DFC3043 SYSTEM ANALYSIS & DESIGN
CHAPTER 5
SYSTEM IMPLEMENTATION AND SUPPORT
LEARNING OUTCOMES
5.1
Understand system development
5.2
Understand testing in a project
5.3
Explain system implementation
5.4 Understand systems support and security
LEARNING OUTCOMES
5.1
Understand system development
5.2
Understand testing in a project
5.3
Explain system implementation
5.4 Understand systems support and security
5.1 Understand System Development 5.1.1 Differentiate system development tools: a. Modeling b. Prototyping c. CASE Tools 5.1.2 Explain the coding process
5.1.1 Differentiate system development tools
Systems analyst must know how to use a variety of techniques, such as Mo Mode dell llin ing, g, Pr Prot otot otyp ypin ing, g, an and d Co Comp mput uter er-A -Aid ided ed Sy Syst stem emss Engin En ginee eeri ring ng (C (CASE ASE)) tools.
Why:
To und unders erstand tanding ing busi business ness oper operatio ations ns
To plan in a team environment, where input from users, mana ma nage gerrs, an and d IT st staf afff co con ntr trib ibut utes es to th the e sys yste tem m de desi sign gn
Modelling
Prototyping
CASE Tools
5.1.1 Differentiate system development tools
MODELING Modeling produces produces a • Modeling graphical representation of a concept or process that systems developers can analyze, test, and modify. • A systems analyst can describe and simplify an information system by using a set of business, data, object, network, and process models.
PROTOTYPING • Prototyping tests system concepts and provides an opportunity to examine input, output, and user interfaces before final decisions are made. • A prototype is an early working version of an Information system.
CASE TOOLS • Computer-aided systems engineering (CASE), also called computer-aided software engineering, is a technique that uses powerful software, called CASE tools, to help systems analysts develop and maintain information systems. • • CASE tools provide an overall framework for systems development development and support a wide variety of design methodologies, including structured analysis and object-oriented analysis.
5.1.1 Differentiate system development tools
MODELING
PROTOTYPING
CASE TOOLS
5.1.1 Differentiate system development tools
Modeling produces a graphical representation of a concept or process that systems developers can analyze, test, and modify. A system analyst can describe and simplify an information system by using a set of business, data, object, network, and process models. Eg: A business model/ requirements model, describes the information that a system must provide. A data model describes data structure and design. An object model describes objects, which combine data and processes. A network model describes the design and protocols of telecommunications links. A process model describes the logic that programmers use to write code modules. Although the models might appear to overlap, they actually work together to describe the same environment from different points of view.
Modelling
5.1.1 Differentiate system development tools
Reasons for Modeling Learning from the modeling process Reducing complexity by abstraction Remembering all of the details Communicating with other development teams members Communicating with a variety of stakeholders Documenting what was done for future maintenance/enhancement Examples of Models Used in Analysis Phase Data flow diagram (DFD) Entity-relationship diagram (ERD) Decision Table
Examples of Model Used in Design Screen layout Report layout System flowchart Database schema / Data Dictionary Network diagram
Modelling
5.1.1 Differentiate system development tools
Prototyping Purpose: To tests system concepts and provides an opportunity to examine input, output, and user interfaces before final decisions are made. A prototype is an early working version of an information system. Just as an aircraft manufacturer test a new design in a wind tunnel, systems analysts construct and study information systems prototypes. Advantage: A prototype can serve as an initial model that is used as benchmark to evaluate the finished system, or the prototype itself can develop into the final version of the system. Either way, prototyping speeds up the development process significantly. Possible Disadvantage: Important decisions might be made too early, before business or IT issues are understood thoroughly. A prototype based on careful fact finding and modelling techniques, however can be an extremely valuable tool.
Prototyping
5.1.1 Differentiate system development tools
CASE Tools
5.1.1 Differentiate system development tools
Computer-aided systems engineering (CASE), also called computer-aided software engineering What: A technique that uses powerful software, called CASE Tools CASE tools provide an over all framework for systems development and support a wide variety of design methodologies, including structured analysis and object-oriented analysis. Reason: to help system analyst’s develop and maintain information systems. How: Because CASE tools make it easier to build an information system, they boost it productivity and improved the quality of the finished product. Traditional CASE tools system developers often use project management tools, such as Microsoft Project, and special –purpose charting tools, such as Microsoft Visio. a system analyst’s can use Visio to create many different types of diagrams, including block diagrams. Building plans, forms and charts, maps, network diagrams, and organization charts. Example of CASE software are: Microsoft Visio Rational Rose Three leading CASE tool suppliers: Visible Systems Corporation, Telelogic Software, and
CASE Tools
5.1.1 Differentiate system development tools
CASE Tool Examples: Visible Analyst
Visible Systems Corporation is an important player in the software development market
Also provides a full range of Help features, including the error message analysis screen
CASE Tools
5.1.1 Differentiate system development tools
CASE Tool Examples: Rational Software
IBM offers many systems development and modelling products, including a powerful tool called Rational System Architect
Stresses modelling and collaboration, and is a suite of tools that can align processes, information, and technologies
CASE Tools
SYSTEM DEVELOPMENT – 5.1 2 CODING PROCESS
Coding is the process of turning program logic into specific instructions that the computer system can execute.
