M. M. Lehman. On understanding laws, evolution and conservation in the large program life cycle. Journal of Systems and Software, 1(3):213--221, 1980.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... however, would have come as a surprise had it not been anticipated by the 70s and 80 interpretation of the initial OS 360 observations, their subsequent phenomenological interpretation and the encapsulation of the observations and their interpretations in a set of laws of software evolution [3,4,5,6,13] prepared the investigators for such commonality. Thus the FEAST 1 results were seen as further support for six of the eight laws and supported many of the other conclusions that had been reached. The new evidence did, however, suggest some minor changes to the wording of the laws [15] While, ....

Lehman MM, On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle, J. of Sys. and Softw., v. 1, n. 3, 1980, pp. 213 - 221

....being used in the evolution process. From the point of view of the software engineer they were therefore to be viewed as laws. The first three of these laws were formulated in the mid seventies [leh74] and discussed in greater detail in 1978 [leh78] Two further laws were introduced in 1980 [leh80a]. A sixth was introduced in a subsequent footnote [leh91] The remaining two while publicly discussed have only recently been 9 4 97, 5:11 pm 3 mml565[papers] 3 References identified by a in the listing are reprinted in [leh85] published [leh96c] As restated 4 explicitly below the laws ....

* id., On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle, J. of Sys. and Software, v. 1, n. 3, 1980, pp. 213 - 221

....of the interaction between all the entities. Overlooking these may lead to inappropriate decisions. More generally, such decisions cannot be taken on the sole basis of technological and economic factors. As for many others areas, the problems addressed are of sociotechnological economic character [8,12]. Thus the ensuing discussion assumes that in resolving the software replacement issue, and as part of the economic assessment, relevant social, technological and business factors are also considered. And in considering them, it must be noted that the latter are also changing and evolving. 2 ....

....is interpreted in terms of the models and vice versa and expressed in a formal statement or descriptive text. Understanding of the observed behaviour, the models and the formal statement or descriptive text are then refined and or extended in an iterative process of successive refinement [12]. The laws were numbered in the order of their formulation. They have been modified over the years as understanding of the phenomena encapsulated in them has advanced [7,10,14,15] The current text of the laws is presented in the appendix (Table 1) though definitions of the concepts involved and ....

*id, On Understanding Laws, Evolution and Conservation in the Large Program Life-Cycle, Journal of Systems and Software, Vol. 1, No. 3, 1980

....of software evolution 1 were formulated in the mid seventies [leh74] arising from analysis of data first acquired during a study of the IBM programming process [leh69] 2 . These three were discussed in somewhat greater detail in 1978 [leh78] Two further laws were introduced in a 1980 paper [leh80a] with the sixth introduced in a footnote [leh91] The remaining two have been discussed in presentations but are published here for the first time. All relate specifically to E type systems [leh80b] that is, broadly speaking, to software systems that solve a problem or implement a computer ....

id., On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle, J. of Sys. and Software, v. 1, n. 3, 1980, pp. 213 - 221

....The average effective global activity rate in an evolving E type system is invariant over product lifetime. V 1980 Conservation of Familiarity As an E type system evolves all associated with it, developers, sales personnel, users, for example, must maintain mastery of its content and behaviour [leh80a] to achieve satisfactory evolution. Excessive growth diminishes that mastery. Hence the average incremental growth remains invariant as the system evolves. VI 1980 Continuing Growth The functional content of E type systems must be continually increased to maintain user satisfaction over their ....

* id., On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle, J. of Sys. and Software, v. 1, n. 3, 1980, pp. 213 - 221

....characteristics similar to those of OS 360 [16] The growth trend ripple as in figure 1, for example, is reminiscent of that of OS 360 as in figure 2. It was, of course, this ripple that first suggested the presence of feedback control. Moreover, the laws of software evolution as previously stated [14, 16, 20, 21] are upheld [22] or rather, not negated, by the data. There is also strong evidence [18] that a controlling internal dynamics develops over the early releases, as in figure 3. The E parameter of that figure is the constant of Turski s inverse square growth model [18] The plot shows that data ....

Lehman M M, On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle, J. of Sys. and Softw., v. 1, n. 3, 1980, 213 - 221

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M. M. Lehman. On understanding laws, evolution and conservation in the large program life cycle. Journal of Systems and Software, 1(3):213--221, 1980.

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*LEHMAN, M.M.: 'On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle,' J. of Sys. and Software, 1980, 1, (3), pp. 213-221

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Lehman MM, On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle, J. of Sys. and Softw., v. 1, n. 3, 1980, pp. 213 - 221

No context found.

id., On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle, J. of Sys. and Softw., v. 1, n. 3, 1980, pp. 213 - 221

No context found.

Lehman MM, On Understanding Laws, Evolution and Conservation in the Large Program Life Cycle, J. of Sys. and Softw., v. 1, n. 3, 1980, pp. 213 - 221

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