The integrated use of conventional software engineering modeling (and possibly formal methods), program verification (correctness proofs), ...
The integrated use of conventional software engineering modeling (and possibly formal methods), program verification (correctness proofs), and statistical SQA have been combined into a technique that can lead to extremely high-quality software. Cleanroom software engineering is an approach that emphasizes the need to build correctness into software as it is being developed. Instead of the classic analysis, design, code, test, and debug cycle, the cleanroom approach suggests a different point of view:
The philosophy behind cleanroom software engineering is to avoid dependence on costly defect removal processes by writing code increments right the first time and verifying their correctness before testing. Its process model incorporates the statistical quality certification of code increments as they accumulate into a system.
In many ways, the cleanroom approach elevates software engineering to another level. Like the formal methods , the cleanroom process emphasizes rigor in specification and design, and formal verification of each design element using correctness proofs that are mathematically based. Extending the approach taken in formal methods, the cleanroom approach also emphasizes techniques for statistical quality control, including testing that is based on the anticipated use of the software by customers.
When software fails in the real world, immediate and long-term hazards abound. The hazards can be related to human safety, economic loss, or effective operation of business and societal infrastructure. Cleanroom software engineering is a process model that removes defects before they can precipitate serious hazards.
