Cleanroom Software Engineering

Introduction to cleanroom software engineering

• It is an engineering approach which is used to build correctness in developed software.
• The main concept behind the cleanroom software engineering is to remove the dependency on the costly processes.
• The cleanroom software engineering includes the quality approach of writing the code from the beginning of the system and finally gathers into a complete a system.

• In this task, the incremental plan is developed.
• The functionality of each increment, projected size of the increment and the cleanroom development schedule is created.
• The care is to be taken that each increment is certified and integrated in proper time according to the plan.

• Requirement gathering is done using the traditional techniques like analysis, design, code, test and debug.
• A more detailed description of the customer level requirement is developed.

• The specification method uses box structure.
• Box structure is used to describe the functional specification.
• The box structure separate and isolate the behaviour, data and procedure in each increment.

• The cleanroom design is a natural specification by using the black box structure approach.
• The specification is called as state boxes and the component level diagram called as the clear boxes.

• The cleanroom conducts the exact correctness verification activities on the design and then the code.
• Verification starts with the highest level testing box structure and then moves toward the design detail and code.
• The first level of correctness takes place by applying a set of 'correcting questions'.
• More mathematical or formal methods are used for verification if correctness does not signify that the specification is correct.

• The box structure specification is represented in a specialized language and these are translated into the appropriate programming language.
• Use the technical reviews for the syntactic correctness of the code.

• Analyzed, planned and designed the projected usages of the software.
• The cleanroom activity is organized in parallel with specification, verification and code generation.

• The exhaustive testing of computer software is impossible. It is compulsory to design limited number of test cases.
• Statistical use technique execute a set of tests derived from a statistical sample in all possible program executions.
• These samples are collected from the users from a targeted population.

• After the verification, inspection and correctness of all errors, the increments are certified and ready for integration.

Cleanroom process model

• The modeling approach in cleanroom software engineering uses a method called box structure specification.
• A 'box' contains the system or the aspect of the system in detail.
• The information in each box specification is sufficient to define its refinement without depending on the implementation of other boxes.

• The black box identifies the behavior of a system.
• The system responds to specific events by applying the set of transition rules.

• The box consist of state data or operations that are similar to the objects.
• The state box represents the history of the black box i.e  the data contained in the state box must be maintained in all transitions.

• The transition function used by the state box is defined in the clear box.
• It simply states that a clear box includes the procedural design for the state box.