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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Gavin,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">>>
</span>In my opinion OpenDAP (or something similar) is the only way<o:p></o:p></p>
<p class="MsoNormal">><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal">> actually... that may not be impossible.<br>
> (pondering...)<br>
> :-)<br>
<br>
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I would postulate it is near impossible, at least within the constraints of NetCDF3-API compatible OPeNDAP. OPeNDAP is a protocol for accessing a single "dataset",
the netcdf metadata of that dataset is delivered in a single HTTP GET request. Do you want to deliver the metadata for the entire archive in a single request? If you mean "or something similar", yes of course we should be aiming at a system that allows users
to access data seamlessly. That's what we are trying to build, right?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">On Estani's wider point, I think it's not black and white. Many users don't want to bother about files when the file divisions appear arbitrary (e.g. splitting
a field into time chunks) provided the tools are good enough to support more sophisticated access (Sebastien's point). The concept of the DRS atomic dataset is meant to define sensible units of data that the user will understand; remember atomic datasets?
:-)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">However, all users understand the need to divide information into units to make them manageable. Everyone gets used to using files at some level -- PDFs, exel
spreadsheets, source files, etc. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">And there is one specific use case that requires users to be aware of files: verifying data integrity and provenance. A user should be able to check the checksum
of the data they downloaded and verify it was downloaded correctly. If they find a random NetCDF file on their hard drive they should be able to ask ESGF where it came from by looking up the checksum or tracking_id. An interesting future area of research
could an algorithm for hashing virtual NetCDF datasets but we aren't there yet.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">My instinct is that we should accept datasets are collections of files and not try to completely hide this idea, however most of the system should focus on
datasets because they more flexible. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Stephen.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">P.S. This is exactly what I want to cover in the data model interface group so I'm glad there is interest out there.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;color:#1F497D">---<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;color:#1F497D">Stephen Pascoe +44 (0)1235 445980<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;color:#1F497D">Centre of Environmental Data Archival<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;color:#1F497D">STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext"> Gavin M. Bell [mailto:gavin@llnl.gov]
<br>
<b>Sent:</b> 01 June 2011 22:16<br>
<b>To:</b> Estanislao Gonzalez<br>
<b>Cc:</b> Cinquini, Luca (3880); Pascoe, Stephen (STFC,RAL,RALSP); go-essp-tech@ucar.edu; esg-node-dev@lists.llnl.gov<br>
<b>Subject:</b> Re: [Go-essp-tech] [esg-node-dev] Use of <metadata> element in THREDDS catalogs<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">actually... that may not be impossible.<br>
(pondering...)<br>
:-)<br>
<br>
On 6/1/11 9:24 AM, Estanislao Gonzalez wrote: <o:p></o:p></p>
<p class="MsoNormal">In my opinion OpenDAP (or something similar) is the only way to go... it would be great if it could act on an
<b>archive </b>wide aggregation without any performance hit. Maybe some day...<o:p></o:p></p>
<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<pre>-- <o:p></o:p></pre>
<pre>Gavin M. Bell<o:p></o:p></pre>
<pre>Lawrence Livermore National Labs<o:p></o:p></pre>
<pre>--<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre> "Never mistake a clear view for a short distance."<o:p></o:p></pre>
<pre> -Paul Saffo<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>(GPG Key - <a href="http://rainbow.llnl.gov/dist/keys/gavin.asc">http://rainbow.llnl.gov/dist/keys/gavin.asc</a>)<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre> A796 CE39 9C31 68A4 52A7 1F6B 66B7 B250 21D5 6D3E<o:p></o:p></pre>
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