Information Technology Reference
In-Depth Information
package header
packageHeader
data objects
“metadata” objects
dataObjectSection
metadataSection
xml Id
URI
metadataObject
metadataObject
dataObject
URI
“Metadata”
Category
Pointers
(xml Ids)
xml Id
Category
Class
URI
REP
PDI
DED, SYNTAX, OTHER
informationPackageMap
CONTEXT, PROVENANCE,
REFERENCE, FIXITY, OTHER
behaviorSection
xml Id
ContentUnit
behaviorObject
DMD
OTHER
ANY
DESCRIPTION, OTHER
OTHER
Structure map
URI
xfdu
Fig. 11.3
XFDU manifest logical view
The
informationPackageMap
records information about
content units
, which
are used to associate data in the
dataObjectSection
to “metadata” in the
meta-
dataSection
. The association is done via XML identifiers, and maps to the OAIS
concept of Content Information Object, the combination of a digital object and its
RepInfo.
A diagram of the full XML schema of the XFDU is shown in Fig.
11.4
.This
schema keeps AIPs consistent and standard while allowing a flexible and adaptable
implementation. By extending the XFDU schema to provide domain specific AIPs
it is possible to allow the inclusion of additional information while maintaining
the standardization and consistency that are two of the main advantages of using
XFDU for preservation. ESA has demonstrated this by extending the XFDU schema
into SAFE, which includes spacecraft mission-specific information embedded in the
XFDU manifest.
A toolkit for creating and reading XFDUs is available from the XFDU web site
[
148
] and GAEL XFDU web site [
149
].
11.3.1 XFDU and TDO
Because both embody packaging techniques, the XFDU structure does implement
many, perhaps all, of the concepts of the Trustworthy Digital Object (TDO) [
8
].
However the latter seems to rely on emulation (see
Sect. 7.9
) and in particular the
UVC (see
Sect. 7.9.4.3
) as its ultimate preservation technique.
