Abstract: Differences between both the code and documentation of a revised generation of software and a previous generation are compared by a digital computer with the intended revisions stored in a release file. When all discrepancies have been eliminated, and for the original generation of the software, actual impacts in the form of the locations in the program where one routine is called by another and where common statements and public variables are used, are compared with expected impacts stored in the release file. When all actual impacts have been identified, the revised software, or the original version in the case of newly created software, is stored in a library with the code and documentation paired, and with each revision of each unit identified for later retrieval and reconstruction of any software generation.