6.1.4 ARCHIVES WITH SHARED FUNCTIONAL AREAS
In an association involving Archives with shared functional areas, Management has entered into agreements with Archives to share or integrate functional areas. The motive for this may be to share expensive resources such as hierarchical file management system for Archival Storage, peripheral device for Ingest or dissemination of Information Packages or supercomputers for complicated transformations between SIPs, AIPs or DIPs. This association is fundamentally different from the previous examples, in that it is no longer possible to ignore the internal architecture of the Archive.
Figure 6-4 illustrates the sharing of a common storage function, consisting of an Archival Storage entity and a Data Management entity, between two Archives, OAIS 1 and OAIS 2. The Access and Ingest facilities can be at any of the previously described levels of inter- operability. In fact, each Archive can serve totally independent communities as implied in this figure. However, for the common storage element to succeed, standards are needed at the internal Ingest-storage and Access-storage interfaces.
Additional potential shared services include registries of Representation Information and name resolvers such as the DNS. In the former case a registry of Representation Information should also be an OAIS and the Representation Information it holds should be part of the Content Information it holds. The Representation Information it holds might, for example, be part of the Representation Network for the Content Information within an AIP in another OAIS. In such a case the OAIS holding that AIP may cache copies of the Representation Network held in the registry. Whether it does so or instead relies on the registry to maintain the Representation Network, the ultimate responsibility for the understandability of the Content Information remains with the OAIS which holds the AIP.
Figure 6-4: Archives with Shared Storage