Systems Implementation PHASE 4: SYSTEMS IMPLEMENTATION Chapter 9 Systems Implementation

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

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 and how code is generated Explain unit testing, integration testing, and system testing 3

Chapter Objectives Differentiate between program, system, operations, and user documentation List the main steps in system installation and evaluation 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 3

Chapter Objectives Describe the data conversion process Identify and describe changeover methods Explain post-implementation evaluation Describe the final report to management

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 4

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

Overview of Application Development 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 Building a system requires careful planning After you establish your strategy, individual modules must be designed, coded, tested, and documented. A module consists of related program code organized into small units After the modules are developed and tested individually, you perform more testing (integration and finally system testing), along with documentation of the entire system.

Overview of Application Development 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

Structured Application Development Top-down approach Partitioning Modular design Constant input from programmers/IT management Ensure integration capability Top-Down Design: In top-down design, sometimes called structured design, a systems analyst starts with the big picture and then zooms in on the details, breaking the original set of requirements into smaller, more manageable sections (called partitioning). This approach is called modular design and is similar to constructing a leveled set of DFDs. Programs developed using the top-down approach usually benefit from the simplicity of their design and are reliable and easy to maintain. Note the importance of proceeding 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 Although top-down design is the most popular development method, an alternative approach is bottom-up design, which implements the modules at the bottom of a structure chart first.

Structured Application Development Structure Charts Structure charts show the program modules and the relationships among them Control module Subordinate modules A structure chart, sometimes called a hierarchy chart, shows program modules graphically in a hierarchical arrangement. Figure 9-7, differentiates between a control module and subordinate modules. Control modules control the flow of execution. Subordinate modules are like “worker bees,” containing the program logic to perform the functions.

Structured Application Development Structure Charts Module Library module Data Couple Control Couple Flag Structure Charts Module Library module – reusable code and can be invoked from more than one point in the chart Data Couple – an arrow with an EMPTY circle. Shows data that one module passes to another. A data couple can be an individual data item (such as an account number) or a higher-level data structure (such as a record). Fig. 9-8, pg. 421  Lookup Customer Name module exchanges data with maintain Customer Data module. Control Couple – an arrow with a FILLED circle. Shows a message, aka a flag, which one module sends to another. Fig. 9-9, pg. 421  update Customer File module sends an Account Overdue flag back to maintain Cusomer Data module. A module uses a flag to signal a specific condition or action to another module

Structured Application Development 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 Condition Condition lines indicate that a lower-level module is called only when certain conditions exists. Fig.9-10, pg 421  Sort Inventory parts is a control module with a condition line that triggers one of the three subordinate modules. Loop A loop indicates that one or more modules are repeated Fig. 9-11, pg 422  Get Student Grades and Calculate GPA modules are repeated

Structured Application Development Cohesion and Coupling Highly cohesive Loosely coupled Tightly coupled Status flag Cohesion: It is desirable to have modules that are highly cohesive and loosely coupled. Cohesion assesses the internal strength of a module. It measures the modules ability to perform a single function or task. A cohesive module focuses on a single task and is much easier to code and reuse  therefore, desirable For example, a module named Verify Customer Number is highly cohesive. On the other hand Calculate and Print Statements is not as cohesive. Coupling: Describes the relationships and interdependence among modules. Modules that are independent are loosely coupled, which is desirable. Loosely coupled modules are easier to maintain and modify because changing the logic in one does not affect the other modules. Tightly coupled modules are not desired since one module might refer to internal logic contained in another. If program error  could cause processing sequence error Fig.9-13, pg. 423

Structured Application Development Structure Chart Examples

Testing the System After coding, a programmer must test each program to make sure that it functions correctly Syntax errors Desk checking Logic errors Structured walkthrough, or code review Design walkthrough After coding, a programmer must test each program to make sure that it functions correctly. Later programs are tested in groups, and finally the development team must test the entire system. First step is to compile program using a CASE tool or language compiler. This detects syntax errors which are programming language grammar errors. Next, the programmer desk checks the program by reviewing the code to spot logic errors  which are flaws in the design of the program. Many companies require a form type of desk checking called a structured walkthrough or code review. 3-5 peers participate. During the code review, the programmer explains the logic of the program code while other programmers step through the program logic. The project team also holds a session with users called a design walkthrough to review the interface with a cross-section of people who will work with the new system. They can make sure all necessary and agreed upon features have been included. Note the testing that is performed. Discuss Figure 9-23.

