Cambridge first started developing its RAD methodology for developing client-server solutions in 1991. Over the years , as client-server technologies matured, Cambridge continued to evolve its RAD model. Internet applications, however, including electronic commerce, extranets, on-line communities, interactive marketing, and interactive web services place new demands on software over and above traditional client-server development. The CoRAD methodology brings together four key disciplines for the rapid development of an Internet application:
Internet applications and online business have placed new technical demands on software architecture. Often, it is impossible to accurately predict how many people will use an Internet site. For example, when Netscape sized its first web site, it considered the NCSA site from which the original Mosaic web browser was distributed. At the time, NCSA was receiving 1.5 million "hits" per day. Netscape wanted to be able to handle at least three times that load and designed its site for 5 million hits a day. That number was surpassed in Netscape's first week of operation and the site routinely handles 150 million or more hits per day, or 100 times the original NCSA reference. While your site may not see this amount of growth, experts say an Internet architecture should be capable of scaling to handle ten times the expected load without reaching an architectural bottleneck. On an Internet site, you will have to consider the scalability of your application software; networking and security software must also scale commensurately with application usage.
Electronic commerce applications also have a major business impact. They affect how you market your products, how you sell, and how you service your customers. How will you transition your people to work in this new environment, or will you need new people? What new business processes will be needed? Will you need new channels or partners ?
Finally, the creative and cognitive skills needed for successful Internet applications are substantially different than traditional internal client-server applications. No matter how good the technology employed, the business goals of your electronic commerce application cannot be successfully achieved unless the targeted customers use the solution you provide. Experience on the Internet has proven this is not always the case. Today's electronic commerce customers typically have a choice. They may choose to use your interactive solution or choose not to. They may choose a competitor's web site or they may use another traditional channel offered by your own company. Traditional client-server application users have used the application because they had no choice. The Internet changes the relationship between application and content. To successfully design for the web you need to be able to influence your customers to choose your content from your site. Your electronic commerce application is merely the means for them to do so, rather than an application that is forcing them to do so. CoRAD's creative and cognitive disciplines come into play in creating an application with content that customers will choose to view. This is done using a five step process as shown in Figure 11-1.