H ARVARD U NIVERSITY L IBRARY The Global Digital Format Registry (GDFR) Project Stephen Abrams...

HARVARD UNIVERSITY LIBRARY

The Global Digital Format Registry(GDFR) Project

Stephen AbramsHarvard University

Andreas StanescuOCLC

CNI Fall Task Force MeetingWashington, DC, December 10-11, 2007


Digital preservation and format

• Preservation is concerned with ensuring access to managed digital assets over time

• Thus, preservation activities are focused on

– Viability– Fixity– Authenticity– Interpretability– Renderability

• The last two are primarily a function of format


Without format typing, all content is opaque

ffd8ffe000104a46494600010201008300830000ffed0fb050686f746f73686f7020332e30003842494d03e90a5072696e7420496e666f000000007800000000004800480000000002f40240ffeeffee030602520347052803fc00020000004800480000000002d80228000100000064000000010003030300000001270f0001000100000000000000000000000060080019019000000000000000000000000000000000000000000000000000000000000000003842494d03ed0a5265736f6c7574696f6e0000000010008313a3000200 ...


Without format typing, all content is opaque

ffd8ffe000104a46494600010201008300830000ffed0fb050686f746f73686f7020332e30003842494d03e90a5072696e7420496e666f000000007800000000004800480000000002f40240ffeeffee030602520347052803fc00020000004800480000000002d80228000100000064000000010003030300000001270f0001000100000000000000000000000060080019019000000000000000000000000000000000000000000000000000000000000000003842494d03ed0a5265736f6c7574696f6e0000000010008313a3000200 ...

SOIAPP0 JFIF 1.2APP13 IPTCAPP2 ICCDQTSOF0 183x512DRIDHTSOSECS0RST0ECS1RST1ECS2...


Global Digital Format Registry

“The Global Digital Format Registry (GDFR) will provide sustainable services to collect, review, store, discover, and deliver significant representation information about digital formats.”

– Centrally-organized collection and review

– Distributed storage, discovery, and delivery on a network of independent, but cooperating registries


What is a format?

• “A serialized encoding of an abstract information model”

• Encompasses the nominal sense of “file format” as well as a range of conceptual entities from the micro to the macro level

– IEEE 754 floating point number– File system– In both case, there are well-defined syntactic and

semantic rules for mapping from information to bits, and back again


What’s wrong with MIME types?


What’s wrong with MIME types?

• Non-standardized documentation

• Intended for human, not machine consumption

• Coarse granularity– image/tiff vs. TIFF 4.0 – 6.0

Baseline Class B, G, P, RExtension Class YTIFF/EPTIFF/IT with file types CT, LW, HC, MP, BP, BP, BL,

FPExif 2.0 – 2.2GeoTIFFTIFF/FXDNG


GDFR project

• Two DLF-sponsored invitational workshops

– University of Pennsylvania, January 2003– Washington, March 2003

• Two independent demonstration projects

– FRED [John Ockerbloom, University of Pennsylvania]tom.library.upenn.edu/fred/

– FOCUS [Joseph JaJa, University of Maryland]www.umiacs.umd.edu/~joseph/focus-archiving06.pdf

http://tom.library.upenn.edu/fred/

http://tom.library.upenn.edu/fred/

http://www.umiacs.umd.edu/~joseph/focus-archiving06.pdf


GDFR project

• Harvard University Library (HUL) funded for 2 years by the Andrew W. Mellon Foundation

• Staffing and technical work subcontracted by HUL to OCLC (July 2006)


GDFR project oversight

• Technical Working Group (TWG)– Bibliothèque nationale de France– British Library– California Digital Library– Digital Curation Centre, UK– Library of Congress– National Archives, UK– National Archives and Records Administration– National Library of Australia– National Library of New Zealand– Stanford University– University of Pennsylvania


General development goals

• A generalized registry framework, specialized for the distributed GDFR application

• Based on well-known products and protocols

• Human and machine interfaces

• Full information content expressible in XML form, and can be re-instantiated from that expression

• Platform independence

• Globally fault tolerant

• Open source


GDFR data model

• Consistent with PRONOM registry

Media

Agent

Software

Hardware

Document

dependencies

author, owner, maintainer

documentation

Format

Identifier Name Version Classification Description ReleaseDate WithdrawalDate Rights Signature Byte order Grammar Assessment

Relationship


Identifiers

• Canonical, GDFR-assigned identifier

– “info” URI info:rfa/gdfr1/Formats/1

• Other well-known identifiers

– Common name “TIFF”, “Tagged Image File Format”

– MIME type image/tiff

– PRONOM identifier info:pronom/fmt/7

– Library of Congress Format Description Document (FDD) identifier fdd000022


Classification scheme

• Eight facets

– Genre (required) text, still-image, sound, aggregate, …

– Role (required) family, file-format, encoding, serialization

– Composition unitary, container-bundle, container-wrapper

– Form binary, text

– Constraint structured, unstructured

– Basis sampled, symbolic

– Domain astronomy, cad-cam, gis, web-archive, …

– Transform compression, encryption, message-digest, …


Classification scheme

• Examples

– TIFF (Tagged Image File Format) genre:still-imagerole:familycomposition:container-

wrapperform:binarybasis:sampled

– LZW (Liv-Zempel-Welch) genre:still-imagerole:encodingtransform:compression

– SVG (Scalable Vector Graphics) genre:still-imagerole:file-formatform:textbasis:symbolic


Signatures

• External signatures

– File extension– Mac OS type– Mac OS X Uniform Type Identifiers (UTI)

