Prototyping helps users get design satisfaction: 4GL tools are useful for the task, but structured methods needed for programs to be maintainable - fourth-generation language programming tools - includes related article on Sterling Software Inc - CASE: Prototyping/4GL Tools - buyers guide

Software Magazine, April, 1991 by Mary Alice Hanna

PROTOTYPING HELPS USERS GET DESIGN SATISFACTION

The problem does not often arise: how to produce a dictionary of Old English from a corpus of over 3,000 manuscripts. The editors of this dictionary, based at the University of Toronto in Ontario, decided they needed some unusual software.

Microlytics, Inc., Rochester, N.Y., also faced a need for unusual software. Microlytics, a wholly owned subsidiary of Selectronics, Inc., also of Rochester, markets the WordFinder Thesaurus, the Physician's Desk Reference, The Bible and several other dictionary-like works that have been mapped onto hand-held devices. The challenge was to minimize the space required by these works, and maximize the efficiency of the look-up algorithms so that the customer could access the entries quickly and easily.

The software solution for both cases was found through a design technique called prototyping. In many instances, prototyping today is performed with fourth-generation language (4GL) tools. The focus of 4GL tools on end-user programming has evolved into a sophisticated development environment that can also be of great value during the traditional design phase of a project.

The importance of prototyping is growing, and the tools available for prototyping are becoming more sophisticated. This is mainly due to the growth of Case in the development environment. The ability to produce an easily modifiable application in a short time is, after all, one of the main goals of the Case industry.

Several definitions of "prototype" are in use today. According to CompuServe Data Technologies of Cambridge, Mass., a subsidiary of CompuServe, Inc. of Columbus, Ohio, a prototype is a skeletal software version of a program or an application. It may be used to demonstrate the application before it is completed, allowing potential users to provide feedback about its usability and functionality. A prototype can be created and later discarded, or modified/built upon to result in a finished product.

"Prototyping provides a set of mechanisms that people can use to develop systems," said Jerrold Grochow, vice president of American Management Systems, Inc., Arlington, Va., a software development firm. "But how successful they are depends on how well they plan and understand, and then properly do the required work."

Core Foundation Software, AMS' product, provides Cobol-based code, which is the basis of many systems the firm writes.

It is useful for people who are not accustomed to online, interactive systems to be able to have a prototype of a user interface available quickly. "What makes prototyping successful is having the user and the developer knowledgeable about what is to be developed," Grochow said.

One example of a prototyping tool is the CompuServe System 1032 Application Facility. According to Kevin Fuller, product line manager at CompuServe Data Technologies, "CompuServe's System 1032 Application Facility is a screen-based package intended to build screen-based applications. System 1032/AF generates default screens, options and reports." He continued, "The prototype quickly and easily gives the developer something that looks like a finished system, and yet only takes a short time to prepare."

AF's prototype does not have to be thrown away after the design phase is complete. It can be tailored and shaped into the final application. The "application build" step can be run interactively or in batch mode. According to CompuServe, this makes it easy to move back and forth between development and user run mode, thus enhancing ease of modification. 4GL code is produced, and the resulting application can run on any VAX. The number of users supported is said to depend only on the application and CPU size.

Fuller said, "People are largely interested in doing prototyping when user interface issues are involved, and they simply cannot be resolved on paper."

Harold Kurt, analyst/programmer at Kaiser Permanente of the Northwest in Portland, Ore., utilizes CompuServe's software to develop an application quickly, and then modify it to more accurately reflect the customer's needs. The prototype is the initial version of the full system.

Coming from the user side of the Health Maintenance Organization (HMO) business, Kurt used System 1032/AF to create a prototype of a system for the rapidly expanding Industrial Medicine Department, allowing the users to "touch and feel the system, and then altering it to be exactly what they needed." About 80% of the business needs of that department was developed by one person in a three-month timeframe.

Despite Kurt's complaint that the Screen Painter feature could be more streamlined, System 1032/AF at Kaiser Permanente is popular: Up to 50 statistical analysts are writing their own applications with it. Kurt said that nonprogramming users can be trained in about six months. In many instances, this is the typical use of 4GL products, and the line between this type of iterative system development and the "classical" concept of prototyping is a rather thin one.