Software process and characters
- 1. Characterizing the Software Process: A Maturity Framework β’ Watts S. Humphrey β’ March 1988, Software Engineering Institute Presented by: Maryam Ebrahimi Cs5391 Spring 2003
- 2. Overview β’ Introduction β’ Characteristic of Ideal Software Process Predictability statistical control Measurement β’ Development-process improvement 1- understanding the current status of development process 2- developing a vision of the desired process. 3- establishing a list of prioritized required actions. 4- producing a plan to accomplish these actions 5- commit the resources to execute the plan.
- 3. Overview β’ Five levels of Process Maturity Framework by SEI: 1- Initial Process 1-1 Project management 1-2 Management oversight 1-3 Quality assurance group 1-4 Change control 2- Repeatable Process 2-1 Establish a process group 2-2 Establish a software-development process architecture 2-3 introduce a family of software-engineering methods and technologies
- 4. Overview 3- Defined Process 3-1 Establish a minimum, basic set of process measurements 3-2 Establish a process database 3-3 provide sufficient process resources to gather and maintain this data 3-4 Assess the relative quality of each product 4- Managed Process 4-1 Support automatic gathering of process data 4-2 Analyze and modify the process 5- Optimizing Process β’ How to use this framework β’ Conclusion
- 5. Introduction This article presents a maturity framework that can be used by any software organization to: 1- Identify its highest priority problems 2- Assess its own capabilities 3- Start making improvements.
- 6. Characteristic of Ideal Software Process Predictable: Cost estimates and schedule commitments are met with reasonable consistency and the quality of the resulting products generally meet user needs. Statistical Control To achieve better result, the development process must be under statistical control.when a process is under statistical control, repeating the work in roughly the same way will produce roughly the same result. While there are some important differences, the concepts of statistical control applied to industry are applicable to software as well.
- 7. Characteristics of Ideal Software Process Measurement The basic principle behind statistical control is measurement. If our knowledge can not be expressed in numbers, it is of a meager and unsatisfactory kind. There are several factors to consider in measuring the programming process.Perhaps the most important is that the mere act of measuring human processes changes them. Since peopleβs fears and motivations are involved, the results must be viewed in a different light than data on natural phenomena.
- 8. Development-process improvement β’ First important step in addressing software problems is to treat the entire development task as a process that can be controlled, measured, and improved. β’ To improve their software capabilities, organizations must take five steps: β’ 1- understand the current status of their development process β’ 2- develop a vision of the desired process. β’ 3- establish a list of required process improvement actions in order of priority. β’ 4- produce a plan to accomplish these actions β’ 5- commit the resources to execute the plan.
- 9. A Maturity Framework β’ The maturity framework, developed at the SEI, addresses these five steps by characterizing a software process into one of the five maturity levels. β’ By establishing their organizationβs position in this maturity structure, software professionals and management can more readily identify those areas where improvement actions are most likely to produce results.
- 11. Process Maturity levels β’ 1- Initial Process: Is called ad hoc and often even chaotic. The organization operates without formalized procedures, cost estimates, and project plans. β’ If there is formal procedures for project control, there is no management mechanism to ensure they are used. The best test to observe how such an organization behaves in a crisis is: β’ Abandoning established procedures and reverting to merely coding and testing. β’ Organizations at this level can improve their performance by instituting basic project controls. The most important are:
- 12. Initial process(cont.) β’ 1-1 Project management. The fundamental role of a p.m. system is to ensure effective control of commitments which requires adequate preparation, clear responsibility, a public declaration, and a dedication to performance. β In any projects, a plan must be developed to determine the best schedule and the resources required. In the absence of such an orderly plan, no commitment can be better than an educated guess. β’ 1-2- Management oversight. A disciplined software development organization must have senior management oversight that review and approve all major plans before official commitment.
- 13. Initial process β’ 1-3- Quality assurance. A quality assurance group is charged with assuring management that the software development work is actually done the way it is supposed to be done. To be effective, the assurance organization must have an independent reporting line to senior management and sufficient resources to monitor performance of all key planning, implementation, and verification activities. β’ 1-4- Change control. To develop quality software on a predictable schedule, the requirements must be maintained with reasonable stability throughout the development cycle. Changes will have to be made, but must be managed and introduced in an orderly way.
- 14. Repeatable Process(cont.) β’ 2- Repeatable Process: β’ The organization has achieved a stable process with a repeatable level of statistical control by initiating rigorous project management of commitments, cost, schedule, and changes. β’ This process has one important strength over the initial process: it provides commitment control. β’ Organizations at this level face major risks when they are presented with new challenges. Examples of the changes that represent the highest risk are: β’ It is possible for a new technology to do more harm than good, if there is no defined process framework.
- 15. Repeatable Process(cont.) β’ When the organization must develop a new kind of product, it is entering new territory. For example, a software group that has experience developing compilers will likely have design, scheduling, and estimating problems if assigned to write a control program. Similarly, a group that has developed small, self-contained programs will not understand the interface and integration issues involved in large scale projects. These changes can be disruptive. β’ In this level, a new manager has no orderly basis for understanding what is going on and new team members must learn the ropes through word of mouth. β’ The key actions required to advance from the Repeatable Process to the Defined Process are:
- 16. Repeatable Process(cont.) β 2-1- Establish a process group which is a technical group that focuses exclusively on improving the software developing process. In most software organizations, people are entirely devoted to product work.. Until someone is given a full-time assignment to work on the process, little orderly progress can be made in improving it. β The responsibilities of process groups include: defining the development process, identifying technology needs and opportunities, conducting quarterly management that reviews process status and performance. β Typically, the process group should be about 1 to 3 percent the size of the organization, small organizations should address these issues through specially formed committees of experienced professionals or by retaining consultants.