Testing the System Unit Testing Test data Stub Testing Test plan Test Data – should contain correct data and erroneous data and should test all possible situation that could occur. Ex. For a field that allows a range of numeric values, the test data should contain min values, max values, values outside acceptable range, and alphanumeric characters. Unit testing tests individual modules, or small groups of interrelated modules that always are executed as a group, before they are integrated with other modules. Unit testing attempts to locate and correct errors before modules are combined. Errors are much more difficult to find and fix after many modules are joined. Stub testing. A stub is a module, developed during testing, that simulates a module that has not yet been written. In stub testing, the programmer stimulates each program outcome or result and displays a message to indicate whether or not the program executed successfully. Test plan – Someone other than the programmer should write the test plan and create test data. A test plan consists of detailed procedures that specify how and when the testing will be performed, who will participate, and what test data will be used. It should include scenarios for every possible situation the program could encounter. Regardless of who creates the test plan, the project manager or a designated analyst also reviews the final test results.

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 Integration Testing – testing 2 or more programs that depend on each other Because few modules operate in isolation, integration testing is important Unit testing should be performed properly before a testing sequence moves to integration testing. Errors identified during integration testing can result from a number of problems, including: The wrong type of data (such as a word instead of a number) being passed from one module to another An unexpected value (such as a negative number for a price) being passed from one module to another A module generating an error (such as “file already in use”) due to conflicting resource needs Unexpected interactions (such as typical records, followed by a blank record) being passed from one module to another

Testing the System System Testing - 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

Testing the System System Testing - Major objectives: 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

Testing the System System Testing Called 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

Documentation Documentation Program Documentation System Documentation Operations Documentation User Documentation Online documentation Documentation – describes an information system and helps users, managers, and IT staff interact with it. Program Documentation – describes the inputs, outputs, and processing logic for all program modules. Includes process descriptions, report layouts. System Documentation – describes the system’s functions and how they are implemented. Includes data dictionary entries, DFD, object models, screen layouts, source documents, system request. Operations Documentation – If involves minicomputer, mainframe, or centralized servers, must prepare documentation for IT group that supports centralized operations. Contains information needed for processing and distributing online and printed output. User Documentation – consists of instructions and information to users who will interact with the system Includes user manuals, help screens, and tutorials.

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

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

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

Operational and Test Environments

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

Training 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

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 Center for the Application of Information Technologies (CAIT)

Training 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: 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

Training In-House Training 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

Data Conversion Data Conversion Strategies Data Export – ASCII or ODBC Program Some manual entry When a new system replaces an existing system, you should automate the data conversion process whenever possible. This cuts down on errors. 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 ODBC is a form of middleware that will allow the old system and new to interact and exchange data. 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

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

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 There are 4 system changeover methods: Direct cutover, parallel operation, pilot operation, and phased operation. When deciding which method to go with, you need to ask: How expensive is the changeover method? How much risk is involved in the changeover method? How difficult will it be to detect and correct errors? How much training will be needed for users? If companies have a choice, direct cutover typically is used when: They are implementing commercial software packages The new system is not replacing an older system Downtime of a few days or weeks can be tolerated Cyclical information systems are usually converted using the direct cutover method at the beginning of a quarter, calendar year, or fiscal year

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 Extra costs associated with parallel operation include: Hiring temporary (or temporarily reassigning existing) personnel Acquiring extra space and/or equipment Increasing managerial complexity Parallel operation generally is best used when the consequences of system failure are severe. This often is the case with mission critical applications such as transaction processing, production control, accounting functions, and customer service.

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 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

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 Is less expensive than full parallel operation Is not possible, however, if the system cannot be separated easily into logical modules or segments The primary disadvantage of phased operation is increased complexity — dividing the changeover process into phases creates more activities, thus making the process more complicated. Phased operation is best used when a system is large, complex, and composed of relatively independent subsystems.

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

Post-Implementation Tasks Post-Implementation Evaluation Includes feedback for the following areas: Effectiveness of database implementation Performance of the IT team Completeness and quality of documentation Quality and effectiveness of training Accuracy of cost-benefit estimates and development schedules

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 Use questionnaires to gather information and opinions form a large number of users Analyze maintenance and help desk logs

Post-Implementation Tasks 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

Post-Implementation Tasks 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 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

Chapter Summary Develop a training program 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 49

Chapter Summary Any questions? 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 Any questions? 49