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For the technically challenged, can someone explain what this means
(EDAC?)  and what the implications of it are for the METS checksum
attribute?

--Robin


On Fri, 15 Mar 2002, Marshall, Neil wrote:

> Carl,
>
> In my opinion, checksums at the essence file level should be a secondary
> tool for file integrity in a digital repository.  I believe the primary tool
> for file integrity should be some form of EDAC applied to the AIP or its
> components.  Checksums tell you something is broke but they can't fix it.
> EDAC such as Reed-Solomon not only tells you when something is amiss but can
> also fix single bit and burst errors as well.
>
> Have a great weekend,
> Neil
>
> -----Original Message-----
> From: Carl Fleischhauer [mailto:[log in to unmask]]
> Sent: Friday, March 15, 2002 8:38 AM
> To: [log in to unmask]
> Subject: Re: [METS] Checksum
>
>
> Thanks for the dialog, MacKenzie.  In our theorizing here at LC, we have
> wished for a file integrity monitoring tool, and pictured a system that
> checks and rechecks a file/object over time.  We seek reassurance about
> the integrity of our objects over the long haul.
>
> Now: how does that relate to METS?  Ummm.  If METS was the metadata for an
> OAIS AIP, then there might be an argument that the "original" checksum (or
> equivalent) is parked there, with the object.  The job of the monitoring
> system would be to run comparisons and alert the owner when a change is
> noticed.  In addition, you would probably want the system to keep a log of
> when the comparisons were made.  Now, in such a system, is it useful or
> needful to know the date when the original checksum (or equivalent) was
> created?  I'd be curious to hear your thoughts.
>
> Carl Fleischhauer
> Library of Congress
>
> On Thu, 14 Mar 2002, MacKenzie Smith wrote:
>
> > In the better late than never category, I've tried to think of any
> problems
> > with this
> > proposal and can't, except the general caveat that it *is* possible to
> take
> > generalization to an absurd extreme, however in this case it makes sense
> to me
> > to go for a general solution over a specific one since I agree that there
> > will be
> > other checksum algorithms and we shouldn't make invalid presumptions.
> >
> > Could we, pehaps, have an optional attribute of checksumtype, and if that
> > attribute is missing, but there is a checksum, assume it's an MD5?
> >
> > And what on earth would the benefit of a checksum create date be?
> >
> > MacKenzie/
> >
> > At 09:57 AM 3/5/2002 -0500, Robin Wendler wrote:
> > >One of the general questions that came out of the recent
> > >(and soon to be documented, I swear) meeting on technical metadata for
> > >audio was about the METS <checksum> attribute of the <file> element.
> > >Right now, this is defined explicitly as MD5, but there are now and
> > >undoubtedly will continue to be other checksum algorithms in use. We were
> > >wondering whether it would be better/possible to generalize this in METS,
> > >providing for the checksum type, value, and create date. It seems better
> > >to raise this now, rather before we hit the big Version 1.0.
> > >
> > >What do others think about this?
> > >
> > >-- Robin
> > >
> > >Robin Wendler  ........................     work  (617) 495-3724
> > >Office for Information Systems  .......     fax   (617) 495-0491
> > >Harvard University Library  ...........     [log in to unmask]
> > >Cambridge, MA, USA 02138  .............
> >
> > MacKenzie Smith
> > Associate Director for Technology
> > MIT Libraries
> > Building 14S-208
> > 77 Massachusetts Avenue
> > Cambridge, MA  02139
> > (617)253-8184
> > [log in to unmask]
> >
>

--
Robin Wendler  ........................     work  (617) 495-3724
Office for Information Systems  .......     fax   (617) 495-0491
Harvard University Library  ...........     [log in to unmask]
Cambridge, MA, USA 02138  .............