- 17. Repeatable Process β’ 2-2- Establish a software-development process architecture that describes the technical and management activities required for proper execution of the development process. The architecture is a structural decomposition of the development cycle into tasks, each of which has entry criteria, fundamental descriptions, verification procedures, and exit criteria. The decomposition continues until each defined task is performed by an individual or single management unit. β’ 2-3- If they are not already in place, introduce a family of software- engineering methods and technologies. These include design and code inspections, formal design methods, library-control systems, and comprehensive testing methods, prototyping and adoption of modern implementation languages..
- 18. Defined Process(cont.) β’ 3- Defined process:To ensure consistent implementation and provide a basis for better understanding of the process, the organization has defined the process. At this point that the organization achieved the foundation for major and continuing progress, advanced technology can usefully be introduced. The development group, when faced with a crisis, will likely continue to use the Defined Process. β’ The foundation has now been established for examining the process and deciding how to improve it β’ As powerful as this step is, it is still only qualitative: There is little data to indicate what is going on or how effective the process really is. There is considerable debate about the value of software process measurements and the best ones to use.
- 19. Defined Process(cont.) β’ This uncertainty stems from a lack of process definition and the consequent confusion about the specific items to be measured.With a defined process, we can focus the measurements on specific tasks. β’ The key steps to advance to the Managed Process are: 3-1- Establish a minimum, basic set of process measurements to identify the quality and cost parameters of each process step. The objective is to quantify the relative costs and benefits of each major process activity, such as the cost and yield of error detection and correction methods. 3-2- Establish a process database with the resources to manage and maintain it.Cost and yield data should be maintained centrally to guard against loss, to make it available for all projects, and to facilitate process quality and productivity analysis.
- 20. Defined Process 3-3- provide sufficient process resources to gather and maintain this data and to advise project members on its use. Assign skilled professionals to monitor the quality of the data before entry in the database and to provide guidance on analysis methods and interpretation. 3-4- Assess the relative quality of each product and inform management where quality targets are not being met. An independent quality-assurance group should assess the quality actions of each project and track its progress against its quality plan.When this progress is compared with the historical experience on similar projects, an informed assessment generally can be made.
- 21. Managed Process(cont.) β’ 4- Managed Process: The organization has initiated comprehensive process measurements, beyond those of cost and schedule performance. This is when the most significant quality improvements begin. β’ The greatest potential problem with the Managed Process is the cost of gathering data. There are an enormous number of potentially valuable measures of software development and support, but such data is expensive to gather and maintain. β’ Process data must not be used to compare projects or individuals. Its purpose is to illuminate the product being developed and to provide an informed basis for improving the process.
- 22. Managed Process β’ The followings are two fundamental requirements to advance from the Managed Process to the Optimizing Process: β’ 4-1-Support automatic gathering of process data. Some data cannot be gathered by hand, and all manually gathered data is subject to error and omission. β’ 4-2- Analyzing and modifying the process by using this data to prevent problems and improve efficiency.
- 23. Optimizing Process(cont.) β’ 5- Optimizing Process: In varying degrees, Process Optimization goes on at all levels of process maturity. However, with the step from the Managed to the Optimizing Process there is a paradigm. Up to this point, software development managers have largely focused on their products and will typically only gather and analyze data that directly relates to product improvement. In the Optimizing Process, the data is available to actually tune the process itself. β’ With a little experience, management will see that process optimization can produce major quality and productivity improvements.
- 24. β’ For example, many errors can be identified and fixed far more economically by code inspections than through testing. It takes about one to four working hours to find and fix a bug through inspections and about 15 to 20 working hours to find and fix a bug in a function or system test. It is thus clear that testing is not a cost-effective way to find and fix most bugs. But it would be unwise to eliminate testing completely because it provides a useful check against human errors. β’ In the optimizing process, the organization has the means to identify the weakest elements of the process and fix them, the data is available to justify the application of technology to various critical tasks. Optimizing Process(cont.)
- 25. Optimizing Process β’ The Optimizing Process provides a disciplined environment for professional work. Discipline is required in large software projects to ensure, for example, that the people involved use the same conventions, donβt damage each otherβs products, and properly synchronize their work. β’ There is little data on how long it takes for software organizations to advance through these maturity levels toward the Optimizing Process. Based on authorβs experience, transition from level 1 to level 2 or from level 2 to level 3 takes from one to three years, even with a dedicated management commitment to process improvement. To date, no complete organizations have been observed at levels 4 or 5.
- 26. How to use this framework β’ This process-maturity structure is intended to be used with an assessment methodology and a management system. Using this framework, the SEI has developed an assessment questionnaire and methodology. β’ The questionnaire has been reviewed by more than 400 organizations. Also, it has been completed by more than 50 programming professionals from nearly as many software organizations.
- 27. Conclusion β This software-development process maturity model provides a framework for assessing software organizations and identifying the priority areas for immediate improvement. β It also helps identify those places where advanced technology can be most valuable in improving the software development process.