[Moims-dai] MOIMS DAI - OAIS Interoperability Framework - Notes and Comments - Tuesday 9/17/19

Hughes, John S (US 398B) john.s.hughes at jpl.nasa.gov
Sat Sep 21 16:35:53 UTC 2019

Hi all,

Here are some notes and a brief summary of the discussion items from our Tuesday 9/17/19 teleconference. Please feel free to comment and correct as necessary.


1)      Introduction and Scope - The document "Draft introductory statements for OAIS Interoperability Framework standard" written by  David Giaretta 20190726, was accepted as a succinct statement of scope for the OAIS-IF Blue Book. Mike Kearney also noted that the draft Blue Book's existing "Introduction and Scope" section contains the standard "boiler plate" for CCDSD documents. It was decided that David's focus on Interfaces and Services would guide further development of the Blue Book and over time it will be integrated into the existing "Introduction and Scope" section of the Blue Book.

2)      Accessing "Descriptive Information" from an OAIS - A question was posed as to how a Consumer (possibly another OAIS) obtains information from an OAIS about its holdings, primarily the AIPs it manages. For example, how would Archive B get the <Descriptive Information> for the AIPs in Archive B. This led to a number of discussion items.

a.       The  search/access component of the OAIS-IF must be limited to the most general level. Details including search protocols, query languages, etc are too varied and complex to be addressed now.

b.       However the OAIS Information Model (IM) must be known or be made accessible for potential Consumers to discover the "names" of the "items" in the archive that are accessible.

                                                               i.      By definition the OAIS-RM IM provides the most basic named items. (e.g., Information_Package, Information Object, Provenance_Information, etc.)

                                                             ii.      For a domain specific OAIS, a mechanism should be available for accessing domain specific extensions to the  IM. (e.g., the PDS4 Product_Observational and Product_Context.)

c.       All information distributed out of the OAIS is distributed as an Information Package.

                                                               i.      Are all Information Packages distributed from an OAIS considered to be DIPs?

                                                             ii.      The consumer must have access to Representation Information for each Information Package.

d.       What can be the contents of a distributed Information Package?

                                                               i.      Ideally there should be no limit on the type of information that can be included in a distributed Information Package.

                                                             ii.      By definition the content may be any or a derivation of any AIP(s) in the OAIS.

                                                           iii.      Descriptive Information used to support the finding, ordering, and retrieving of OAIS information holdings should be made available.

                                                           iv.      Finding Aids should be made available. - If the Finding Aid is a process then it could be distributed as serialized code)

                                                             v.      ...

e.       This leads to the question, what are the OAIS-IM class(es) and method(s) that are responsible for Information Object management, for example Description Information?

                                                               i.      In other words how are Information Objects that are not components of an AIP managed?

                                                             ii.      How are these Information Object accessed by Consumers?

f.        Since all AIPs (Information Objects) need to be registered, some type of Information Object registry should exist.

                                                               i.      An Information Object registry seems implicit in the definition of the Data Management functional entity.

3)      A Vision

a.       Assume that there exists a Consumer that has very limited knowledge about an archive other than it conforms at some level to the OAIS-RM and has a very basic access/retrieval protocol.

b.       The Consumer should be able to request a series of Information Objects from the archive and "bootstrap" themselves up to a level where they have sufficient knowledge to effectively interact with the archive.

                                                               i.      What basic protocol(s) are required?

                                                             ii.      The OAIS IM class names and definitions need to be readily accessible.

                                                           iii.      How does the Consumer access the discipline extensions to the OAIS IM (class names and definitions)?

                                                           iv.      How does the Consumer access the abstraction layer (class methods)?

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