4.4 AIP Preservation #
4.4.1 - The repository shall have specifications for how the AIPs are stored down to the bit level. #
Response #
SP’s AIPs consist of two main components, the Content Object and preservation metadata. The preservation metadata contains descriptive and structural metadata about the object, as described in the Metadata Specifications. In addition, the preservation metadata contains format information such that the object is interpretable down to the bit-level, as described in 4.2.5.
These components are packaged together within the preservation metadata using relationship and event links.
Responsibility #
- Digital Preservation Librarian
Documents #
4.4.1.1 - The repository shall preserve the Content Information of AIPs. #
Response #
The Content Information component of the SP AIP is preserved according to the Preservation Strategic Plan and Preservation Implementation Plan. The Content Information is preserved, along with information documenting any transformations or actions taken on the AIP. The original, Provider-supplied Content Information is never deleted and the preservation metadata will always contain a reference to its location within the repository.
Responsibility #
- Digital Preservation Librarian
Documents #
- Workflow Charts
- Preservation Strategic Plan
- Preservation Implementation Plan
- Metadata Specifications
4.4.1.2 - The repository shall actively monitor the integrity of AIPs. #
Response #
SP is committed to maintaining the integrity of objects in its care. This includes regular fixity checking of all accepted and ingested files.
- At the time of ingest, three checksum values are calculated for each file: MD5, SHA-1, and CRC32. These values are stored in the preservation metadata for each object.
- Nightly, a set number of files in the repository will have their current checksum calculated (using a single checksum) and compared to this stored value, which is expected to match. In cases where the calculated and stored values do not match, this is reported to Scholars Portal’s issue tracking system, JIRA.
PREMIS events are created in the preservation metadata at the object-level for the fixity checks and success or failure of these checks are logged.
Please see Fixity Check Procedures for more details.
The Content Information is stored on disk, and the fixity information is stored in the TDR database.
Responsibility #
- Digital Preservation Librarian
Documents #
4.4.2 - The repository shall have contemporaneous records of actions and administration processes that are relevant to storage and preservation of the AIPs. #
Response #
SP automatically captures events that occur throughout the object’s life within the repository. The repository uses PREMIS event vocabulary to record ingest, file replacement or reload, and transformation of the file in the preservation metadata of each AIP. The preservation metadata also records the storage location of each file comprising the AIP.
Responsibility #
- Digital Preservation Librarian
Documents #
4.4.2.1 - The repository shall have procedures for all actions taken on AIPs. #
Response #
SP has consistent procedures for allowable actions taken upon its AIPs, as specified in the Preservation Implementation Plan. SP AIPs can be replaced or reloaded at the request of the Provider, and their identifiers adjusted accordingly. AIPs are not deleted as a part of normal operations. Please see the TDR Script Diagram for detailed documentation of procedures occurring during ingest, as well as the URI & File Naming Plan for a description identifier adjustment.
If there are any problems during these procedures, an error message is sent to the loaders.
Responsibility #
- Digital Preservation Librarian
Documents #
4.4.2.2 - The repository shall be able to demonstrate that any actions taken on AIPs were compliant with the specification of those actions. #
Response #
In the repository, all actions taken on AIPs are done programmatically. This ensures that actions are consistent and compliant with specifications. Any deviation that the program encounters appears as an error and is recorded and reported to the loaders.
Responsibility #
- Digital Preservation Librarian