Working from a specific design, a programmer uses a programming language to transform program logic into code statements.
5.2 Understand testing in a project 5.2.1 Explain the importance of software quality assurance 5.2.2 Differentiate the types of software testing: - Unit testing - Integration testing - System testing 5.2.3 Differentiate between program, system, operations and user documentation
5.2.1 Explain the importance of software quality assurance.
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
5.2.1 Explain the importance of software quality assurance.
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Software Engineering 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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•
•
5.2.1 Explain the importance of software quality assurance. •
International Organization for Standardization (ISO) –
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Many firms seek assurance that software systems will meet rigid quality standards ISO 90003:2004 ISO requires a specific development plan
5.2.2 Differentiate the types of software testing
Three types of software testing
Unit Testing
Integration Testing
System Testing
You should regard thorough testing as a cost-effective means of providing a quality product
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5.2.2 Differentiate the types of software testing Unit Testing: Unit testing involves individually testing unit of code separately to make sure that it works on its own, independent of the other units. Eg: Testing a function; whether loop or statement in a program is working properly or not than this is called as unit testing Integration Testing: Test the modules to ensure whether they are integrating properly or not by combining the modules and tested as a group. Eg: Tester have to test the keyboard of a computer than it is a unit testing but when tester have to combine the keyboard and mouse of a computer together to see its working or not than it is the integration testing. It is prerequisite that for performing integration testing a system must be unit tested before.
5.2.2 Differentiate the types of software testing
System Testing: Tester test the complete system as a whole to check whether the system is properly working or vice versa as per the requirements or not. Testers always have to concentrate on both functional and non-functional testing like performance, load, stress, security and recovery testing In summary: in system testing the testers test the complete system as a whole. Eg: Test the whole functionality and non functionality of the system interactions between all module in Laundry Management System as one single system. It is prerequisite that for performing system testing a system must be unit tested and integration tested before.
5.2.3 Differentiate between program, system, operations, and user documentation.
Program Documentation
System Documentation
Operations Documentation
User Documentation
Systems analysts usually are responsible for preparing documentation to help users learn the system
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5.2.3 Differentiate between program, system, operations, and user documentation. Program documentation describes the inputs, outputs, and processing logic for all program modules.
System documentation describes the system’s functions and how they are implemented. System documentation includes data dictionary entries, data flow diagrams, object models, screen layouts, source documents, and the systems request that initiated the project.
5.2.3 Differentiate between program, system, operations, and user documentation. Operations documentation contains all the information needed for processing and distributing online and printed output. Typical examples of operations documentation includes the following information:
Program, systems analyst, programmer, and system identification Scheduling information for printed output, such as report run frequency and deadlines Input files and where they originate; and output files and destinations E-mail and report distribution lists Special forms required, including online forms 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.
5.2.3 Differentiate between program, system, operations, and user documentation.
What is User Documentation?
User documentation consists of instructions and information to users who will interact with the system and includes user manuals, Help screens, and tutorials. Programmers or systems analysts usually create program documentation and system documentation.
5.2.3 Differentiate between program, system, operations, and user documentation.
User Documentation
Effective online documentation is an important productivity tool
Written documentation material also is valuable
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5.3 Explain System Implementation 5.3.1 List the main steps in system implementation 5.3.2 Explain system installation and evaluation 5.3.3 Outline system installation and evaluation checklist
5.3 Explain system implementation. Management Approval
After system testing is complete, developer team need to 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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5.3.1 List the main steps in system implementation.
The new system now is ready to go to work. Now, you will carry out the remaining steps in systems implementation: 1.
Prepare a separate operational and test environment
2.
Provide training for users, managers, and IT staff
3.
Perform data conversion and system changeover
4.
Carry out a post-implementation evaluation of the system
5.
Present a final report to management
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5.3.2 System Installation And Evaluation
1. Operational and test environment
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.
5.3.2 System Installation And Evaluation 2. Provide training for users, managers, and IT staff Training Plan - it is essential to provide the right training for the right people at the right time, specific training topics, identify the objectives, and determine how the company will provide training. The main choices are to obtain training from vendors, outside training firms, or use IT staff and other in-house resources. Vendor Training - Many hardware and software vendors offer training programs free or at a nominal cost for the products they sell. The training usually is conducted at the vendor’s site by experienced trainers who provide valuable hands-on experience. Vendor training often gives the best return on your training dollars because it is focused on products that the vendor developed. Many vendors offer Web-based training options, including Webinars, podcasts, and tutorials. In-house Training - The IT staff and user departments often share responsibility for developing and conducting training programs for internally developed software. If your organization has a help desk, the staff might be able to handle internally user training.
5.3.2 System Installation And Evaluation 3. Data Conversion
Data conversion is an important part of the system installation process. During data conversion, existing data is loaded into the new system.
Data Conversion Strategy - When a new system replaces an existing system, you should automate the data conversion process, if possible.
The old system might be capable of exporting data in an acceptable format for the new system or in a standard format. If a standard format is not available, you must develop a program to extract the data and convert it to an acceptable format.
