[Moims-dai] Telecon Notes?

Mark Conrad mark.conrad at nara.gov
Tue Jul 24 13:16:09 UTC 2018

Hi Don,

"I believe an Archive *implemented primarily for the preservation of
physical books (Content Data Objects) understandable to the associated
Designated Community* would be fully justified in not conjuring up
information, to be called RepInfo, just to meet someone’s concept of a best
practice or a mandatory requirement for some type of certification."

1. It sounds to me like you are describing a* library* - not an Archive.
The former is not in the scope of the OAIS Reference Model.

2. In 1.1 Purpose and Scope:

"In this reference model there is a particular focus on digital
information, both as the primary forms of information held and as
supporting information for both digitally and physically preserved
materials.  Therefore, the model accommodates information that is
inherently non-digital (e.g., a physical sample), but the modeling and
preservation of such information is not addressed in detail.  This
reference model:

– provides a framework that may be expanded by other efforts to cover Long
Term Preservation of information that is NOT in digital form (e.g.,
physical media and physical samples);"

On this basis, I would say that your example is out of scope for the OAIS
Reference Model.

I believe the examples that you have given in messages relevant to this
thread have been edge cases at best, and more likely are out of scope for
the OAIS Reference Model. I do not believe they justify making
Representation Information optional. Doing so would mean that repositories
would be free to not add sufficient Representation Information as the needs
of the Designated Community or its Knowledge Base changed over time. This
is one of the most critical parts of Long Term Preservation. It would also
throw backward compatibility out the window.


Mark Conrad
NARA Information Services
Systems Engineering Division (IT)
The National Archives and Records Administration
Erma Ora Byrd Conference and Learning Center
Building 494, Room 225
610 State Route 956
Rocket Center, WV  26726

Phone: 304-726-7820
Fax: 304-726-7802
Email: mark.conrad at nara.gov

On Sun, Jul 22, 2018 at 9:27 AM, D or C Sawyer <Sawyer at acm.org> wrote:

