Enabling Access (CPP-025)

Definition and scope

Data access in digital preservation refers to the ability to retrieve, view, and use preserved digital materials in meaningful ways over extended periods of time. The access as a whole involves several aspects. This CPP concentrates on the aspects within technical accessibility, and leaves out aspects like Enabling Discovery (CPP-024) and delivery methods (e.g. user interfaces and APIs). A TDA must implement access to the data it preserves to consumers that are authorised to access the data in question.

Technical accessibility means ensuring that digital Files remain readable and usable despite technological change. This requires maintaining compatibility with current systems through File Migration (CPP-014), emulation strategies (CPP-015 Emulation and Rendering Tools), or preservation of legacy hardware and software environments. The preserved data must be retrievable from storage systems and renderable in forms that users can actually engage with.

From a technical point of view, Enabling Access is about providing DIPs containing the requested data in appropriate Representations. The TDA, upon receiving a request, creates and provides a DIP from one or more AIPs stored in the TDA. The TDA also, if it supports this, provides access to derivatives that are Representations of the preserved data that are specifically created for use, viewing, or interaction, rather than giving them access to the master data. The derivatives can be created at different stages of digital preservation: in pre-ingest phase, during ingest, within the preservation lifespan, or on the fly when the derivative is needed. This approach is TDA-dependent and can be enforced by a policy. In any of these cases, however, the access process should always provide the data in the form of a DIP by a TDA to a consumer (e.g. end user; portal or aggregator; data publication platform or some other service or system communicating with the TDA).

The accessed data may include restrictions or sensitive, confidential or rights-protected parts (CPP-020 Rights Management). Also, an organisation’s data can be non-public, and/or non-accessible for other organisations. Therefore, access should incorporate authentication and authorisation functions to control who can access what data, implementing necessary restrictions while enabling legitimate use. Restrictions on accessing data (particularly digital Objects) are usually different from restrictions to find and discover data (CPP-024 Enabling Discovery).