Rapid Application Development Edit
Rapid Application Development (RAD) is an iterative software methodology that uses prototypes, CASE tools, and flexible Management to develop application systems . RAD attempts to address both weaknesses of structured design methodologies by adjusting the SDLC phases to get some part of the system developed quickly and into the hands of the users. RAD Methodologies allows users to better understand the system and suggest revisions that bring the system closer to what is needed .
Analysts using RAD methodologies use computer tools like CASE tools. Computer-Aided Software Engineering (CASE), in the field of Software Engineering is the scientific application of a set of tools and methods to a software system, which is meant to result in high-quality, defect-free, and maintainable software products. It also refers to methods for the development of information systems together with automated tools that can be used in the software development process .
Management using RAD methodologies holds Joint Application Design (JAD) sessions in order to drive requirements from high level management and IT Specialists.
Phased Development Edit
A phased development based methodology breaks an overall system into a series of versions, which are developed sequentially. The most important and fundamental requirements are bundled into the first version of the system. The analysis phase then leads into design and implementation for those sets of requirements in version 1. Once version 1 is complete, version 2 undergoes analysis that builds on the previous analysis of version 1. Version 2 corrects issues that arose from the users’ experience with version 1. Version 2 is then implemented and then work begins on the next version. This process continues until the software is complete or the system is no longer being used .
A prototyping based Methodology performs analysis, design, and implementation phases concurrently, and all three phases are performed repeatedly in a cycle until the system is complete. Prototyping uses the basics of analysis and design to produce a “quick-n-dirty” system prototype. The prototype is then shown to end users and high-level management who provide suggestions on how to mold it to their needs. These suggestions are then used to reanalyze, redesign, and implement a second prototype, which provides the suggested features. This suggestion to tweak the prototype process continues in a cycle until analysts, sponsors, and end users agree that the prototype provides enough functionality to be used by the organization .
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