S-Type Systems

A-B-C- D-E-F- G-H-I- J-K-L- M-N-O- P-Q-R- S-T-U- V-W-X- Y-Z

Identification

Definitions/Uses

1997
Reference	/Lehman, 1985a/ Software Evolution - Processes of Software Change /Lehman, 2000b/ Rules and Tools for Software Evolution and Management
Definition/ Use	In S-type programs the sole criterion of acceptability is correctness in the mathematical sense. Continuing change and growth, and hence, evolution over a series of versions or releases, appear to be inherent properties of E-type systems, and hence the importance of their study and of the laws that apply to them. S-type systems have their role, for example, as building blocks from which E-type systems are from.
1993
Reference	William Aspray interviews M. M. Lehmann
Definition/ Use	S-type programs are programs where the criterion of success is that the program satisfies its specification. This is a mathematical concept, and in my view the relevance of Dijkstra's approach is restricted to S-type programs. For such programs one's obligations are restricted to a demonstration that the program is correct relative to the specification. It says nothing at all about the specification. The criterion of success in creating an S-type program is that it is correct in a strict mathematical sense.

See also

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