Rapid application development

"RAD tool" and "Rapid Application Development Tool" redirect here. For development tools focused on making graphical user interfaces, see graphical user interface builder.
Software development process
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Rapid application development (RAD) is both a general term used to refer to alternatives to the conventional waterfall model of software development as well as the name for James Martin's approach to rapid development. In general, RAD approaches to software development put less emphasis on planning and more emphasis on process. In contrast to the waterfall model, which calls for rigorously defined specification to be established prior to entering the development phase, RAD approaches emphasize adaptability and the necessity of adjusting requirements in response to knowledge gained as the project progresses. Prototypes are often used in addition to or sometimes even in place of design specifications.

RAD is especially well suited (although not limited to) developing software that is driven by user interface requirements. Graphical user interface builders are often called rapid application development tools. Other approaches to rapid development include Agile methods and the spiral model.

History

Rapid application development is a response to processes developed in the 1970s and 1980s, such as the Structured Systems Analysis and Design Method and other Waterfall models. One of the problems with these methods is that they were based on a traditional engineering model used to design and build things like bridges and buildings. Software is an inherently different kind of artifact. Software can radically change the entire process used to solve a problem. As a result, knowledge gained from the development process itself can feed back to the requirements and design of the solution.[1] The waterfall solution to this was to try and rigidly define the requirements and the plan to implement them and have a process that discouraged changes to either. The new RAD approaches on the other hand recognized that software development was a knowledge intensive process and sought to develop flexible processes that could take advantage of knowledge gained over the life of the project and use that knowledge to reinvent the solution.

The first such RAD alternative was developed by Barry Boehm and was known as the spiral model. Boehm and other subsequent RAD approaches emphasized developing prototypes as well as or instead of rigorous design specifications. Prototypes had several advantages over traditional specifications:

Starting with the ideas of Barry Boehm and others, James Martin developed the rapid application development approach during the 1980s at IBM and finally formalized it by publishing a book in 1991, Rapid Application Development. This has resulted in some confusion over the term RAD even among IT professionals. It is important to distinguish between RAD as a general alternative to the waterfall model and RAD as the specific method created by Martin. The Martin method was tailored toward knowledge intensive and UI intensive business systems.

These ideas were further developed and improved upon by RAD pioneers like James Kerr and Richard Hunter, who together wrote the seminal book on the subject, Inside RAD,[3] which followed the journey of a RAD project manager as he drove and refined the RAD Methodology in real-time on an actual RAD project. These practitioners, and those like them, helped RAD gain popularity as an alternative to traditional systems project life cycle approaches.

The RAD approach also matured during the period of peak interest in business re engineering. The idea of business process re-engineering was to radically rethink core business processes such as sales and customer support with the new capabilities of Information Technology in mind. RAD was often an essential part of larger business re engineering programs. The rapid prototyping approach of RAD was a key tool to help users and analysts "think out of the box" about innovative ways that technology might radically reinvent a core business process.[4][5]

The James Martin RAD method

Phases in the James Martin approach to RAD

The James Martin approach to RAD divides the process into four distinct phases:

  1. Requirements planning phase – combines elements of the system planning and systems analysis phases of the Systems Development Life Cycle (SDLC). Users, managers, and IT staff members discuss and agree on business needs, project scope, constraints, and system requirements. It ends when the team agrees on the key issues and obtains management authorization to continue.
  2. User design phase – during this phase, users interact with systems analysts and develop models and prototypes that represent all system processes, inputs, and outputs. The RAD groups or subgroups typically use a combination of Joint Application Development (JAD) techniques and CASE tools to translate user needs into working models. User Design is a continuous interactive process that allows users to understand, modify, and eventually approve a working model of the system that meets their needs.
  3. Construction phase – focuses on program and application development task similar to the SDLC. In RAD, however, users continue to participate and can still suggest changes or improvements as actual screens or reports are developed. Its tasks are programming and application development, coding, unit-integration and system testing.
  4. Cutover phase – resembles the final tasks in the SDLC implementation phase, including data conversion, testing, changeover to the new system, and user training. Compared with traditional methods, the entire process is compressed. As a result, the new system is built, delivered, and placed in operation much sooner.[6]

Pros and cons of rapid application development

In modern Information Technology environments, many systems are now built using some degree of Rapid Application Development[7] (not necessarily the James Martin approach). In addition to Martin's method, Agile methods and the Rational Unified Process are often used for RAD development.

The advantages of RAD include:

The disadvantages of RAD include:

See also

References

  1. Brooks, Fred (1986). Kugler, H.J., ed. No Silver Bullet Essence and Accidents of Software Engineering (PDF). Information Processing '86. Elsevier Science Publishers B.V (North-Holland). ISBN 0-444-70077-3. Retrieved 2 July 2014.
  2. 1 2 Boehm, Barry (May 1988). "A Spiral Model of Software Development" (PDF). IEEE Computer. Retrieved 1 July 2014.
  3. Kerr, James M.; Hunter, Richard (1993). Inside RAD: How to Build a Fully Functional System in 90 Days or Less. McGraw-Hill. ISBN 0-07-034223-7.
  4. Drucker, Peter (November 3, 2009). Post-Capitalist Society. Harper Collins e-books. ISBN 0887306209.
  5. Martin, James (1991). Rapid Application Development. Macmillan. ISBN 0-02-376775-8.
  6. Martin, James (1991). Rapid Application Development. Macmillan. pp. 81–90. ISBN 0-02-376775-8.
  7. Hotle, Matt (April 13–14, 2010). "The Disintegration of AD: Putting it Back Together Again" (PDF). http://www.gartner.com.br. Enterprise Integration Summit, Sao Palo, Brazil: Gartner Group. Retrieved 1 July 2014. External link in |website= (help)
  8. Beck, Kent (2000). Extreme Programming Explained. Addison Wesley. pp. 3–7. ISBN 0201616416.
  9. Gerber, Aurona; Van Der Merwe, Alta; Alberts, Ronell (16–18 November 2007). "Practical Implications of Rapid Development Methodologies". Proceedings of the Computer Science and Information technology Education Conference, CSITEd-2007. Computer Science and IT Education Conference. Mauritius. pp. 233–245. ISBN 978-99903-87-47-6. Retrieved 9 October 2016.
  10. Andrew Begel, Nachiappan Nagappan. "Usage and Perceptions of Agile Software Development in an Industrial Context: An Exploratory Study, Microsoft Research" (PDF). Retrieved 2008-11-15.
  11. E. M. Maximilian and L. Williams. (2003). "Assessing Test-driven Development at IBM". Proceedings of International Conference of Software Engineering, Portland, OR, pp. 564-569, 2003.
  12. M. Stephens, Rosenberg, D. (2003). "Extreme Programming Re factored: The Case Against XP". Apress, 2003.

Further reading

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