Information Technology Reference
In-Depth Information
invoked, a new AIP with adequate representation information is created; the new
AIP is a new version of the original AIP containing the transformed content data
and its provenance documents that it was created via transformation.
7.
Authenticity management:
supporting authenticity protocols composed of
steps, as defined in the CASPAR authenticity model (see
Chap. 13
and [
195
]).
PDS documents internal AIP changes that impact authenticity (e.g., format trans-
formations) in the PDI section of the AIP. PDS performs some of this work
automatically while allowing external authenticity management by providing
APIs to manipulate the PDI. PDS provides a secure environment in terms of
maintaining the authenticity (i.e., the identity and integrity) of the data objects
and aims to preserve the relations of a data object to its environment.
8.
Preservation policies:
AIP preservation policies may be added on ingest or
manipulated later on. These policies can be used for example to state the selected
fixity algorithms, and more.
9.
Support preservation-aware placement of AIPs:
organizing the AIPs into self-
describing self-contained clusters according to different parameters to optimize
co-location of AIP sections and related AIPs. Theses clusters may be moved to
secondary storage.
17.6.2.3 PDS Continuous Functionality over Time
A preservation system aimed at preserving data for the long term must first of all be
able to preserve itself, that is, remain functioning and relevant throughout its entire
life span. PDS employs the following means to keep itself up-to-date:
1.
Loading new software modules:
the storlet mechanism facilitates the addition
and update of fixity algorithms and transformations.
2.
Flexible data structures:
as technology and knowledge changes, new structures
may be used for “metadata” such as PDI records. PDS enables to use different
inner structures (accompanied by their relevant RepInfo) to reside in a uniform
record set in a transparent manner.
3. A
layered architecture based on open standards
enables simple replace-
ment and reimplementation of layers according to changes in the system
environment.
4.
Well-defined abstract interfaces
enable simple replacement of implementa-
tion and easy addition of third-party modules (e.g., packaging-format handlers,
“metadata” extractors), according to developments in the technology.
17.6.3 Integration with Existing Archives
In many cases, the data subject to long-term digital preservation already resides in
existing archives. The enterprises recognize the need to have preservation function-
alities in their systems, but are not willing to switch their entire archival system
for that. Reasons may include compatibility with other systems, satisfaction with
