Concepts behind OAIS

Archive Task TeamWGISS 23

May 21 – 25, 2007Hanoi, Vietnum

OAIS OAIS – Open Archival Information System Created by Consultative Committee for

Space Data Systems (CCSDS) to standardize basic functionalities of any archive system

Defines components and interactions of a full-featured stand-alone archive

Organized by function 7 key functional areas 33 specific functions defined

OAIS Organization

Administration

ArchivalStorage

DataManagement

Ingest Access

Preservation Planning

CentralServices

SIPAIP AIP

DIP

Identifies essential functionalities Provides a standard vocabulary Improves interoperability between archives Does not help much in consideration of multiple archives within one facility

A different view of OAIS

Try to improve usefulness by reorganizing based on data format: Data items are contained in packages Three different formats for data package:

SIP (Submission Information Package) AIP (Archival Information Package) DIP (Distribution Information Package)

Most pieces of information will live in all three formats at different times

Information Package

Content Data Object(CDO)

RepresentationInformation

(RI)

Content Information(CI)

PreservationDescription Info

(PDI)

InformationPackage

(IP)

DescriptiveInformation

Knowledge to beconveyed or stored

Makes CDOunderstandable in

knowledge base of thedesignated community

Provenance,Reference, Fixity, and

Context of CI

The informationobject

Used for discovery ofpackage of interest

Packaging Information

Binds ContentInformation and PDI

IP-based view of OAIS archive

Three main regions Archive Core performs stewardship on data; AIP data is “context-free” Mission “wrapper” interacts with data providers and converts SIP to AIP Consumer Access interacts with customers and converts AIP to DIP

Operate within an environment Execution provides direction, care and feeding Environment is functionality required to support operations

ArchiveCore

Mission

ConsumerAccess

Environment

Execution

SIP AIP

AIP

DIP

DataProduction

Focus of Responsibility Archive Core

Problem space: Technology solutions as they relate to data integrity and system performance

Isolation from data provider and customer concerns allows focus on underlying technology

Mission “wrapper” Problem space: Primarily that of the data provider Negotiates SIP format for data providers and converts SIPs into AIPs for

archival Consumer Access

Problem space: Customer Provides catalog, data access, billing and accounting, customer service,

outreach Execution

Problem space: Operation of the archive Provides tactical business execution, O&M

Environment Problem space: Archive support Functionality that enables and supports an operational archive

Archive Core Considerations A major part of the archive that deals with data only in an

AIP format, isolated from concerns about data providers or downstream customers

Data is context-neutral so design of this part of the system can be generic Allow reuse, possible COTS solutions Focus technical resources on technology to allow better

tracking of emerging technology trends Technology Refresh – In most digital archives, technology

becomes obsolete within the required lifetime of data within an archive. With a standard interface to other parts of the system, it is possible to change out the Archive Core without impacting data providers or consumers

Only characterized by: Type (Active, short-term, long-term, etc.) Capacity Performance

Benefits in single archive environment

Put skill focus where appropriate Archive Core specialists focus on data security, emerging

technology and methodologies, performance Execution staff focus on the archive business mission and

standardized administration Improve quality

Mission specialists focus on the data provider Consumer Access specialists understand the needs of the

customer Enabler of state-of-the-art implementations

Tracking emerging technology is a huge and expensive undertaking. By focusing responsibility of Archive Core staff, it becomes easier to implement advanced technologies that will be required in the future (operational automation, automated fault detection/recovery).

COTS solutions could amortize cost across many archive systems, making it much cheaper than custom designs

Multi-archive environment

Deploy and optimize Archive Cores based on archive types needed in the facility rather than by mission

Faster and easier to deploy new missions Multiple missions can share system resources

Reduce complexity Reduce expense and system footprint Reduce operational and maintenance expense

Improve interoperability and control

ArchiveCore 1

(Short-term)

Mission

ConsumerAccess

Environment

Execution

ArchiveCore 2

(Long-term)

ConsumerAccess

Support multiple missions

With a new mission, have the choice of building an entire new archive or attaching to an existing Archive Core If already have an Archive Core that provides the required type of

storage: Make a wrapper to attach to the existing Archive Core If necessary, grow Archive Core capacity to accommodate new

archive growth Add schema to the catalog Only new development would be if it has a new SIP that you don’t

currently handle Already have staff and resources in place – just add mission specialists

SIP

Data Provider1

SIP

Data Provider2Consolidated

ArchiveCore

ConsumerAccess

Environment

Execution

Efficient Data Migration

Assuming a standard AIP format, migration merely involves changing the Packaging Information, moving the data and populating catalog

Environment

Execution

ArchiveCore 2(LTA)

ConsumerAccess

ArchiveCore 1(active)

ConsumerAccess

MigrationEngineAIP AIP

Possible Enhancements to OAIS

OAIS model is fairly new (Jan. 2002) and is still evolving

Enhancements that would be beneficial: Define interfaces to allow clients and

external catalogs to “plug in” to the archives

Allow for hybrid architectures

Comments and Suggestions?

Any next steps? How ATT contribute to GEO? Does WGISS want to explore moving

toward? What are the mutual advantages?

Does ATT should continue? Close? Unify to other TT ? Open ATT

once a year?