Each Node will keep information regarding digital objects held by the Digital Preservation Network in the "Registry". As part of DPN's mandate is to separate implementation from specification, each node will independently create their own set of services to support Registry operations. Each node will implement a registry independently, as such it is only necessary for use to define which fields will be share across the federation of nodes. Registry entries for all objects will be held by all nodes, thus the level of protection for object description is very high.
The registry, conceptually, is an implementation-agnostic way for Nodes in the DPN Federation to keep metadata about DPN objects synchronized. The overall aim of the registry is to keep an easily accessible set of metadata to allow for the effective management of DPN objects across the Federation. Discovery and rich metadata are out of scope for the DPN registry at this time and proper management of objects across the federation is the primary objective of the registry.
The primary means of exchange for registry data between Nodes is via messaging.
Registry Fields
| Name | Value |
|---|---|
| dpn_object_id: | UUID |
| local_id: | Bla-repository-specific |
| first_node_name: | source repository |
| replicating_node_names: | [hathi, chron, sdr] |
| version_number: | number |
| previous_version_object_id: | UUID to previous version |
| forward_version_object_id: | UUID to next version or nil |
| first_version_object_id: | UUID |
| fixity_algorithm: | sha256 |
| fixity_value: | some sha256 value |
| last_fixity_date: | ISO 8601 |
| creation_date: | ISO 8601 |
| last_modified_date: | ISO 8601 |
| bag_size: | number of bytes of the serialized bag |
| brightening_object_id: | [UUID1... UUIDn] |
| rights_object_id: | reference to DPN and repository agreements [UUID1 ... UUIDn] |
| object_type: | "data" "rights" "brightening" |
DPN Versioning