RE: 2167A Questions

[MMC/CS 609-338-2922/8-794-2922 <ASTARR@CAYMAN.VF.GE.COM>]

>Date: 21 Jul 93 20:01:59 GMT
>From: agate!howland.reston.ans.net!darwin.sura.net!source.asset.com!vand@ucbva
x.Berkeley.EDU  (Laurence VanDolsen)
>Subject: Re: 2167A Questions
>Message-ID: <1993Jul21.200159.32712@source.asset.com>

>In article <1993Jul21.143352.17146@newshost.lanl.gov> hines@paloverde.lanl.gov
 writes:
>
>In article 26847@sctc.com, aldrin@sctc.com (John Aldrin) writes:
>> ...  The concept of what the definition of CSU's, CSC's and
>>CSCI's are somewhat vague.  I was hoping those of u who have dealt with
>>this standard may be able to provide good definitions of CSU's, CSC's and
>>CSCI's.
>
>Anyway, we intend to shoot towards the new standard rather than tie ourselves
>in knots with 2167A. Our approach will be to "tailor 2167A towards the new sta
ndard"
>(whatever that means).
>>>Mr Van Dolson's response to the above was good - I add my 2 
cents.

CSCI/CSC/CSU:
1.  Look at CSCI/CSC/CSU like Book/Chapter/Paragraph.  You 
declare something a paragraph because it has sentences which 
convey a thought; chapters are groupings of paragraphs addressing 
some aspect of a theme; the book addresses the entire theme.  Your 
chapter may be my book - there is no *right* answer.
2.  When defining CSCIs, think about how you are going to be 
doing configuration management (documenting changes, bumping up 
rev levels, etc).  If you have defined 2 CSCIs and think 
modifying one will almost always require modification of the 
other, they should probably be merged.
3.  For a DoD job, it is better to *err* with too few rather than 
twoo many CSCIs - CSCI documentation is a major cost driver.
4.  If you are working Ada, many people declare a package to be a 
CSC and procedures to be CSUs.  For a DoD job, you often have to 
report progress at the CSC level so it is important to group CSUs 
or you'll get in a tight loop writing progress reports on why 
you are late because you are always writing progress reports.
5.  When declaring a CSC, plan on testing all its CSUs at the 
same time.  This should save you a lot of drivers and stubs.

2167A:
1.  Agree that it is a pretty good framework for guiding projects 
- but it must be intelligently tailored to your project.
2.  If your customer thinks Moses brought 2167A down on a second 
set of stone tablets, find a good sector mutual fund that 
concentrates in pharmaceuticals - look for holdings in 
manufacturers of Maalox, Aspirin, etc.
3.  2167A requires traceability of requirements to CSUs.  Type 1 
customers require this; Type 2 customers go for the CSC level.  
Everyone should have a Type 1 customer so they appreciate Type 2. 
One of the purposes of requirements allocation is to establish 
the basis for test plans.  Test Plans/Procedures are usually 
written to test CSCs rather than CSUs  It's similar to trying to 
understand the significance of a paragraph - you normally need to 
read the chapter to find out the significance of a paragraph and 
whether the paragraph hits its mark.

Allen L. Starr, Martin Marietta Corp/Communications Systems/AE-2E
One Federal Street, Camden, NJ 08102  astarr@carib.vf.ge.com
phone:  609-338-2922; fax: 609-338-4686
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