5.3.2 System Installation And Evaluation 3. System Changeover
System changeover is the process of putting the new information system online and retiring the old system.
Changeover can be rapid or slow, depending on the method. The four changeover methods are : 1.
direct cutover
2.
parallel operation
3.
pilot operation
4.
phased operation
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 35
System Changeover
Parallel Operation –
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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 36
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 37
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
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System Changeover summary risk vs cost
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5.3.2 System Installation And Evaluation 4. Post-implementation Evaluation
A post-implementation evaluation assesses the overall quality of the information system.
The evaluation verifies that the new system meets specified requirements, complies with user objectives, and produces the anticipated benefits.
5. Final Report to Management The final report to management marks the end of systems development work. 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 • Comparison of actual costs and schedules to the original estimates • Post-implementation evaluation, if it has been performed
Data Conversion
Data Conversion Security and Controls
The developer team 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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5.4 Understand Systems Support and Security 5.4.1 Explain the system support and security phase 5.4.2 Identify user support: User training Help desk 5.4.3 Explain various types of maintenance: Corrective maintenance Adaptive maintenance Perfective maintenance Preventive maintenance 5.4.4 Identify tools for system maintenance 5.4.5 Explain the system security and backup 5.4.6 Identify three elements of system security
5.4.1 Explain the system support and security phase
Systems support and security is the final phase in the systems development life cycle.
Managing systems support and security involves three main concerns: 1.user
expectations
2.system
performance
3.security
requirements
5.4.2 Identify user support: User Training
New employees must be trained on the company’s information systems. The main objective is to show users how the system can help them perform their jobs. The training could include online support via e-mail, a special Web site, a revision to the user guide, a training manual supplement, or formal training sessions.
Help Desks To make data more accessible and to empower users, many IT departments create help desks. A help desk is a centralized resource staffed by IT professionals who provide users with the support they need to do their jobs. A help desk has three main objectives: 1.Show people how to use system resources more effectively 2.Provide answers to technical or operational questions 3.Make users more productive by teaching them how to meet their own information needs A help desk often is called an information center (IC) because it is the first place users turn when they need information or assistance.
5.4.3 Explain various types of maintenance: What is system maintenance? System maintenance is the process of refining the system to make sure it continues to meet business needs.
Corrective Maintenance Corrective maintenance diagnoses and corrects errors in an operational system. To avoid introducing new problems, all maintenance work requires careful analysis before making changes. Adaptive Maintenance Adaptive maintenance adds enhancements to an operational system and makes the system easier to use. Perfective Maintenance Perfective maintenance involves changing an operational system to make it more efficient, reliable, or maintainable. Requests for corrective and adaptive
maintenance normally come from users, while the IT department usually initiates perfective maintenance. Preventive Maintenance To avoid problems, preventive maintenance requires analysis of areas where trouble is likely to occur. Like perfective maintenance, the IT department normally initiates preventive maintenance. Preventive maintenance often results in increased user satisfaction, and decreased downtime.
5.4.4 Identify tools for system maintenance Many CASE tools include system evaluation and maintenance features, including the following examples:
Performance monitor that provides data on program execution times
Program analyzer that scans source code, provides data element cross-reference information, and helps evaluate the impact of a program change
Interactive debugging analyzer that locates the source of a programming error
Reengineering tools
Automated documentation
Network activity monitor
Workload forecasting tool
5.4.5 Explain the system security and backup BACKUP AND RECOVERY
Every system must provide for data backup and recovery.
Backup refers to copying data at prescribed intervals, or continuously.
Recovery involves restoring the data and restarting the system after an interruption.
An overall backup and recovery plan that prepares for a potential disaster is called a disaster recovery plan .
BACKUP TYPES
Backups can be full, differential, incremental, or continuous.
Backup Policies
The cornerstone of business data protection is a backup policy, which contains detailed
5.4.5 Explain the system security and backup BACKUP TYPES
Backups can be full, differential, incremental, or continuous.
Backup Policies
The cornerstone of business data protection is a backup policy, which contains detailed instructions and procedures.
An effective backup policy can help a firm continue business operations and survive a catastrophe.
The backup policy should specify backup media, backup types, and retention periods.
5.4.5 Explain the system security and backup
Backup Types Very Famous!
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5.4.5 Explain the system security and backup To provide system security, you must consider six separate but interrelated levels:
physical security,
network security,
application security,
file security,
user security, and
procedural security.
Like the chain shown in Figure 12-26, system security is only as strong as the weakest link.
5.4.6 Identify three elements of system security
Security is a vital part of every computer system
System Security Concepts, CIA triangle:
Integrity
Availability
Security policy / Confidentiality
Very Famous!
Also known as:
3 Elements of System Security
3 Elements of System Security 51
5.4.6 Identify three elements of system security System Security Elements The CIA triangle in Figure 12-20 shows the three main elements of system security: confidentiality, integrity, and availability.
Confidentiality protects information from unauthorized disclosure and safeguards privacy.
Integrity prevents unauthorized users from creating, modifying, or deleting information.
Availability ensures that authorized users have timely and reliable access to necessary information.
