Program Documentation

• System Documentation

• Operations Documentation

• User Documentation

Online 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

The first step is to identify who should receive training and what training is needed

The three main groups for training are users, managers, and IT staff

You must determine how the company will provide training

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Train people in groups, with separate training programs for distinct groups

Select the most effective place to conduct the training

Provide for learning by hearing, seeing, and doing

Prepare effective training materials, including interactive tutorials

Tutorial

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Vendor Training

If the system includes the purchase of software or hardware, then vendor-supplied training is one of the features you should include 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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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

Center for the Application of Information Technologies (CAIT)

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In-House Training

The IT staff and user departments often share responsibility

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

Rely on previous trainees

Train-the-trainer strategy

When Training is complete, many organizations conduct a full-scale test, or simulation

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Data Conversion

Data Conversion Strategies

The old system might be capable of exportingdata 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 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

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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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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Direct and Parallel installation

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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 the 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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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

Is less expensive than full parallel operation

Is not possible, however, if the system cannot be separated easily into logical modules or segments

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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

Effectiveness of database implementation

Performance of the IT team

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Completeness and quality of documentation

Quality and effectiveness of training

Accuracy of cost-benefit estimates and development schedules

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Post-Implementation Tasks

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

Examine all source documents, output reports, and screen displays

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

Analyze maintenance and help desk logs

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Post-Implementation Evaluation

Users can forget details of the developmental effort if too much time elapses

Pressure to finish the project sooner usually results in an earlier evaluation in order to allow the IT department to move on to other tasks

Ideally, conducting a post-implementation evaluation should be standard practice for all information systems projects

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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

A 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

Final Report to Management