[Moims-dai] [EXTERNAL] Re: Architecture Description

Thu Jun 13 17:09:40 UTC 2019

Hi all,

This is the discussion I remember.  Here is a use case.

In the PDS4 Information Model we have the following hierarchy.

1.       Bundle – A Bundle contains one or more Collections (E.g., a Bundle is typically a package containing a data product collection for a single instrument together with one or more collections of information necessary for using the data. ) The PDS4 bundle is effectively an OAIS Information_Package.

2.       Collection -> A Collection contains one or more Data Products of a single type  (e.g., all the raw images from the Viking Orbiter 1 and 2 cameras)

3.       Data Products -> A Data Product containing data from a scientific observation. (e.g., one raw image from the Viking mission)  The Raw image and its PDS4 label is effectively an OAIS Information_Object.

Viewing PDS4 as an OAIS, if a user finds and requests a Viking Image from the PDS they will typically receive an Information Object, i.e., the raw image (Data Object) and its Representation_Information. If the user then requests the Fixity Information for the raw image, under the OAIS-IF, how should system get the Data_Object’s Fixity_Information?

According to the OAIS-IF Information Model the Fixity_Information is associated with the Preservation_Description_Information and the Preservation_Description_Information is associated with an Information_Package. This suggest that given the Viking Image Information_Object, the system will navigate through the Collection to the Bundle (an Information_Package), get the Preservation_Description_Information, get the  Fixity_Information, and then locate and return the Fixity_Information specific to the Viking Image Information_Object.

Another view is that the system knows that the Viking Image Information_Object is Content_Information and directly gets the associated Fixity_Information.

Thoughts?

Thanks,
Steve

From: MOIMS-DAI <moims-dai-bounces at mailman.ccsds.org> On Behalf Of david
Sent: Wednesday, June 12, 2019 11:59 AM
To: MOIMS-Data Archive Interoperability <moims-dai at mailman.ccsds.org>
Cc: Hughes, John S (398B) <john.s.hughes at jpl.nasa.gov>
Subject: [EXTERNAL] Re: [Moims-dai] Architecture Description

Yes, necessary, but not sufficient.
David

Sent from my Samsung Galaxy smartphone.

-------- Original message --------
From: Mark Conrad <mark.conrad at nara.gov<mailto:mark.conrad at nara.gov>>
Date: 12/06/2019 19:15 (GMT+00:00)
To: MOIMS-Data Archive Interoperability <moims-dai at mailman.ccsds.org<mailto:moims-dai at mailman.ccsds.org>>
Cc: "Hughes, John S (398B)" <john.s.hughes at jpl.nasa.gov<mailto:john.s.hughes at jpl.nasa.gov>>
Subject: Re: [Moims-dai] Architecture Description

"Preservation Description Information (PDI): The information, which along with Representation Information, is necessary for adequate preservation of the Content Data Object"

On Wed, Jun 12, 2019 at 1:38 PM David Giaretta <david at giaretta.org<mailto:david at giaretta.org>> wrote:
In OAIS terms PDI may be part of any Information Package. If the Information Package is an AIP then by implication the Information Object it will probably be Content Information.

..David

From: MOIMS-DAI <moims-dai-bounces at mailman.ccsds.org<mailto:moims-dai-bounces at mailman.ccsds.org>> On Behalf Of Mark Conrad
Sent: 12 June 2019 17:51
To: MOIMS-Data Archive Interoperability <moims-dai at mailman.ccsds.org<mailto:moims-dai at mailman.ccsds.org>>
Cc: Hughes, John S (398B) <john.s.hughes at jpl.nasa.gov<mailto:john.s.hughes at jpl.nasa.gov>>
Subject: Re: [Moims-dai] Architecture Description

" I cannot understand why Content_Information (a sub-type of Information_Object) shows methods get/putPreservationDescriptionInformation.  That would normally indicate that these are additional methods in addition to those which Information_Object has – but why? "

Because PDI does not apply to all Information_Objects - only Content_Information.

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<mailto:mark.conrad at nara.gov>

On Tue, Jun 11, 2019 at 9:17 AM David Giaretta <david at giaretta.org<mailto:david at giaretta.org>> wrote:
Hi Steve

I can understand why get/setDataObject and get/putRepresentationInformation are methods in Information_Object but I don’t understand why get/putInformationObjectMetadata is there. Also don’t understand the difference between get/setPID and get/putIdentificationInformation. Also what is the difference between put and set?

I cannot understand why Content_Information (a sub-type of Information_Object) shows methods get/putPreservationDescriptionInformation.  That would normally indicate that these are additional methods in addition to those which Information_Object has – but why?

Is there are mix-up between Information_Object and Information_Package?

I suspect that part of my confusion arises from using the ontology rather than a UML tool to create the diagrams etc. but that would not explain my questions/comments above.

Regards

..David

From: MOIMS-DAI <moims-dai-bounces at mailman.ccsds.org<mailto:moims-dai-bounces at mailman.ccsds.org>> On Behalf Of Hughes, John S (398B) via MOIMS-DAI
Sent: 11 June 2019 03:16
To: MOIMS-Data Archive Interoperability <moims-dai at mailman.ccsds.org<mailto:moims-dai at mailman.ccsds.org>>
Cc: Hughes, John S (398B) <john.s.hughes at jpl.nasa.gov<mailto:john.s.hughes at jpl.nasa.gov>>
Subject: [Moims-dai] Architecture Description

Hi all,

Attached please find the Model Specification Document (html format) and two diagrams with a few updates to some core classes. In particular the DPI get/put methods have been moved to the Content_Information class as per recent discussions.

Thanks,
Steve

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