[IGS-DCWG-16] Re: [IGS-DCWG-15] Re: [IGS-DCWG-14] Re: Resupplied data

[Carey Noll]

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IGS-DCWG Mail      02 Jul 13:25:40 PDT 2003      Message Number 16
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Author:  Carey Noll/CDDIS

Dear Colleagues,

   Sorry it took me so long to get back to this discussion on resupplied
data.  I am glad to have seen so many emails about the topic; I think 
the discussion has been quite valuable.  I will try to summarize the
messages and see where to go next.

o  We all agreed that data resupplies need to be obviously known and
communicated to other data centers (DCs) and analysis centers (ACs).

o  Some approaches:

   1.  Check filesizes on incoming files; if different repost
   2.  Check GSAC dhf files and if checksums differ, repost
   3.  Maintain delivery history file and scan for incoming files; if
       checksums differ, repost
Should the data replacement process be automated or should the replacement
only take place upon notification by the supplier?  

o  Communications.  It seems that we must communicate and keep track of
replacement data.  A standardized email has been suggested.  This email
could be sent to all data centers and ACs.  I also think maintaining an
on-line history file of replacements would be valuable. We could set up a
distribution list (not sure if we want a majordomo type system which archives
the emails) of DC and AC contacts. The text history file would be accessible
through the web and ftp and updated based upon the email.

o  How many of the current DCs have implemented the GSAC?  I know SOPAC,
CDDIS, and BKG.   Is it better to use a checksum or a filesize difference
to determine a file has been replaced?

Just some more thoughts on my part.

Carey.

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Ms. Carey Noll  Manager, Crustal Dynamics Data Information System (CDDIS)
                                           Secretary, ILRS Central Bureau
Code 922                                   E-mail:  Carey.E.Noll at nasa.gov
NASA GSFC                                           Voice: (301) 614-6542
Greenbelt, MD 20771                                   Fax: (301) 614-6099
USA                  WWW:  http://cddisa.gsfc.nasa.gov/cddis_welcome.html
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