> Dear all,
> I would like to return to this point in the discussion on David’s proposal
> as I think David has made some valuable points that may get lost.  I have
> not heard anyone disagree that, under some circumstances, a physical book
> does not need RepInfo.  As an example, I believe an Archive implemented
> primarily for the preservation of physical books (Content Data Objects)
> understandable to the associated Designated Community would be fully
> justified in not conjuring up information, to be called RepInfo, just to
> meet someone’s concept of a best practice or a mandatory requirement for
> some type of certification.  There may, or may not, eventually be a
> requirement for the addition of real RepInfo to such CDOs.  This is all
> about practical implementations.
> In contrast, the OAIS RM is a conceptual model and its AIP is the key unit
> of information that is being preserved.  The AIP is defined to include
> RepInfo with the CDO, forming Content Information, as this Content
> Information entity is of central importance to the preservation of digital
> information.  I see no reason to alter this Content Information definition
> and I don’t believe anyone is proposing to do so. At the same time I have
> no problem recognizing that some implementations, such as that given in the
> Archive example above, may have an AIP whose Content Information is the CDO
> alone. This simply reflects local, practical, reality. The example
> highlights the possible differences between a concept and local reality.
> In my opinion, when there is good justification, such differences should
> not be of major concern. David’s proposal for the OAIS RM regarding
> implicit and explicit RepInfo is designed to acknowledge this reality.
> While I had some objection to the ‘implicit’ part of his proposed wordingl,
> I firmly support the attempt and believe some appropriate words can be
> found. It should not take a lot of discussion to find such words if there
> is agreement on the objective.
> When the OAIS RM uses the phrase ‘Representation Information’, it should
> mean the same concept everywhere in the document.  It should not also stand
> for some made up sentence just to satisfy a conceptual information
> category.  Therefore I think John’s second paragraph below is properly
> understood as an implementation view where he thinks an actual AIP should
> always have a RepInfo category.  One could consider this a possible best
> practice, but personally I would not go that far.  Discussion of this
> particular view  makes sense in the context of ISO 16363.  As for the OAIS
> RM, again I support David’s attempt to clarify that some AIP
> implementations may not need explicit RepInfo *as it has been defined in
> the OAIS RM.*
> Cheers-
> Don
> On Jul 17, 2018, at 4:11 AM, John Garrett <garrett at his.com> wrote:
> Hi,
> I’m also uncomfortable with the updated conformance.  I also feel that it
> would be a significant change and I think it would open up a door to keep
> expanding the conformance requirements.  I would prefer to try to update
> Section 2 a bit and keep the Conformance section the same.
> Also I’m not on board with having original data objects in an AIP that do
> not require RepInfo.  I think if we have a physical book in local language,
> we should still require RepInfo as we form the AIP.
> Peace and joy,
> -JOhn
> *From:* MOIMS-DAI [mailto:moims-dai-bounces at mailman.ccsds.org
> <moims-dai-bounces at mailman.ccsds.org>] *On Behalf Of *D or C Sawyer
> *Sent:* Monday, July 16, 2018 11:36 PM
> *To:* MOIMS DAI List <moims-dai at mailman.ccsds.org>
> *Subject:* Re: [Moims-dai] Telecon Notes?
> Dear All,
> The proposal for section 1.4 (conformance) is to include section 4.2
> information modeling for conformance. This is a considerable increase in
> requirement which originally we did not feel comfortable requiring.  This
> is not backward compatible so it may be controversial in the larger
> community.
> The proposal for section states that an explicit or implicit lack
> of Representation Information can be regarded as a sufficient expression of
> meeting a Representation Information requirement. There is a bit of a
> problem with ‘implicit’ as it could be used as justification for no
> Representation Information when in fact it was needed.  Perhaps the
> ‘implicit’ should be dropped?
> However this kind of statement on Representation Information is also true
> for selected components of PDI (which can also be recursive), depending on
> the judgement of the Archive in support of the associated Designated
> Community. I believe some appropriate text is needed for PDI as well,
> particularly if 4.2 is now to be part of conformance.
> Once again I will be unable to participate in the Tuesday DAI telecon as
> I’ll be working with my contractor.
> Cheers-
> Don
> On Jul 16, 2018, at 8:00 AM, David Giaretta <david at giaretta.org> wrote:
> I have added a suggested change  - see http://review.oais.info/
> show_bug.cgi?id=236
> Also, in the resolution of http://review.oais.info/show_bug.cgi?id=35 there
> was an action in comment 4 to create a related suggested change which I
> have done in http://review.oais.info/show_bug.cgi?id=237
> ..David
> *From:* MOIMS-DAI <moims-dai-bounces at mailman.ccsds.org> *On Behalf Of *David
> Giaretta
> *Sent:* 15 July 2018 19:24
> *To:* 'MOIMS-Data Archive Interoperability' <moims-dai at mailman.ccsds.org>
> *Subject:* Re: [Moims-dai] Telecon Notes?
> Hi Don and others in MOIMS-DAI
> It looks as if we can reach a conclusion – see below for some general
> suggestions. I will try to suggest something specific on the review site.
> Regards
> ..David
> -----Original Message-----
> From: MOIMS-DAI <moims-dai-bounces at mailman.ccsds.org> On Behalf Of D or C
> Sawyer
> Sent: 13 July 2018 14:18
> To: MOIMS DAI List <moims-dai at mailman.ccsds.org>
> Subject: Re: [Moims-dai] Telecon Notes?
> Hi David, et al.,
> I mostly agree with your comments, but see below.
> > On Jul 9, 2018, at 7:12 AM, David Giaretta <david at giaretta.org> wrote:
> >
> > Hi all
> >
> > I missed the call on which these notes report, but I must make a few
> comments which I am sure I would have made in the meeting.
> >
> > In summary Don's arguments about the Information Model seem to derive
> from examples of some specific Data Objects, without explicit consideration
> of the Designated Community, which I argue is misleading, and can be
> addressed by adding text to the standard to address such "edge cases", as
> discussed next.
> During the subject telecon it was mentioned that a CDO with no needed
> Representation Information depended on the Designated Community. The point
