[Moims-dai] FW: Comments on your blog post.

Mark Conrad mark.conrad at nara.gov
Wed Feb 24 16:44:07 UTC 2016

Thanks, David. It will be interesting to see how he reacts.


Mark Conrad
NARA Information Services
The National Archives and Records Administration
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Email: mark.conrad at nara.gov

On Wed, Feb 24, 2016 at 10:42 AM, David Giaretta <david at giaretta.org> wrote:

> This is the email I sent to David Rosenthal at the same time as publishing
> the post.
> ..David
> *From:* David Giaretta [mailto:david at giaretta.org]
> *Sent:* 24 February 2016 15:41
> *To:* David S. H. Rosenthal (dshr at stanford.edu) <dshr at stanford.edu>
> *Subject:* Comments on your blog post.
> Dear David
> I’ve put the following text on the DPC forum about OAIS -
> http://wiki.dpconline.org/index.php?title=Comments_on_David_Rosenthal%27s_%E2%80%9CThe_case_for_a_revision_of_OAIS%E2%80%9D
> .  I hope it is a helpful contribution to the discussion.
> Regards
> ..David
> *Comments on “The case for a revision of OAIS”*
> From
> http://wiki.dpconline.org/index.php?title=The_case_for_a_revision_of_OAIS
> by David Rosenthal
> <http://wiki.dpconline.org/index.php?title=User:DRosenthal>
> *COMMENTS by David Giaretta on behalf of the working group responsible for
> OAISrevision*
> *The following contains comments to David Rosenthal’s posting “The case
> for a revision of OAIS” at *
> *http://wiki.dpconline.org/index.php?title=The_case_for_a_revision_of_OAIS*
> <http://wiki.dpconline.org/index.php?title=The_case_for_a_revision_of_OAIS>
> *.*
> *The normal process for ISO standards involves a review after 5 years,
> which means that OAIS is due for revision in 2017.   However, it is
> important to understand OAIS before proposing revisions. As indicated in
> the comments below, the case laid out is built on some fundamental
> misunderstandings of the standard, in particular not realising that OAIS
> provides a reference model as it very clearly states in the following way
> (see page 1-2): “This reference model does not specify a design or an
> implementation.  Actual implementations may group or break out
> functionality differently”.  *
> *The comments below (indented and in bold) seek to correct the statements
> in the original post.*
> *The official title of ISO 14721 is **Reference Model for an Open
> Archival Information System (OAIS)*
> <http://www.iso.org/iso/home/store/catalogue_ics/catalogue_detail_ics.htm?csnumber=57284>*.
> The role of a reference model is to provide abstract concepts and
> terminology by means of which concrete systems can described and analysed.
> A reference model is not of itself a standard against which concrete
> systems can be assessed for conformance, that is the role of criteria based
> on these concepts and terminology. In the case of ISO 14721 this role is
> performed by **ISO 16363*
> <http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=56510>*
> and its predecessor TRAC. The effectiveness of ISO 14721 must be judged by
> the effectiveness of its concepts and terminology in describing concrete
> archival systems, and audits under TRAC and ISO 16363 provide a valuable
> opportunity to do so. *
> *COMMENT: The effectiveness of ISO 14721 is not best judged by how
> precisely it is able to describe any particular archival implementation,
> but much more on how widely it has been adopted to facilitate comparisons
> of archival implementations and issues.  A reference model able to describe
> all implementations in detail would be huge, extremely complex, and
> effectively useless.*
> *In July 2014 the **CLOCKSS Archive* <http://www.clockss.org>* was **certified
> by CRL*
> <http://www.crl.edu/archiving-preservation/digital-archives/certification-and-assessment-digital-repositories/clockss-report>*
> after a rigorous audit against the TRAC criteria, the process for
> certification under ISO 16363 not then being available. CLOCKSS gained an
> overall score that equalled the previous best, and the first ever perfect
> score in the "Technologies, Technical Infrastructure, Security" category.
> All non-confidential documents submitted to the auditors are available *
> *here* <http://documents.clockss.org>*. Four blog posts describe **the
> certification*
> <http://blog.dshr.org/2014/07/trac-certification-of-clockss-archive.html>*,
> **the audit process*
> <http://blog.dshr.org/2014/08/trac-audit-process.html>*, **the lessons
> learned* <http://blog.dshr.org/2014/08/trac-audit-lessons.html>*, and **how
> to run the demonstrations*
> <http://blog.dshr.org/2014/08/trac-audit-do-it-yourself-demos.html>* we
> showed the auditors. *
> *In general, basing the description of the CLOCKSS Archive on the ISO
> 16363 criteria, and thus on the concepts and terminology of ISO 14721
> worked well. Documents describing in detail the way significant OAIS
> concepts apply to the CLOCKSS Archive are available **here*
> <http://documents.clockss.org/index.php/Main_Page#OAIS_Conformance_Documents>*.
> But the **"lessons learned"*
> <http://blog.dshr.org/2014/08/trac-audit-lessons.html>* blog post
> includes a section OAIS vs. CLOCKSS, reproduced here: *
> *Writing the OAIS Conformance Documents made the mis-match between the
> theory of the OAIS reference model and the practice of digital preservation
> in the Web era, and in particular that of the CLOCKSS Archive, evident. The
> conceptual mis-matches between the OAIS Reference Architecture, upon which
> ISO 16363 is firmly based, and the CLOCKSS Archive's architecture fall into
> four broad areas: *
> ·       *CLOCKSS is a dark archive**. Eventual readers of the archive's
> content are unknown, and have no influence over when, whether and how
> content is released from the archive. The OAIS concept of Designated
> Community is thus difficult to apply.*
>    - *COMMENT: This is a misunderstanding of the definition of Designated
>          Community. The Designated Community is defined (see page 1-11) by the
