The Harvard University Library Digital Finding Aids Project recently
discussed the proposed <container> tag and its relationship to <unitloc> and
<unitid> tags. The more we discussed it, the less clear the distinction
between the two existing tags seemed to be.
The <unitid> is defined in the EAD tag library (Oct. 8, 1996) as "any
identification number that serves as a reference point or control number for
the material that is being described.... The <unitid> element identifies
one or more reference or control numbers ... which may or may not relate to
the physical location of the material."
The <unitloc> tag is defined as "the physical or logical location of the
materials being described."
Because the definitions both admit physical and logical locations, a
clarification on the appropriate use of the tags should be made before
adding yet another, very similar, one. Adding to the confusion is the
statement in the Tag Library that both tags can be used for "shelf
Our reason for being concerned about this is that we foresee difficulties
in application of the EAD because in many repositories, the box and folder
numbers serve as both <unitloc>s (physical or logical location) and
<unitid>s (identification number for the unit) simultaneously.
Looking at the Berkeley guidelines, the templates and examples seem to
uniformly use <unitloc> for box and folder numbers in the container
listing; there are no <unitid>s. We here, on the other hand, have been
using <unitid> for box and folder numbers, our thinking based on the fact
that if it was what the reader needed to put down on a call slip to have
the stuff delivered to her desk, then it was properly a <unitid>,
reserving using <unitloc> solely for unusual physical locations such as
"oversize cases" or "folio shelving" etc.
This is complicated by the fact that there are different numbering systems
being used at different Harvard repositories. Houghton doesn't use boxes
and folders for reference, instead sequentially numbering "items" (i.e.
intellectual units) within a collection; a clear case of a <unitid>,
<unitloc> being reserved for a separate physical location; if, for example,
a particular item is oversized and shelves separately.
We're just not sure how to clearly distinguish the use of these two tags.
If a box and folder number serves as the "ID of the unit", should it be a
<unitid>; or does the fact that it is labelled "box" and "folder" give
greater weight to its physical nature rather than its
The draft SAA Application Guidelines give examples both ways, so this is
something that needs clarification before we add yet a third tag. And
something pretty fundamental to container listings that should be
clarified before there are too many more finding aids out there.
Harvard Digital Finding Aids Project
Leslie A. Morris
Curator of Manuscripts in the Harvard College Library
Houghton Library, Harvard University
Cambridge, MA 02138
e-mail: [log in to unmask]