Use of Approved Inventory Systems
This guidance identifies the Library's approved inventory systems for digital collection content and also requires the use of approved inventory systems to establish administrative control for the Library’s permanent digital collections.
The Library of Congress inventories digital content to establish general administrative control over digital collections. These inventory control systems support the creation and management of technical and administrative information about the digital collections, including data integrity monitoring and location tracking. Digital content in the Library’s digital collections must be managed through an approved inventory system.
Digital content not under inventory control in approved inventory systems is not considered to be under the Library's custodial care as part of the Library of Congress' digital collections. Digital content not inventoried in an approved inventory system should not be assumed to be under trustworthy, long-term management. If such uninventoried digital content is considered by a custodial unit to be material that falls in scope of the Library’s general collections, that unit should work with Digital Collection Management and Services to ensure that the content comes under inventory control.
Storing Multiple Copies
Responsible digital stewardship requires the creation and management of multiple copies of digital items to ensure the ability to recover items that are damaged or lost. OCIO provides digital content managers with storage infrastructure that satisfies needs for ensuring enduring access to digital collection content. The current long term storage infrastructure ensures that multiple copies of digital content are created and managed as a routine procedure for all digital collection content entering the Library’s permanent digital collections. Copy creation, storage, and verification are managed by the Library's approved inventory systems. When digital content designated for long-term preservation is brought into the Library’s inventory systems, automated workflows create at least four copies that are stored in at least two independent systems and separate geographic locations.
Digital collections stored for long-term preservation are currently stored in nearline or offline tape storage systems. These provide stable storage for digital content inventoried by the Library. To best support the management of multiple copies of digital content going forward, custodians for digital content management have articulated the following as business needs for future improvements to the Library of Congress storage infrastructure: maintain at least one copy of all content on storage that supports active use and monitoring of data integrity and at least three total copies for replication and recovery if necessary. Multiple copies support replication for potential repair actions and should be stored on various types of storage media. Library Services will be able to request or verify file fixity at scheduled intervals for all independent storage systems, in conformance with Data Integrity Monitoring needs.
Logging Content Changes
Preservation and technical metadata for digital content that has been selected for the Library's permanent digital collections is essential for ensuring enduring access to digital collection content. The Library’s approved inventory systems have been developed to align with the data model for preservation metadata established in the Preservation Metadata: Implementation Standard (PREMIS). By ensuring that actions on digital collection content are effected through the inventory system, these actions are recorded and logged.
The Library’s approved inventory systems are routinely used to add, modify, and remove content from the Library's digital collections. Inventory systems support automated logging as well as manual entry of notes to describe changes. If service units must change or update content outside the inventory system, such changes must be logged in the inventory system to ensure that the Library has an accurate and accountable record of actions that ensure the long-term viability, presentation, and security of digital collections. Digital Content Managers are responsible for ensuring that intentional changes are logged in inventory systems.
Organization of Content in Inventory Systems
The organization of content within storage and inventory systems is a critical aspect of intellectual and administrative control. Since processing decisions, automated content acquisition workflows, and routine collections care affect the ways that content is stored and inventoried, this guidance element summarizes the overarching principles for organizing and preparing content for long-term storage in the Library's digital storage infrastructure. In accordance with guidance on the maintenance of original formats, content is stored and preserved as it was delivered to the Library.
Digital content inventory records must be associated with unique identifiers, appropriate to the type of content, to facilitate linking content to descriptive metadata in other systems. Digital content ingested in BagIt structure should be bagged at the level of collection organization. For example, if a collection is digitized according to boxes, bags may correspond to boxes, or if a collection is imaged on microfilm, bags may correspond to individual reels of film.
Naming Conventions within Inventory Management Systems
This guidance facilitates the standardization of naming practices within inventory systems. The following conventions describe the general guidelines for naming content in inventory systems:
- Naming conventions should be consistent within projects, and are generally consistent across projects within divisions.
- Custodial units that steward content managed by the Library's inventory systems are responsible for documenting their approach to resource naming and use of unique identifiers.
- General naming patterns for projects typically follow patterns akin to naming patterns for larger series of content. For example, project names may contain information about the custodian of the content, dates of accession or ingest, title or content information, or unique identifiers.
- If the organization of content reflects the original media object (disk image, file export, etc.), then the original object and the bag should have the same name or a linking identifier.
- Items indexed within the Library's current inventory systems are uniquely identified by pairings of content-manager-generated and system-generated information that creates unique combinations to locate items based on a combination of the project identifier and item or unit identifiers.
Unique identifier schemes are listed by the Library's linked data services at this list of Standard Identifier Schemes. While units are not required to use identifiers from this list, these schemes provide a framework for possible naming conventions.