Curation Storage Service

The curation Storage micro-service provides a robust, flexible, and easily deployed environment in which to manage the secure and persistent storage of encoded files that represent digital content. The Storage service models digital content in terms of four conceptual entities:

• Node. A set of objects.
• Object. A set of versions.
• Version. A set of files representing a discrete state of an object.
• File. An encoded byte stream.

The Storage service supports a set of behaviors for manipulating and retrieving these entities and their properties. Interaction with the Storage service is provided via a java procedural API, a command line API, and a RESTful web API. More ...

Consistent with the general micro-service principles of orthogonality and granularity, the Storage service itself relies on a number of independent subsidiary components.

CAN: Content Access Node

CAN is a file system convention for storing digital objects. It imposes minimal architectural and policy constraints while reserving a small set of file system names (directories and files) that place salient object store features in well-known locations within a single directory hierarchy that comprises the object store. Multiple CANs may be instantiated within the Storage service to reflect various technological and policy choices. More ...

Pairtree: Object Storage

Pairtree is a file system convention for the organization of a digital object store. Objects are located within a store hierarchy by mapping identifier strings to object directory (or folder) paths two characters at a time. The mapping is reversible, so a traversal of a Pairtree reliably enumerates all the contained object identifiers. Pairtrees have the advantage that many object operations, including backup and restore, can be performed with native operating system tools. More ...

Dflat: A Simple File System Convention

Dflat is a file system convention for storing a digital object. It imposes minimal architectural and policy constraints while reserving a small set of file system names (directories and files) that place salient object features in well-known locations within a single directory hierarchy that houses the object. For purposes of Dflat a digital object is defined as a versioned set of files. More ...

ReDD: Reverse Directory Deltas

ReDD is a system for file-level reverse delta compression of versioned sets of files. More ...