• Internal signatures

– “Magic numbers”– Required vs. optional– Fixed vs. restricted vs. unrestricted


Grammar

• Formal description of the syntactic grammar underlying a format, expressed in some formal typed notation

– BNF Backus-Naur Form

– BSDL MPEG-21 Bitstream Syntax Description Language

– DFDL Data Format Description Language

– EAST CCSDS 644.0-B-2

– XCEL Extensible Characterisation Extraction Language


Assessment

• Assessment of a format, expressed in some formal typed notation

– Cornell Virtual Remote Control (VRC)

– DTSC PANIC

– Library of Congress Sustainability, Quality, Function (SQF)

– National Library of Australia AONS

– OCLC INFORM


Documentation

• Specification documents (and software files) can be managed and distributed in the network

– Applicable only in cases of public domain resources or if explicit permission is granted by rights holders

– Other documents (and software) will be referenced by full citation, including actionable links where possible

– Mechanism for individuals or institutions to register locally-held copies, with terms of use


Software

• Format role Input, output

• Process type Characterize, create, edit, identify, …

• Enables discovery of transformative processing chains

PDF Postscript ASCII

Transformpdf2ps

RenderNotepad

Transformps2ascii


Relationships

• Modification BWF → WAVE

– Extension DNG → TIFF 6.0

– Restriction PDF/A → PDF 1.4

• Definition NITF → XML DTD

• Requisite XML → Relax NG

• Containment ZIP → *

• Equivalence DXF (ASCII) → DXF (binary)

• Version Word 97 → Word 6.0

• Affinity SPIFF → JPEG


GDFR node

• Based on the OCLC IWSA / RFA framework

Canonical service layer

SRU/W OAISRU Update RSS Atom

XML RDBMS

Public service layer

Storage layer

Collection layer

Add DeleteUpdate Search

TCP/IP

AtomSRU/W

Display AdminDataContent History Export Import

Create


GDFR node

• Java, Apache/Tomcat, Berkeley DB XML

• GNU LGPL license

– Including pre-existing OCLC technology and technology newly-developed for the project

• Release schedule

– v0.1 (alpha) March 23, 2007– v0.1 (beta) June 14, 2007– v1.0 June 30, 2007– v1.1 August 12, 2007– v1.3 September 17, 2007– v1.3.1 October 26, 2007


GDFR node


GDFR network

• Peer-to-peer network of independent, but cooperating registries communicating over a common protocol

RootGDFR node

GDFR node

GDFR node

GDFR node

Editorial process

Submissions for technical vetting

Vetted for propagation

GDFR protocol

Data propagation


GDFR network

• Public notification of the availability of new data

– RSS feed available at well-known public address to which remote nodes can subscribe

• Remote harvesting of local data

– OAI-PMH (Open Archives Initiative Protocol for Metadata Harvesting)

• Initially, a single source (root node) for all new data


Project status

• Extensive internal testing of GDFR software in a stand-alone mode

• Current project activities are focused on

– Implementing the distribution and synchronization functions

– Building the network– Data acquisition– Succession planning


Initial population

• Manual addition is possible, but time consuming

• Automated update using Atom

• What sources are available for bulk population?

– PRONOM registry www.nationalarchives.gov.uk/pronom

– Library of Congress Format Description Documents (FDD) www.digitalpreservation.gov/formats/fdd/descriptions.shtml

– Unix / Linux magic(4) database

http://www.nationalarchives.gov.uk/pronom

http://www.digitalpreservation.gov/formats/fdd/descriptions.shtml


Subsequent population

• RFC 2026, Internet Standards Processwww.ietf.org/rfc/rfc2026.txt

– “Iterations of review by the ... community and revision based upon experience”

• Draft distribution and public discussion

• Approval by “area” editors

• Release to the network for distribution

http://www.ietf.org/rfc/rfc2026.txt


Sustainability

• The technological solution is the (relatively) easy part, but…

– The technology is expendable

– The important point is for the data to survive, evolve, and expand


Governance and succession

• Mellon funding was for technical work only

• At the end of the two year project…

– Harvard will continue maintenance for up to two years– Library of Congress has agreed to be a care-taker

agency until a permanent body is identified


Governance and succession

• NARA GDFR governance investigation

– Part of the Electronic Records Archives (ERA) initiative

– GDFR Governance Workshop, November 2007

• Bibliothèque et Archives, Canada • NARA• Corp. for National Research Initiatives • NASA• Digital Curation Centre, UK • NIST• Digital Library Federation • National Library of Australia• General Services Administration • National Library of New

Zealand• Georgia Institute of Technology • San Diego Supercomputer

Center• Government Printing Office • Stanford University• Harvard University • Statens Archiv, Sweden• IBM Watson Research Center • Tessalla Support Services• Koninklijke Bibliotheek, Netherlands • University of Pennsylvania• Library of Congress• MIT


Administrative considerations

• Policy

– Who (and how many) can join the network?– What are the eligibility requirements?– What are the rights and obligations of membership?

• Technical

– Who will maintain and enhance the data model?– Who will maintain, enhance, distribute, and support

the software?


Administrative considerations

• Data

– Who will contribute data?– Who will vouch for data authenticity?– Who will ensure data integrity?

• Financial

– What are the real human and system costs associated with GDFR operation?

– Who pays, and how?


Summary

• The GDFR is an enabling technology that will support digital repository and preservation activities

– Supports the strong typing of digital assets at an appropriate level of granularity

– Enables the future recovery of the syntax and semantics associated with typed digital assets

– A means to pool and redistribute the expertise of the international digital preservation community


For more information…

www.formatregistry.org

[email protected]

[email protected]

http://www.formatregistry.org/

mailto:[email protected]

mailto:[email protected]

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