Difference between revisions of "4.1 FUNCTIONAL MODEL"
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4.1.2 DATA FLOW DIAGRAMS
Revision as of 12:52, 13 August 2015
The OAIS of figure 2-1 is separated in figure 4-1 into six functional entities and related interfaces. Only major information flows are shown. The lines connecting entities identify communication paths over which information flows in both directions. The lines to Administration and Preservation Planning are dashed only to reduce diagram clutter.
Figure 4-1: OAIS Functional Entities
The role provided by each of the entities in figure 4-1 is described briefly as follows:
The Ingest Functional Entity (labeled ‘Ingest’ in the figures in this section) provides the services and functions to accept Submission Information Packages (SIPs) from Producers (or from internal elements under Administration control) and prepare the contents for storage and management within the Archive. Ingest functions include receiving SIPs, performing quality assurance on SIPs, generating an Archival Information Package (AIP) which complies with the Archive’s data formatting and documentation standards, extracting Descriptive Information from the AIPs for inclusion in the Archive database, and coordinating updates to Archival Storage and Data Management.
The Archival Storage Functional Entity (labeled ‘Archival Storage’ in the figures in this section) provides the services and functions for the storage, maintenance and retrieval of AIPs. Archival Storage functions include receiving AIPs from Ingest and adding them to permanent storage, managing the storage hierarchy, refreshing the media on which Archive holdings are stored, performing routine and special error checking, providing disaster recovery capabilities, and providing AIPs to Access to fulfill orders.
The Data Management Functional Entity (labeled ‘Data Management’ in the figures in this section) provides the services and functions for populating, maintaining, and accessing both Descriptive Information which identifies and documents Archive holdings and administrative data used to manage the Archive. Data Management functions include administering the Archive database functions (maintaining schema and view definitions, and referential integrity), performing database updates (loading new descriptive information or Archive administrative data), performing queries on the data management data to generate query responses, and producing reports from these query responses.
The Administration Functional Entity (labeled ‘Administration’ in the figures in this section) provides the services and functions for the overall operation of the Archive system. Administration functions include soliciting and negotiating submission agreements with Producers, auditing submissions to ensure that they meet Archive standards, and maintaining configuration management of system hardware and software. It also provides system engineering functions to monitor and improve Archive operations, and to inventory, report on, and migrate/update the contents of the Archive. It is also responsible for establishing and maintaining Archive standards and policies, providing customer support, and activating stored requests.
The Preservation Planning Functional Entity (labeled ‘Preservation Planning’ in the figures in this section) provides the services and functions for monitoring the environment of the OAIS, providing recommendations and preservation plans to ensure that the information stored in the OAIS remains accessible to, and understandable by, the Designated Community over the Long Term, even if the original computing environment becomes obsolete. Preservation Planning functions include evaluating the contents of the Archive and periodically recommending archival information updates, recommending the migration of current Archive holdings, developing recommendations for Archive standards and policies, providing periodic risk analysis reports, and monitoring changes in the technology environment and in the Designated Community’s service requirements and Knowledge Base. Preservation Planning also designs Information Package templates and provides design assistance and review to specialize these templates into SIPs and AIPs for specific submissions. Preservation Planning also develops detailed Migration plans, software prototypes and test plans to enable implementation of Administration migration goals.
The Access Functional Entity (labeled ‘Access’ in the figures in this section) provides the services and functions that support Consumers in determining the existence, description, location and availability of information stored in the OAIS, and allowing Consumers to request and receive information products. Access functions include communicating with Consumers to receive requests, applying controls to limit access to specially protected information, coordinating the execution of requests to successful completion, generating responses (Dissemination Information Packages, query responses, reports) and delivering the responses to Consumers.
In addition to the entities described above, there are various Common Services assumed to be available. These services are considered to constitute another functional entity in this model. This entity is so pervasive that, for clarity, it is not shown in figure 4-1.
188.8.131.52 Common Services
184.108.40.206 Archival Storage
220.127.116.11 Data Management
18.104.22.168 Preservation Planning
4.1.2 DATA FLOW DIAGRAMS