>          archive. The archive does not have to see into the future – they just have
>          to make it clear what they are doing. For example, are the CLOCKSS holdings
>          to be directly understandable to those who only understand Japanese? There
>          must be some criteria being employed, if only implicitly, and this should
>          be documented as the Designated Community – however narrow or broad it may
>          be. *
> *The “eventual users” may or may not be part of that Designated Community,
> and are not required to have any influence on when, whether and how content
> is released. The archive will have some process for making these decisions
> but OAIS does not cover those.*
> ·       *CLOCKSS ingests streams of content**. Content ingested by
> crawling the Web, as much of the CLOCKSS Archive's content is, is not
> pushed from the content submitter to the archive but pulled by the archive
> from the publisher. The publishers of academic journals emit a continual
> stream of content; any division into units is imposed by the archive, not
> by the publisher. The OAIS concept of Submission Information Package, (SIP)
> and the relationship it envisages between the submitter and the archive, is
> difficult to apply. The concept of Archival Information Package (AIP) also
> has some detailed mis-matches, since to collect a stream an AIP must be
> created before it contains any content, and subsequently accumulate content
> over time instead of, as OAIS envisages, being wrapped around a
> pre-existing collection of content at creation time.*
>    - *COMMENT: The AIP is certainly defined by the archive. The SIP is a
>          general concept and the Producer is a role rather than a specific person or
>          organisation (see page 1-14). Someone or something is collecting the
>          content and submitting it to the archive. That person or system is playing
>          the role of the Producer. An individual actor can play multiple roles.*
> *The AIP is not assumed to be created before there is any content. One
> could talk about an AIP container or structure that is prepared before any
> streaming is started.  Until it has all the required components it is not a
> valid AIP.  The archive decides how to create the AIP. OAIS specifies the
> kinds of information which must be logically contained in it.*
> ·       *CLOCKSS has a centralized organization but a distributed
> implementation**. Efforts are under way to reconcile the completely
> centralized OAIS model with the **reality of distributed digital
> preservation*
> <http://purl.pt/24107/1/iPres2013_PDF/Creating%20a%20Framework%20for%20Applying%20OAIS%20to%20Distributed%20Digital%20Preservation.pdf>*,
> as for example in collaborations such as the **MetaArchive*
> <http://www.metaarchive.org/>* and between the **Royal and University
> Library in Copenhagen* <http://www.kb.dk/en/>* and the **library of the
> University of Aarhus* <http://library.au.dk/en/>*. Although the
> organization of the CLOCKSS Archive is centralized, serious digital
> archives like CLOCKSS require a distributed implementation, if only to
> achieve geographic redundancy. The OAIS model fails to deal with
> distribution even at the implementation level, let alone at the
> organizational level*.
>    - *COMMENT: OAIS is a Reference model – not an implementation model
>          (see page 1-2). There is nothing in the OAIS Reference model that would
>          preclude a distributed implementation of an OAIS (see pages 2-2, 4-3, 6-1
>          and 6-3). *
> *The Functional Model is a logical representation, not a design for a
> centralised archive. OAIS does not specify how the various Functional
> Entities are implemented or distributed. Standards for various aspects of
> implementations would be better placed in a separate standard which follows
> the OAIS Reference Model concepts and terminology.*
> *Note for example that NASA’s Planetary Data System (PDS) has been in
> existence for many years and is a large distributed archive.   PDS staff
> had no difficulty applying OAIS to the PDS. *
> ·       *The CLOCKSS Archive contracts-out its operations**. The CLOCKSS
> Archive not-for-profit achieves its low cost of operations by contracting
> them all out under two contracts with Stanford University. This enables
> many costs to be shared with the other users of the LOCKSS technology, to
> the benefit of both. The OAIS model fails to deal with organizational
> divisions such as this.*
>    - *COMMENT: Again the Functional Model does not specify how the
>          Functional Entities are implemented (see page 4-3).*
> *Another mis-match between OAIS and web archiving would have been a
> problem had CLOCKSS not been a dark archive. Access to archived Web
> content, via **Memento (RFC7089)* <http://www.mementoweb.org/>*, direct
> link or text search, occurs at the level of an individual URL. The OAIS
> concept of Dissemination Information Package is difficult to apply to
> access of this kind; it says: *
> *In response to a request, the OAIS provides all or a part of an AIP to a
> Consumer in the form of a Dissemination Information Package (DIP). The DIP
> may also include collections of AIPs, and it may or may not have complete
> PDI. The Packaging Information will necessarily be present in some form so
> that the Consumer can clearly distinguish the information that was
> requested. Depending on the dissemination media and Consumer requirements,
> the Packaging Information may take various forms. *
> *Although there is obviously a lot of room for interpretation here, it
> does not appear to cover the case where the Consumer requests, and the
> archive delivers, a digital object (the headers and body of a URL) in
> exactly the form it was ingested with no Packaging Information. This is
> what Consumers of archived Web content want. It is true that, for example,
