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Re: Approval requested for CIF Core 2.1



	The proposed changes seem OK except that I wonder whether we are
actually allowed to change 'numb' to 'char' (4864, 4936) without also
changing the dataname; what problems are we likely to encounter?  I
suppose there will be no problem since we are broadening the definition. 
A cif writen with a number would still be correctly read using the new
dictionary, but it would not work the other way around.  We cannot
redefine char to numb.

	The splitting up of datanames grouped in the same datablock has
implications for Comcifs if we would like to introduce the new DDL1 item
of sub-categories.  While DDL1 exists independently of Comcifs, Comcifs
does need to decide which features of DDL1 it wishes to use.  I personally
think Brian's proposal is a good one, but I would like to get Comcifs
permission before introducing sub-categories.  Therefore I think splitting
up the grouped datanames should be delayed until the next revision and
until the matter of sub-categories has been discussed and approved by
Comcifs.

			David


*****************************************************
Dr.I.David Brown,  Professor Emeritus
Brockhouse Institute for Materials Research, 
McMaster University, Hamilton, Ontario, Canada
Tel: 1-(905)-525-9140 ext 24710
Fax: 1-(905)-521-2773
idbrown@mcmaster.ca
*****************************************************


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