Information Technology Reference
In-Depth Information
Chapter 17
The CASPAR Key Components Implementation
This chapter presents the CASPAR Key Components in somewhat greater detail.
Having discussed the various ways of countering the threats to digital preservation,
and distinguished the domain dependent from the domain independent, this chapter
presents the CASPAR implementation of these components
.
17.1 Design Considerations
One important consideration is the preservability of the infrastructure components
(Fig.
17.1
) themselves. The approach taken by CASPAR was not to use recur-
sion and say that one would use CASPAR to preserve the components. Instead the
approach was to make the components relatively easy to re-implement. Thus in the
rest of this chapter we provide more details of the components and then give the
interface definitions.
•
These interfaces have been kept relatively simple in order to make them easier to
re-implement.
•
it must be possible to integrate these components into existing repositories
•
we must not demand that all components are available all the time
•
there must not be single points of failure.
17.2 Registry/Repository of Representation Information Details
In terms of access, interpretation and use of the Representation Information, the
key concept here is to try to make the access to, and the form of, the initial piece
of Representation Information as “standard” as possible. In CASPAR this piece
of initial Representation Information is called the “RepInfoLabel” which will be
described later. The purpose of this initial piece of RepInfo is to provide a categori-
sation of the types of RepInfo which are available for the Data Object, using the
classification of RepInfo which OAIS provides (Fig.
17.2
). Such a breakdown gives
