When youve determined the specifications, and perhaps done a prototype program for the user , you can break the application down into all the steps necessary to accomplish that job.
For instance, printing a report of a sales analysis might be broken down into three programs: a requestor program, a selection program to retrieve the requested database information, and a print program to actually print the report.
These three steps constitute a typical request/extract and a summary-report print. The output report could also be a display screen as well as a printed report. Thats a typical end user request and applicationbreaking an end user report into three steps that would be required in terms of programs. A typical company will have hundreds of these request/extract/print applications to service the information needs of its many end users.