%0 Journal Article %1 lehman76 %A Belady, L. A. %A Lehman, M. M. %D 1976 %I IBM %J IBM Systems Journal %K evolution software %P 225--252 %T A model of large program development %U http://domino.research.ibm.com/tchjr/journalindex.nsf/495f80c9d0f539778525681e00724804/24c3ab476966d22d85256bfa00685ad5?OpenDocument %V 3 %X As a need for a discipline of software engineering has been recognized, the design, implementation, and maintenance of computer software has come into the forefront. The formulation of concepts of programming methodology, exemplified by Dijkstra's structured programming,' strikes at the roots of the problem. The realization is that a program, much as a mathematical theorem, should and can be provable. Recognition that a program can be proved correct as it is developed and maintained,' and before its results are used, may ultimately change the nature of the programming task and the face of the programming world. Clearly these developments are of fundamental importance. They appear to point to long-term solutions to problems that will be encountered in creating the great amount of program text that the world appears to require. But even though progress in mastering the science of program creation, maintenance, and expansion has also been made, there is still a long way to go.

@article{lehman76, abstract = {As a need for a discipline of software engineering has been recognized, the design, implementation, and maintenance of computer software has come into the forefront. The formulation of concepts of programming methodology, exemplified by Dijkstra's structured programming,' strikes at the roots of the problem. The realization is that a program, much as a mathematical theorem, should and can be provable. Recognition that a program can be proved correct as it is developed and maintained,' and before its results are used, may ultimately change the nature of the programming task and the face of the programming world. Clearly these developments are of fundamental importance. They appear to point to long-term solutions to problems that will be encountered in creating the great amount of program text that the world appears to require. But even though progress in mastering the science of program creation, maintenance, and expansion has also been made, there is still a long way to go.}, added-at = {2006-09-18T06:26:07.000+0200}, author = {Belady, L. A. and Lehman, M. M.}, biburl = {https://www.bibsonomy.org/bibtex/27b6ab86578f686ab20b5e3e6fbc3a444/neilernst}, citeulike-article-id = {658246}, comment = {- seminal work on OS/360 and evolution - mentions Laws, which are more appropriately hypotheses or theories - not really statistically relevant, since this is really a case study. - map 4 relationships: modules changed, Release number (sequential, not clear if it discriminated btw minor and major versions), release interval in days, system size in modules, and complexity (modules changed over total modules). - law 1 - a system that is 'used' undergoes continuing change - law 2 - the unstructuredness (entropy) of a program increases (linearly/exponentially?) with time unless maintenance is done - law 3 - growth trends have well-defined long range trends - given that "complete and unambiguous specifications of changes or additions to be made are not normally achieved or even achievable", testing is required. Testing only shows deviation from expectation, not correctness, therefore, upon release the "system is suddenly exposed to an environment in which the expected behaviour and actual usage may differ from that to which the system was exposed" in its design and test phases. (p.234)}, description = {Not previously uploaded}, interhash = {108ae81426834aca7a63c9b95da75370}, intrahash = {7b6ab86578f686ab20b5e3e6fbc3a444}, journal = {IBM Systems Journal}, keywords = {evolution software}, pages = {225--252}, priority = {0}, publisher = {IBM}, timestamp = {2006-09-18T06:26:07.000+0200}, title = {A model of large program development}, url = {http://domino.research.ibm.com/tchjr/journalindex.nsf/495f80c9d0f539778525681e00724804/24c3ab476966d22d85256bfa00685ad5?OpenDocument}, volume = 3, year = 1976 }