The designer only accesses and modifies a formal requirements document. Once the changes are complete, the entire system is built from scratch using the newly changed requirements. Since the designer only edits the requirements, it is like working only on the first phase of the traditional technological design model, The requirements serve as the complete specification and design of the system. The coding is automated by the software and can be proven to be correct since it was derived by a formal process. No testing needs to be done beyond testing to see if the entered requirements actually solves the intended problem.
Maintenance is as simple modifying the requirements and generating the system over again.
Modifying software using technological design is much more costly since any modification to the requirements may require months of tracking down all the affected systems through the later phases of the design process. The front end consisted of a menu and prompt driven interface that allows the programmer to access and edit specification fragments. It has also been used to build and maintain the OCIS system for the John Hopkins Oncology Center. The full OCIS system code, once generated results in a million line program. The number of people required to maintain and update it is small compared to most software systems this size.