Information Technology Reference
In-Depth Information
Of these only XFDU has close connections to OAIS and in particular full
support for all types of Representation Information. Therefore we use XFDU in
our examples, but this should not be taken to mean this is the only way.
OAIS describes several package variants, but only the Archival Information
Package (AIP) has mandatory contents and we look in detail at the AIP next.
11.2 Archival Information Packaging
The AIP is a critical element in OAIS. There is a distinction which is made between
an Archival Information Unit (AIU) and an Archival Information Collection (AIC),
both of which are special types of AIPs (Fig.
11.1
).
There is an analogy here with what were termed in
Sect. 4.1
Simple Objects and
Composite Objects.
OAIS defines:
•
Archival Information Collection (AIC):
An Archival Information Package
whose Content Information is an aggregation of other Archival Information
Packages.
•
Archival Information Unit (AIU):
An Archival Information Package where
the archive chooses not to break down the Content Information into other
Archival Information Packages. An AIU can consist of multiple digital objects
(e.g., multiple files).
This shows that an AIC is a Composite Object, and the AIU could in some ways be
described as a Simple Object - although clearly it has components.
For further details of the useful terminology associated with AICs the reader
should consult OAIS.
Fig. 11.1
Specialisations
of AIP