> of the discussion was to note that this is a real example. It could be
> thought of as an ‘edge case’, as you say, or perhaps the modeling and text
> should be improved to bring it into compliance.
> Yes we definitely should add text to explain this, perhaps in the
> discussion in section Representation Information.
> >
> > The argument about whether or not a Data Object needs Representation
> Information in order to be understood is misleading in that, as I responded
> in a previous email, it depends on the Designated Community. In other
> words, if the Data Object is a piece of paper written in English, and
> members of the Designated Community can read and understand English then
> there is no need for an explicit English dictionary because the Designated
> Community's Knowledge Base includes that.
> >
> > However, if the Designated Community were to be defined as readers of
> Chinese then Representation Information such as an English Dictionary would
> be needed. So, if one claims that this piece of paper does not need
> Representation Information then that is in the context of a Repository's
> definition of a specific Designated Community.
> >
> > So in general modelling terms the OAIS Information Model is right - a
> Data Object needs Representation Information in order to be
> used/understood. However there may be some specific instances where, for a
> specific Designated Community, explicit Representation Information is not
> needed.
> >
> > In modelling terms, I would regard cases such as English written on
> paper to be read by English readers as an "edge case" and to be consistent
> in such edge cases one should say that the Representation Information is
> the statement that "for the specific Designated Community no additional
> explicit Representation Information is currently needed". As far as I can
> see this would make the model complete and consistent. We could add some
> wording to the discussion of Representation Information and Designated
> Community to make this clear.
> >
> > In terms of the idea of OAIS being only a "communications framework" -
> yes it is that, especially the Functional Model, but it also provides
> something more, namely guidance of what one needs in order to preserve
> digitally encoded information, and OAIS lays these out in terms of
> conformance. Thus, the repository needs an AIP with all its components; it
> needs to undertake all the Mandatory Responsibilities.
> Yes on the Mandatory Responsibilities, but on the ‘AIP with all its
> components’ there is considerable ambiguity.  The information modeling
> conformance only addressed the Information Object and the Information
> Package as given in Section 2.2. The Information Package is broken into
> SIPs, AIPs, and DIPs,  It is clear that SIPs and DIPs may not contain all
> the Representation Information or PDI.  The implication (not stated) is
> that the AIP does contain all the Representation Information and PDI.
> Certainly it does conceptually.  However the conformance section (1.4)
> addresses an actual Archive.  The example above raises the conformance
> issue for an Archive that only preserves hardcopy documents, with no
> Representation Information, yet still fully understandable to its
> Designated Community, Maybe it also finds it doesn’t need all the PDI.  Can
> it still claim to be OAIS conformant? I would say ‘yes’ as long as it is
> making a reasonable argument for not having all the components of the
> section 2.2 information models.  Note also that none of the modeling in
> section 4.2 is required for OAIS RM conformance.  Given that OAIS RM
> conformance has sometime been a topic of concern to others as well as to
> this working group, I recommend it be clarified.
> I agree – we should make it clear that 2.2 and 4.2 are both included in
> the Mandatory Responsibilities and also in the Conformance section. In
> section 2.2 we say “While formal modeling of information is provided in
> section 4, some key concepts are provided in this subsection” but this
> should be expanded also.
> >
> > I realise that to some readers all this may seem like a very abstruse,
> uninteresting discussion. However, it IS important because there will be
> times when repository staff will come across puzzling cases and we need to
> make sure, as far as humanly possible, that OAIS provides useful, correct
> and consistent guidance when read carefully.
> Yes, we should want the OAIS RM to be as clear and unambiguous as we can
> make it.
> Yes I think we have relied on some implicit connections that should be
> made explicit.
> Cheers-
> Don
> >
> > Hope that helps
> >
> > ..David
> >
> >
> >
> > -----Original Message-----
> > From: MOIMS-DAI <moims-dai-bounces at mailman.ccsds.org> On Behalf Of John
> Garrett
> > Sent: 07 July 2018 05:55
> > To: 'MOIMS-Data Archive Interoperability' <moims-dai at mailman.ccsds.org>
> > Subject: [Moims-dai] FW: Telecon Notes?
> >
> >
> >
> > -----Original Message-----
> > From: Don Sawyer [mailto:topcottageguys at gmail.com
> <topcottageguys at gmail.com>] On Behalf Of D or C Sawyer
> > Sent: Monday, July 2, 2018 8:18 AM
> > To: John Garrett <garrett at his.com>
> > Cc: Hughes, John S (398B) <John.S.Hughes at jpl.nasa.gov>; Mark Conrad <
> Mark.Conrad at nara.gov>
> > Subject: Re: Telecon Notes?
> >
> > Hi John,
> >
> > I’ve made a few comments to your comments.  I think our differing views
> are pretty clear.  If you want to add some more comments, or not, I have no
> objections to your sending this out to the wider group.
> >
> > Cheers-
> > Don
> >
> >
> > _______________________________________________
> > MOIMS-DAI mailing list
> > MOIMS-DAI at mailman.ccsds.org
> > https://mailman.ccsds.org/cgi-bin/mailman/listinfo/moims-dai
> _______________________________________________
> MOIMS-DAI mailing list
> MOIMS-DAI at mailman.ccsds.org
> https://mailman.ccsds.org/cgi-bin/mailman/listinfo/moims-dai
> _______________________________________________
> MOIMS-DAI mailing list
> MOIMS-DAI at mailman.ccsds.org
> https://mailman.ccsds.org/cgi-bin/mailman/listinfo/moims-dai
> _______________________________________________
> MOIMS-DAI mailing list
> MOIMS-DAI at mailman.ccsds.org
> https://mailman.ccsds.org/cgi-bin/mailman/listinfo/moims-dai
> _______________________________________________
> MOIMS-DAI mailing list
> MOIMS-DAI at mailman.ccsds.org
> https://mailman.ccsds.org/cgi-bin/mailman/listinfo/moims-dai
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ccsds.org/pipermail/moims-dai/attachments/20180724/8e1de810/attachment.html>

More information about the MOIMS-DAI mailing list