Cleanroom Software Engineering
Encyclopedia
The Cleanroom software engineering process is a software development process
intended to produce software with a certifiable level of reliability
. The Cleanroom process was originally developed by Harlan Mills
and several of his colleagues including Alan Hevner at IBM
. The focus of the Cleanroom process is on defect prevention, rather than defect removal. The name Cleanroom was chosen to evoke the cleanroom
s used in the electronics industry to prevent the introduction of defects during the fabrication of semiconductor
s. The Cleanroom process first saw use in the mid to late 80s. Demonstration projects within the military began in the early 1990s. Recent work on the Cleanroom process has examined fusing Cleanroom with the automated verification capabilities provided by specifications expressed in CSP
.
Software development based on formal methods
: Cleanroom development makes use of the Box Structure Method to specify and design a software product. Verification that the design correctly implements the specification is performed through team review.
Incremental implementation under statistical quality control: Cleanroom development uses an iterative approach, in which the product is developed in increments that gradually increase the implemented functionality. The quality of each increment is measured against pre-established standards to verify that the development process is proceeding acceptably. A failure to meet quality standards results in the cessation of testing for the current increment, and a return to the design phase.
Statistically sound testing
: Software testing in the Cleanroom process is carried out as a statistical experiment. Based on the formal specification, a representative subset of software input/output trajectories is selected and tested. This sample is then statistically analyzed to produce an estimate of the reliability of the software, and a level of confidence in that estimate.
Software development process
A software development process, also known as a software development life cycle , is a structure imposed on the development of a software product. Similar terms include software life cycle and software process. It is often considered a subset of systems development life cycle...
intended to produce software with a certifiable level of reliability
Reliability engineering
Reliability engineering is an engineering field, that deals with the study, evaluation, and life-cycle management of reliability: the ability of a system or component to perform its required functions under stated conditions for a specified period of time. It is often measured as a probability of...
. The Cleanroom process was originally developed by Harlan Mills
Harlan Mills
Harlan D. Mills was Professor of Computer Science at the Florida Institute of Technology and founder of Software Engineering Technology, Inc. of Vero Beach, Florida . Mills' contributions to software engineering have had a profound and enduring effect on education and industrial practice. Since...
and several of his colleagues including Alan Hevner at IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
. The focus of the Cleanroom process is on defect prevention, rather than defect removal. The name Cleanroom was chosen to evoke the cleanroom
Cleanroom
A cleanroom is an environment, typically used in manufacturing or scientific research, that has a low level of environmental pollutants such as dust, airborne microbes, aerosol particles and chemical vapors. More accurately, a cleanroom has a controlled level of contamination that is specified by...
s used in the electronics industry to prevent the introduction of defects during the fabrication of semiconductor
Semiconductor
A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
s. The Cleanroom process first saw use in the mid to late 80s. Demonstration projects within the military began in the early 1990s. Recent work on the Cleanroom process has examined fusing Cleanroom with the automated verification capabilities provided by specifications expressed in CSP
Communicating sequential processes
In computer science, Communicating Sequential Processes is a formal language for describing patterns of interaction in concurrent systems. It is a member of the family of mathematical theories of concurrency known as process algebras, or process calculi...
.
Central principles
The basic principles of the Cleanroom process areSoftware development based on formal methods
Formal methods
In computer science and software engineering, formal methods are a particular kind of mathematically-based techniques for the specification, development and verification of software and hardware systems...
: Cleanroom development makes use of the Box Structure Method to specify and design a software product. Verification that the design correctly implements the specification is performed through team review.
Incremental implementation under statistical quality control: Cleanroom development uses an iterative approach, in which the product is developed in increments that gradually increase the implemented functionality. The quality of each increment is measured against pre-established standards to verify that the development process is proceeding acceptably. A failure to meet quality standards results in the cessation of testing for the current increment, and a return to the design phase.
Statistically sound testing
Software testing
Software testing is an investigation conducted to provide stakeholders with information about the quality of the product or service under test. Software testing can also provide an objective, independent view of the software to allow the business to appreciate and understand the risks of software...
: Software testing in the Cleanroom process is carried out as a statistical experiment. Based on the formal specification, a representative subset of software input/output trajectories is selected and tested. This sample is then statistically analyzed to produce an estimate of the reliability of the software, and a level of confidence in that estimate.