Re: 2167A Questions

[Colin James 0621 <cjames@dsc.blm.gov>]

  
Several writers have classified Computer Software Configuration Item
(CSCI), Computer Software Component (CSC), and Computer Software Unit
(CSU), eg, respectively as book, chapter, and paragraph.   This is
not exact because a CSC may be composed of other lower level CSCs.
However a CSCI may not be composed of other CSCIs nor are CSUs
composed of other CSUs.
  
The confusion with these items seems to arise when designing and 
mapping them to Ada.  David Maibor, one of the principal authors of
DoD-STD-2167A/2168, makes the important point that CSCs may be
composed of other CSCs;  Donald Firesmith of Advanced Software 
Technology Specialists, Ossian, IN has invented a convenient methodology
of mapping design objects within the 2167A cycle to Ada objects in
general;  and I have invented a method, based on Jackson, of directly
mapping objects on a one-to-one basis from the requirements/specifications
phase into Ada implementation objects (known as Object Oriented Life
Cycle [OOLC]).  This decomposes specifications from users into objects
and operations, recomposes them into software requirements and
documentsion, maps these into the software design components of
Dod-STD-2167A, implements them directly into the language structures
of Ada-83, and traces quality assurance and configuration control for
managers according to Dod-STD-2168. (OOLC won't brush your teeth :-<  .)
  
In recent times, many other methods have attempted to address the 2167A
to Ada connection.  As I recall, Rational abandoned trying.  But there
are at least two successful methods, namely Firesmith's and mine.