A-Spec
A type of specification covering an entire complex system, or a major portion of one. As far as I can tell, the term appears to have originated with MIL-STD-490. A good statement of purpose is in DI-CMAN-80008: the A-spec was used to define and partition the requirements allocable to all or part of a system…... read more
Addendum Specification
Exactly as it sounds: a piece of a specification which, for whatever reason, has not been published as a physical part of the main document body. An addendum does not stand on its own, but is part of the specification, and its provisions carry the same force. Examples of addenda include classified material (which can... read more
B-spec
Short for “Type B Specification” in the MIL-STD-490 framework. A development specification.
C-Spec
A Product/Fabrication specification in the MIL-STD-490 framework, collecting (whether directly or by reference) the acceptance requirements for a single design, which may (or may not) be the only design for a single CI. It is both possible and reasonable for a single B-spec to have more than one C-spec, if multiple designs are being competed... read more
Detail Specification
In the MIL-STD-490 context, either of the following: A comprehensive set of technical requirements allocable to a given CI without reference to General Specification(s) A set of requirements uniquely allocable to a given CI (sometimes referred to as a “specification sheet”, although they could take book form) plus references to the applicable General Specification(s)
Development Specification
A type of detail specification containing the technical requirements for the design and verification of a CI. Contrast with Product/Fabrication Specification.
General Specification
In the MIL-STD-490 context, a type of specification containing the technical requirements generically applicable to more than one CI or class of CI, avoiding the repetition of requirements common to more than one detail specification or set of addendum specifications. These specifications were an early (and effective) implementation of concepts that Object Oriented software engineers... read more
Interface Requirements Document (IRD)
A prescriptive ICD addressing the requirements for the as-yet-un-designed items. Referred to in the legacy as a “Part I ICD”.
Interface Requirements Specification (IRS)
A type of specification unique to Software Systems Engineering, where the “interface” was originally a component (e.g., a Graphical User Interface), but that has been generalized to combine the concepts of ICD and Specification which were, in the hardware legacy, two completely different things.
MIL-S-83490
A now-canceled standard for specification practices. The immediate predecessor to MIL-STD-490. MIL-S-83490 used a “Part I/Part II” specification nomenclature, which exactly corresponded to the more recent “B-spec/C-Spec” nomenclature of MIL-STD-490.
Part I Specification
A legacy term (MIL-S-83490) for a development specification.
Part II Specification
A legacy term (MIL-S-83490) for a product/fabrication specification.
Prime Item
Anecdotally, a CEI on a Prime Contract and, therefore, the subject of a Type B1 specification in accordance with MIL-STD-490. Lower-order CI’s could also be CEI’s (especially late in the contract, as maintenance items were formally identified), but these (the Prime Items) were considered the heavy-hitters.
Product/Fabrication Specification
A type of specification associated with a specific Part Number or group of Part Numbers; sometimes referred to as a “C-spec”. The requirements address whether an acceptable “instance” of a design has, in fact, been produced. In many cases, this type of specification was little more than a reference to a CEI’s identifying drawing (or,... read more