[Moims-dai] OAIS-IF Document Tree

[kearneysolutions at gmail.com]

Today's telecon had a soul-searching discussion of what an ADD (Architecture
Description Document) is, and what the Blue book that we're currently
developing is.  Steve described it's tendency towards focusing on the
details of the Archive Abstraction Layer, and hence we began to discuss
whether the content currently in the blue book is really ADD material or AAL
Blue Book material.  This led to a discussion where I said we should have a
document tree, so naturally I got the action to build it.  

 

Attached is a PPT with a first notional cut at a document tree.  I'll also
suggest that a Doc Tree figure should actually be in the ADD, or even
perhaps the OAIS Reference Model document (next revision, of course).  This
ADD after all, is intended to be the ADD for the OAIS-IF, not an overall
OAIS architecture.  The OAIS-IF ADD is subordinate to the OAIS RM, not the
other way around.  I did not try to include the shadow-organization of an
ISO Doc Tree.  To be complete we should probably do that, and spell out
acronyms.  Right now I consider this a working document for us insiders.  

 

A few comments are in the notes of the PPT charts.  Two additional charts
from IPELTU and our CMC material are added for reference.  

 

Some background on ADDs:  There is only one other in CCSDS, for Cross
Support, the CCSS-ADD, and it is here:

https://public.ccsds.org/Pubs/901x0g1.pdf

It is a green (informative, not normative) book, and it has a companion
Magenta book (an ARD - Architecture Requirements Document).  The ARD is not
in our plan.  We could conceivably have a magenta ADD that includes
normative requirements like an ARD.  

 

Some notable statements from the CCSS-ADD (relating them to our OAIS-IF
ADD):  

*	The foreword on page ii says:  The architecture described in this
document was developed based on the Cross Support Reference Model."  Our
counterpart statement is that our ADD is based on the OAIS Reference Model.

*	Section 2.1, page 2-1:  "The SCCS communications architecture
reference model described in this document establishes a common framework
that provides a basis for developing, providing, and using space
communications cross support services."  Our ADD does the same for Archive
Services.  
*	Section 2.2, page 2-1:  "This SCCS-ADD Green Book provides the
top-level description of the architecture elements of space communications
cross support."  Our ADD should provide the top-level description of the
architecture elements of the OAIS-IF.  Seems to me that "Top Level" includes
the entire UML chart that Steve has developed.  However, Steve made verbal
reference to focusing on the "gray/green boxes".  The document that focuses
on the abstraction layer should be the Archive Abstraction Layer Blue Book.
Our counterpart to the MAL <https://public.ccsds.org/Pubs/521x0b2e1.pdf> .  

 

So there's my notional Doc Tree, and how the ADD relates to it.  

 

   -=- Mike

 

Mike Kearney

Huntsville, Alabama, USA 

 

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