[Koha] MARC tag for noting Koha auto-modification?

[MJ Ray]

A little introduction before the question: I'm working on making Koha
recover a little from an incomplete marcxml record.  This should
reduce the number of times that Koha fails (with a code 500 Internal
Server Error) or returns a misleading 404 Not Found to a search or
link, usually because a MARC record was imported with incorrect settings.
Currently we have to intervene directly in the database to repair such
problems and that's no fun.  This is a symptom of
http://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=2916
that I mentioned in another thread yesterday.

My solution is to make Koha try to recover by regenerating marcxml
from the binary MARC record.

This would be harmful for mature records, but you can't get very far
with an incomplete MARCXML record anyway, so this doesn't usually
happen to mature records.  It usually happens when someone has managed
to be imported or entered with inconsistent character encodings or
other corruption.  Regeneration should be just enough to allow opening
the record editor or using the Koha C4 API to fix whatever's broken.

Further discussion:
http://stats.workbuffer.org/irclog/koha/2010-11-25#i_550339
http://stats.workbuffer.org/irclog/koha/2010-12-08#i_559023

I've been advised to dump the broken MARCXML record to system logs
and note in the regenerated record when it was done.

So, the question is this: Where should the regeneration note go?
jcamins suggested tag 993 because it's used for such things by the ANS.
Would that be OK with everyone?

Thanks,
-- 
MJ Ray (slef), member of www.software.coop, a for-more-than-profit co-op.
Past Koha Release Manager (2.0), LMS programmer, statistician, webmaster.
In My Opinion Only: see http://mjr.towers.org.uk/email.html
Available for hire for Koha work http://www.software.coop/products/koha