The OAIS diagram (above)
shows the relationships among the functions. It looks a lot like
a system architecture diagram, so many people understand it as
such. But it is not. The rounded rectangles identify groups
of related functions, not components in an implementation. In the
real world, the functions do not have to reside on the same server
or within the same organization. The groups can be broken apart
and their functions can be distributed in many configurations.
The story of "O":
A Digital Object in an
OAIS-compliant System
Information packages have different names at different stages in
the archival process, representing the nature of the object at that
point in the process.
A digital object comes into the system as a Submission Information
Package (SIP), consisting of the object and a required set of
metadata. The Producer is responsible for passing the SIP off
to Management.
The SIP goes through the Ingest functions where it is processed
and accepted into the system in accordance with accepted practice
and rules and becomes an Archival Information Package (AIP).
The AIP then contains the content of the SIP plus any additional
metadata the system requires in the way of preservation elements.
From that point on, metadata is added to the AIP for every action
that affects the object.
In addition to ingesting the SIPs into the system, Management
is responsible for being able to steward the AIPs over time and
enable the delivery of AIPs to the Consumer as Dissemination Information
Packages (DIP).
Most systems require the successful implementation
of several functions—Administration, Data Management,
and Common Services (which are not represented in the model)—to
operate smoothly. An OAIS adds two key functions: Archival Storage
and Preservation Planning, which identify and apply appropriate
preservation strategies to move the AIPs into the future in
a way that maintains them as readable, usable, and understandable
objects.
The Consumer appears at the end of the model and may appear to
simply request and receive DIPs. Understanding the interests,
needs, and priorities of the Consumer as reflected by the kinds
of queries submitted and the kinds of DIPs expected—both
of which are likely to change over time—may have significant
implications for the range of digital objects that are ingested.
It may also be the basis for a truly successful OAIS, one
that performs the preservation functions well and is actively
used by target consumers.
