A combination of circumstances and operations used as a guideline for development (or selection) of a Configuration Item (CI). The combination might, or might not, contain one or more sequences.
DRM’s can vary widely in their complexity. They might (or might not) be used as a source of significant Functional Analysis for development efforts, and might (or might not) be used as the basis for significant requirements analysis, including (but not limited to) Performance Requirements. It is possible for more than just one DRM to be formally identified on a single development project.
Although a DRM can identify (or merely allude to) one or more Environments, legacy practices make a firm distinction between the attributes of a DRM and those of an Environment: the Environment generally exists whether the specific DRM is executed or not1.
Footnotes- Of course, a gray area exists when “self-induced” environments are considered.[↩]