Systems Analysis & Design 5 Edition th Chapter

Systems Analysis & Design 5 Edition th 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, installation, and evaluation Users will be working with the system on a day-to-day basis, and you will focus on system operation and support, which is the final phase in the SDLC 2

Chapter Objectives Explain the importance of software quality assurance and software engineering Describe the application development process Draw a structure chart showing topdown 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 4

Chapter Objectives Describe the data conversion process Identify and describe changeover methods Explain post-implementation evaluation Describe the final report to management 5

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 6

Software Quality Assurance In today’s competitive business environment, companies are intensely concerned with the quality of their products and services Rigorous testing catches errors in the implementation stage, but it is much less expensive to correct mistakes earlier in the development process The main objective of quality assurance is to avoid problems or to detect them as soon as possible 7

Software Quality Assurance Software Engineering – The Software Engineering Institute (SEI) at Carnegie Mellon University is a leader in software engineering – SEI designed a Capability Maturity Model (CMM) International Organization for Standardization (ISO) – In 1991, ISO established a set of guidelines called ISO 9000-3 – ISO requires a specific development plan, which outlines a step-by-step process for transforming user requirements into a finished product 8

Application Development Application development is the process of constructing the programs and code modules that are the building blocks of the information system Your first step in application development is to review carefully all existing documentation 9

Application Development Documentation Review – You will need solid documentation from prior SDLC phases to design programs and code modules – Using the system documentation as a blueprint, you will develop structure charts that break the system into smaller pieces that programmers can translate into programs and modules 10

Application Development Program Design – Must view the system as a series of interactive modules – Top-down design – partitioning – modular design – Use project management software Structure Charts – Structure charts show the program modules and the relationships among them – Control module – Subordinate modules 11

Application Development Structure Charts –Module Library module –Data Couple –Control Couple Flag A module uses a flag to signal a specific condition or action to another module 12

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 13

Application Development 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 – Passing status flags down from a control module generally is regarded as poor design 14

Application Development Structure Chart Examples 15

Application Development Steps in Drawing a Structure Chart – Step 1: Review the DFDs and Object Models Check for accuracy and completeness – Step 2: Identify Modules and Relationships You work your way down from the context diagram to the lower-level diagrams, identifying control modules and subordinate modules, until you reach functional primitives – Step 3: Add Couples, Loops, and Conditions Identify the data elements that pass from one module to another – Step 4: Analyze the Structure Chart, the DFDs, and the Data Dictionary Ensure that the chart reflects all previous documentation and that the logic is correct 16

Application Development Other Application Development Tools – Program Flowcharts Program flowcharts graphically represent the logic and interaction between program modules – Pseudocode Is not language-specific, so you can use it to describe a software module in plain English without requiring strict syntax rules 17

Coding Programming Environments – Each IT departments has its own programming environment and standards Generating Code – Use application generators, report writers, screen generators, fourth-generation languages, and other CASE tools – Can generate editable program code directly from macros, keystrokes, or mouse actions 18

Testing the System After coding, a programmer must test each program to make sure that it functions correctly Syntax errors Desk checking Structured walkthrough, or code review Design walkthrough 19

Testing the System Unit Testing – Test data should contain both correct data and erroneous data and should test all possible situations that could occur – 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 20

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 – Integration test data must consider both normal and unusual situations – A testing sequence should not move to the integration stage unless it has performed properly in all unit tests 21

Testing the System System Testing – Major objectives: Perform a final test of all programs 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 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 22

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 23

Documentation Program Documentation – This documentation guides programmers, who construct modules that are well supported by internal and external comments and descriptions that can be understood and maintained easily 24

Documentation System Documentation – Includes data dictionary entries, data flow diagrams, object models, screen layouts, source documents, and the systems request that initiated the project – During systems implementation, an analyst must review system documentation to verify that it is complete, accurate, and up-to-date, including any changes made during the implementation process 25

Documentation Operations Documentation – Includes the following information: Program, systems analyst, programmer, and system identification Scheduling information, such as report run frequency and deadlines Input files and where they originate; and output files and destinations Report distribution 26

Documentation Operations Documentation – Includes the following information: Special forms required Error and informational messages to operators and restart procedures Special instructions, such as security requirements – Operations documentation should be clear, concise, and available online if possible 27

Documentation User Documentation – Programmers or systems analysts usually create program and system documentation – You need someone with expert skills in this area doing the development, just as you need someone with expert skills developing the software – User documentation must be clear, understandable, and readily accessible to users at all levels 28

Documentation User Documentation – Includes the following: A system overview that clearly describes all major system features, capabilities, and limitations Description of source document content, preparation, processing, and samples Overview of menu and data entry screen options, contents, and processing instructions Examples of reports that are produced regularly or available at the user’s request, including samples 29

Documentation User Documentation – Includes the following: Security and audit trail information Explanation of responsibility for specific input, output, or processing requirements Procedures for requesting changes and reporting problems Examples of exceptions and error situations Frequently asked questions (FAQs) Explanation of how to get help and procedures for updating the user manual 30

Documentation User Documentation – Online documentation – Must determine whether the documentation will be available from within the program, or as a separate entity in the form of a tutorial, slide presentation, reference manual, or Web site – Effective online documentation is an important productivity tool 31

Documentation User Documentation – Written documentation material also is valuable – The time between finishing software coding and the time when a complete package can be released to users is entirely dependent on how well the documentation is thought out in advance 32

Documentation User Documentation – Neglecting user documentation issues until after all the program is complete often leads to one of two things: 1) the documentation will be thrown together as quickly as possible just to get it out the door on time, and it more than likely will be inadequate; or 2) it will be done correctly, and the product release will be delayed considerably 33

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 34

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 35

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 area is necessary to maintain system security and integrity and protect the operational environment 36

Operational and Test Environments Access to the operational environment is limited to users and must be strictly controlled The test environment for an information system contains copies of all programs, procedures, and test data files After any modification, you should repeat the same acceptance tests you ran when the system was developed 37

Operational and Test Environments The operational environment includes hardware and software configurations and settings, system utilities, telecommunications resources, and any other components that might affect system performance If you have to build or upgrade network resources to support the new system, you must test the platform rigorously before system installation begins 38

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 39

Training Vendor Training – If the system includes the purchase of software or hardware, then vendorsupplied 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 – Vendor training often gives the best return on your training dollars 40

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) 41

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 42

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 43

Data Conversion Data Conversion During data conversion, existing data is loaded into the new system You should develop a data conversion plan as early as possible, and the conversion process should be tested when the test environment is developed 44

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 45

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 46

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 47

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 48

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 49

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 50

System Changeover 51

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 52

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 53

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 54

Post-Implementation Tasks Post-Implementation Evaluation – When evaluating a system, you should: 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 55

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 56

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 A recap of all systems development costs and schedules 57

Post-Implementation Tasks Final Report to Management – Your report should include the following: A comparison of actual costs and schedules to the original estimates The post-implementation evaluation, if it has been performed. – Marks the end of systems development work 58

Chapter Summary The systems implementation phase consists of application development, testing, installation, and evaluation of the new system Analysts also prepare operations documentation and user documentation During the installation process, you establish an operational, or production, environment for the new information system that is completely separate from the test environment 59

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 60

Systems Analysis & Design 5 Edition th Chapter 9 Complete