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In response to Charles Cofone's message earlier this week regarding the
EAD DTD and its associated files, I'm appending below the chunk from the
"EAD v1.0 Application Guidelines" (forthcoming from SAA this summer) that
deals with the DTD. This won't address Charles' specific question about
Panorama, but it may help in figuring out the role of the various files
associated with the DTD.

Bill [log in to unmask]
Manuscripts Librarian                |                   The UCI Libraries
Department of Special Collections    |            University of California
949 824.3113                         |                      P.O. Box 19557
949 824.2472 FAX                     |              Irvine, CA  92623-9557

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4.3.  Technical Issues in Authoring

This section provides discussions of the following technical issues as
they relate to the authoring of EAD documents:

 The structure of the EAD DTD and its associated files
 EAD as both an SGML and an XML DTD
 Parsing EAD instances to verify conformance with the DTD
 Data interchange between MARC records and EAD finding aids
 Effects of encoding features on output

4.3.1.  Structure of the EAD DTD

The EAD Document Type Definition (DTD) is an essential component of the
authoring process.  As a document, the DTD is constructed according to a
strict syntax specified by the SGML standard.  For file management
purposes, components of the DTD have been divided in a modular fashion
into the ead.dtd file and four other associated files that function
together as a unit.  Two of these (see below) are not required if the
finding aid is encoded using EAD in XML mode. All five files are simple
text documents in ASCII format that can be viewed and edited in text or
word processing software.  The five files are:

 ead.dtd
 eadbase.ent
 eadnotat.ent
 eadchars.ent
 eadsgml.dcl

ead.dtd: This is the core EAD Document Type Definition file.  It is brief,
containing a version history of the DTD plus entity references that invoke
the other files in the EAD suite.  It also contains three conditional
sections that enable or disable the following features:  XML
compatibility, XLink functionality and the specialized features of EAD's
array of tabular elements.  The use of these features is described in
Sections 4.3.2.1 (XML compatibility), 4.3.5.4 (tabular layout), and 7.2.4
(XLink functionality).

eadbase.ent: This is the largest file of the group and contains the SGML
rules for EAD.

eadnotat.ent: This file contains references to the various types of
notational (non-text) files that might be used within an EAD document.
These include common image file formats such as GIF, JPEG, TIFF, and MPEG
(see Section 6.5.2.4.2 for more information on notational files).

eadchars.ent: This file contains references to the various character sets
that might be used in an EAD document.  All character sets are referenced
by their standard ISO identifiers.  This file is not required if the
document is created in XML, which uses the Unicode character set (or some
subset thereof) by default (see Section 6.5.2.1 for more information on
character sets).

eadsgml.dcl: This is the SGML declaration file, which specifies various
features of the DTD that a processing application may need to know.  While
many DTDs utilize a standard SGML reference declaration, EAD employs its
own version.  Some software applications incorporate the text of the
declaration at the beginning of each SGML instance.  All XML documents,
however, employ a default declaration and so do not require the use of
this file.

4.3.2.  SGML versus XML

EAD is written so that it can be made to conform to the specifications of
either SGML or XML.  The form of the DTD and its associated files that is
available from the EAD home page at the Library of Congress is SGML
compliant.  While XML may, in general, be thought of as a subset of SGML,
there are five differences in XML that must be accommodated to make an EAD
document XML-compliant.  You must be particularly aware of these
differences when converting existing SGML versions of documents into XML.

4.3.2.1  Changes in the DTD Files

If the DTD is to be used with XML applications such as validating
processors, one change must first be made to the "ead.dtd" file.  There is
a section towards the end of the file headed "SGML EADNOTAT AND EADCHARS
INCLUSION/EXCLUSION."  At the end of this section, there is an entity
reference that reads "<!ENTITY % sgml  'INCLUDE'  >".  To "switch off"
SGML compatibility and "switch on" XML compatibility, change 'INCLUDE' to
'IGNORE'.

When you make this change, observe that the explanatory note in this
section of the DTD file points out that "for XML, the eadnotat.ent file
should be invoked in the declaration subset of [the] individual instance."
This means that the file "eadnotat.ent" must be explicitly declared as an
entity in the prolog of each EAD instance that contains links to
notational (non-textual) data such as graphics files (see Section 6.2.3
for a general discussion of the document prolog).  For XML instances, the
prolog of EAD-encoded finding aids should therefore read:

<!DOCTYPE ead PUBLIC "-//Society of American Archivists//DTD ead.dtd
(Encoded Archival Description (EAD) Version 1.0)//EN" "ead.dtd"
[
<!ENTITY % eadnotat PUBLIC "-//Society of American Archivists//DTD
eadnotat.ent (Encoded Archival Description (EAD) Notation Declarations
Version 1.0)//EN" "eadnotat.ent">
%eadnotat;
]>

While it is not necessary to declare the notation file "eadnotat.ent" if
the finding aid does not contain a link to notational data such as
graphics files, it is probably simplest to add it in all cases as a
default.  Note that the Uniform Resource Identifiers (URIs), in this case
simple file names that refer to the "ead.dtd" and the "eadnotat.ent"
files, must point to the exact physical location of these two files on
your system.  Their content may therefore vary from the above examples in
accordance with your local storage practices for the DTD and its
associated files.