Abstract
Many client users expect that the latest specifications of both their existing system and the application programs be exhaustively described in the design documentations. However, it is often the case that such a client user does not find as great importance in the stringent management of the updated design documentations as in the performance quality of the platform system and the related application programs. In particular, when the client user uses a "legacy" platform, it is highly likely that the related application programs have undergone repetitive addition of new features over the long period of use, and that, consequently, such changes or modifications have failed to be fully described or accurately recorded in the latest design documentation of the application programs. In this paper, I will introduce a method for a client user to smoothly conduct "from-scratch" development of a new application program with equivalent features to those of the counterpart program running on the previous legacy platform. By this method, the client can effectively implement migration to a new system without losing the performance features and the interoperability of the previous application programs, which is usually unattainable unless the complete updated information of the application programs running on the legacy system is available for the development process.
