From: Priscilla Caplan
> Also, I'm told someone at LC is looking at Saasha's comment about the
> schema.

When discussing the role of edtf in the premis schema it is helpful to first
review the background.  The premis 2.0 schema dates back to July 2008 -
three years ago. At that time the edtf initiative was barely begun. And in
fact edtf was initiated to address premis requirements.  So the initial (and
very preliminary and primitive) draft of edtf was solely (or nearly solely)
aimed at premis requirements and it was that initial draft that got coded
(somewhat crudely) into a number of regular expressions in the premis 2.0
schema. 

Since then edtf has taken on a life of its own with a constituency many of
whom have no connection to premis.   There was never any intention to keep
premis synchronized with the edtf drafts for obvious reasons: edtf was a
moving target when premis 2.0 was released; and when 2.1 was released,
relatively recently (January 2011), edtf had become far more complex than it
had been originally, in fact far too complex to render it into a set of
regular expressions. So the decision was to leave the edtf representation in
2.1 exactly as it had been in 2.0 because there was no real reason to change
it, but there was no implication intended that it conformed to any specific
draft of edtf other than the original preliminary draft.  

There is no reason to now tinker around with the regular expressions in the
premis schema, unless someone feels that they do not support requirements,
but certainly not for purposes of conformance to edtf. Instead, I suggest
waiting until edtf is stable (and it is fast approaching equilibrium as we
speak) and then evaluate how to represent it in the next version of the
premis schema. 

--Ray