SCM: a CM Antithesis

[From CM versus SCM]

CM and SCM are tightly related, because SCM is born from CM, as its antithesis.

• CM focuses on splitting the work, assigning tasks, and ensuring every resource has an owner.
• SCM focuses on sharing and validating contributions. Ownership is only temporary, a necessary evil, and must be released as soon as results get published.

• CM is about control (preventing things from happening in an other way than the one mandated).
• SCM is about management (making sense out of what happened, so that it could be e.g. reproduced).

• From the CM point of view, SCM is a restriction of CM: CM restricted (or applied) to Software.
• From the SCM point of view, it is CM which is a restriction, in at least two ways (CM is always available as part of SCM: control what you cannot manage):
  • SCM restricted to elements (first-order managed items), an arbitrary subset of the configuration items found in any given software configuration.
  • Change Management (a main focus of CM), is the (specific) control of differences born sequentially in time, a subset of the possible differences between members of a family.

• CM aims at producing, often from scratch. When it comes to identification, it will be satisfied with accumulation of data, such as in the definitions for SCM.
• SCM aims at maintaining, and tries to avoid to have to produce as much as possible. For it, identification is mostly a matter of discrimination, such as in ...this page.

I would add yet one pair: CM starts from an accounting perspective, SCM from a communications one. In other words, CM focuses upon the existence of static artifacts at the bottom of an hypothetical development process, whereas SCM focuses upon the meaning of the dynamic (evolving) result of the development. CM was of course developed in a situation in which there was nothing else but the static artifacts (no derived objects). SCM has to deal with a situation in which source code (the static artifacts) is only important for their authors, but merely disappears from the final products.

-- MarcGirod - 19 May 2003

This led to a discussion.