> Memento adds header information to its response, but that information
> serves to point to other archived digital objects, potentially in other
> archives, so it can't be considered Packaging Information for the requested
> DIP. Fortunately for us, the trigger process of the CLOCKSS Archive does
> deliver a package containing many URLs, so it more closely matches the OAIS
> DIP concept. *
> *COMMENT: The DIP is a general concept and OAIS does not say how any
> particular DIP is constructed or what it will contain. If/when required, an
> archive must be able to provide the details of how the information in the
> DIP links back to the original information which the archive ingested. Not
> all DIPs need to contain that provenance. Packaging Information is defined
> as: **The information that is used to bind and identify the components of
> an Information Package**. If the response (the DIP) is sent using HTTP
> then the fact that it is HTTP is part of the Packaging Information –
> normally taken care of by the browser without the knowledge or intervention
> of the human user.*
> *Our experience in the TRAC audit of the CLOCKSS Archive reveals a number
> of areas in which the concepts and terminology of ISO 14721 are inadequate
> to describe a real, functioning system. There are two ways to react to
> this. If you believe that ISO 14721 is not a reference model, but a
> definition of an archival system, your response is to say the CLOCKSS and
> any other system that cannot be described using only ISO 14721 concepts and
> terminology is not an archival system. Whatever it is doing is not
> archiving. Over time, as technology and the requirements of the marketplace
> evolve, the terminology of ISO 14721 will describe fewer and fewer systems,
> so the field of archiving will shrink to encompass only legacy systems. *
> *If, on the other hand, you believe that ISO 14721 is a reference model,
> your response is to say that it needs updating with additional concepts and
> terminology adequate to describe the systems that are doing archiving is
> the sense in which that word is generally used. Our experience has
> identified a number of areas in which updating is needed, and I hope to
> adress them in detail in subsequent posts. I'm sure others have found other
> such areas, and I hope they will address them in posts to this Wiki. Lets
> get to work to ensure that a revised ISO 14721 matches the reality of
> current archival systems. Once that is done, we will need to revise the
> standards based upon it, **ISO 16363*
> <http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=56510>*
> and **ISO 16919*
> <http://www.iso.org/iso/catalogue_detail.htm?csnumber=57950>*. *
> *COMMENT: OAIS does not claim to be a reference manual to design archives.
> It claims to:*
> –               *provides a framework for the understanding and increased
> awareness of archival concepts needed for Long Term digital information
> preservation and access;*
> –               *provides the concepts needed by non-archival
> organizations to be effective participants in the preservation process;*
> –               *provides a framework, including terminology and
> concepts, for describing and comparing architectures and operations of
> existing and future Archives;*
> –               *provides a framework for describing and comparing
> different Long Term Preservation strategies and techniques;*
> –               *provides a basis for comparing the data models of
> digital information preserved by Archives and for discussing how data
> models and the underlying information may change over time;*
> –               *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);*
> –               *expands consensus on the elements and processes for Long
> Term digital information preservation and access, and promotes a larger
> market which vendors can support;*
> –               *guides the identification and production of OAIS-related
> standards.*
> *The last point is particularly relevant here. No one standard can cover
> everything. If it attempted to do so, then it would be too large to read
> and would be out of date very quickly.*
> *OAIS is an abstract standard which identified additional standards which
> need to be developed. ISO16363 is an example of such an additional standard
> and there are others which have been created or which are under
> development. Other examples include the XFDU (ISO 13527:2010) standard
> which describes one specific implementation of OAIS packages while the PAIS
> (ISO 20104:2015) describes one possible implementation of the
> Producer-Archive Interface.*
> *Surely the fundamental question when proposing revisions to OAIS is
> whether the core, abstract, concepts need to be updated/corrected, or
> whether additional standards are needed – or perhaps both. The OAIS
> terminology and core, abstract, concepts are logically consistent and
> widely applicable.  *
> *Taking distributed archives as an example, which are mentioned in the
> original post as being beyond OAIS. We noted above that mapping PDS to OAIS
> indicates that this is not true and the core concepts of OAIS do apply. It
> may be sensible to create new standards for the implementation of
> distributed archives, for example to define new ways to implement
> federations or special storage systems. This would not in itself imply
> changes to OAIS, ISO 16363, or ISO 16919.*
> *As noted at the start, OAIS is scheduled for review/revision in 2017. It
> will be important to collect ideas/comments/corrections but it is essential
> to distinguish between changes in OAIS itself versus suggestions for new,
> separate, standards.  Our comments indicate that the points made in the
> original post fall in the latter category. However, if there are other new
> considerations, or if you feel we didn’t understand your post, we would be
> happy to discuss this.  *
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