The data curation consists of taking all the necessary measures to ensure that the data remains intact, reeadable and authentic over time. As far as digital information is concerned, the fight against obsolescence is particularly important and leads to fairly rapid rates of media migration, hardware and system changes and format transformations. Another characteristic of digital information is that, since the information is encoded, additional efforts must be made to describe this encoding and to maintain this description over time.
The archive services in charge of this responsibility use techniques such as hash codes, time stamping, sealing, redundancy... Technological and economic monitoring is also an important part of their work. From an organisational point of view, they must ensure the security and traceability of their operations. The OAIS conceptual standard describes an organisational model to which many organisations refer. The TGIR Huma-Num permanent archive service has followed this model.
The Cocoon data archiving
COCOON was involved in the design in 2008 and then the implementation in 2010 of the long-term preservation service of the TGIR Huma-Num. This service is built according to the ISO OAIS standard model. It is based on two computing centres: the CINES (Centre Informatique National de l'Enseignement Supérieur) as the primary site and the IN2P3 (Institut National de Physique Nucléaire et de Physique des Particles) as the secondary site. The role of COCOON (at the time CRDO-Paris) is that of a service depositing data on behalf of producers, and that of an access service for users.
All Cocoon's resources are archived by CINES (Huma-Num's archiving operator). The only exceptions are those resources that are already archived at the french national archives "Archives Nationales" or at the "Bibliothèque nationale de France". In all these cases, the organisational model used by these operators is the one described in the OAIS conceptual standard.
Open Archival Information System (OAIS)
The OAIS corresponds to ISO 14721:2003 (revised 2012) - "Reference Model for an Open Archival Information System". It is the result of a working group of the Consultative Committee for Space Data Systems (CCSDS), initially bringing together the major space agencies and later extending to other areas such as institutional archives or libraries.
The OAIS presents a conceptual model that defines the structure of an archiving system as follows:
- A functional model including the different entities (entry, storage, data management, administration, preservation planning and access);
- Actors (producers, archive, users, management);
- An information model with representation information (syntactic and semantic), preservation information (identification, provenance, context, integrity) and packaging information;
- A definition of information packages: SIP Submission Information Package, AIP Archival Information Package, DIP Dissemination Information Package.
- A lexicon associated with all these concepts