[Go-essp-tech] versions, checksums and the TDS
Karl Taylor
taylor13 at llnl.gov
Sat Sep 24 10:17:01 MDT 2011
Dear all,
Concerning:
On 9/24/11 4:35 AM, Estanislao Gonzalez wrote:
> 2) checksums
> They are the only reference to the outside that a data node give of the
> changes a file suffered from one version to another, i.e. for
> replication we use that information to retrieve only files that change
> from one version to another. The same principle could be applied for
> tools designed for end users.
without disputing that checksums should be mandatory, I want to point
out that a user who has lost the checksum associated with a file he has
downloaded shouldn't have to recompute the checksum to determine whether
his file is a copy of a file residing at the datanode. Recall that
recorded in each netCDF file is a unique tracking_id, which I'm almost
positive is also in the thredds catalog. It will certainly be quicker
for the user to read the tracking_id and then check whether it matches
the latest version. I think we want to maintain tracking_id as an
option for checking whether new files exist in a new version.
best regards,
Karl
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ucar.edu/pipermail/go-essp-tech/attachments/20110924/d0b42f27/attachment.html
More information about the GO-ESSP-TECH
mailing list