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Re: comments regarding versioning

From: Herbert Van de Sompel <hvdsomp@gmail.com>
Date: Tue, 30 Jun 2015 10:50:08 -0600
Message-ID: <CAOywMHc=HgSJrOVY-3u337-6NMb47RvF4yBGXJOom=CY2FCamw@mail.gmail.com>
To: Erik Wilde <dret@berkeley.edu>
Cc: "public-dwbp-wg@w3.org" <public-dwbp-wg@w3.org>, Herbert Van de Sompel <hvdsomp@gmail.com>
On Mon, Jun 29, 2015 at 11:20 AM, Erik Wilde <dret@berkeley.edu> wrote:
> hello herbert.
>
> thanks for your reponse!
>
>> I agree they are very similar, and I actually made a comment that the
>> Memento pattern for datetime-based versioning [1] can be used in both
>> cases.
>
>
> if you think they're similar but not actually the same, what would you say
> the difference is? i am still struggling to see it, and if they do remain
> separate, it might be helpful to better explain how they are different.
>

Well, the difference is in the nature of the content, by which I mean
that I have a hard time thinking about a vocabulary as a dataset. But
other than that, when it comes to versioning, both datasets and
vocabularies are just resources that can be versioned, and to which
Memento patterns for version disclosure and version access can be
uniformly applied.

Overall, I think I should be happy with the fact that Memento is being
mentioned with regard to versioning. On the other hand, I am not sure
why alternatives such as:
- the use of an "API for version access" mentioned Best Practice 8
- the use of an "API for access to version history" mentioned in Best Practice 9
should be promoted, understanding that there is an RFC (7089) (which
was 4 years in the making) that provides - IMO - all the required
capabilities and is fully aligned with REST, follow-your-nose. I guess
this question is related to what the ultimate goal of this document
is.

For example, the versioning problem shown in Figure 2 can be fully
addressed by means of the patterns described in RFC7089 and in
http://mementoweb.org/guide/howto/ . The one thing not explicitly
addressed in http://mementoweb.org/guide/howto/ is the notion of
Distributions, ie various serializations of a same dataset version.
But this is readily addressed by:
- Adding MIME type information in TimeMaps and Link headers using the
"type" attribute
- Using both datetime and content negotiation with a TimeGate (which
we support in the DBpedia archive) as per this excerpt of RFC7089:

"When negotiating in the datetime dimension, the regular content
negotiation dimensions (media type, character encoding, language, and
compression) remain available. It is the TimeGate server's
responsibility to honor (or not) such content negotiation, and in
doing so it MUST always first select a Memento that meets the user
agent's datetime preference, and then consider honoring regular
content negotiation for it."

Maybe Memento is not understood well enough yet. So, maybe it is not
clear to many how it addresses all these versioning requirements. I
would be most happy to provide additional information, if that would
be considered helpful.

Greetings

Herbert

> on a different note: is there an open issue tracker for the drafts? i sent
> some more comments by email, but i am not sure that's the best way to get
> the captured and responded to.
>
> thanks a lot and cheers,
>
>
> erik wilde | mailto:dret@berkeley.edu  -  tel:+1-510-2061079 |
>            | UC Berkeley  -  School of Information (ISchool) |
>            | http://dret.net/netdret http://twitter.com/dret |



-- 
Herbert Van de Sompel
Digital Library Research & Prototyping
Los Alamos National Laboratory, Research Library
http://public.lanl.gov/herbertv/

==
Received on Tuesday, 30 June 2015 16:50:47 UTC

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