Keeping the pieces together: The Role of METS in the Preservation of Digital Content Robin Wendler Harvard University Library January 16, 2005 [Men in crate looking up, photograph, ca Harvard University Archives HUK 363 p (Fig. 8) ]

Standards everywhere, but nothing there for me… As of 2000 –A plethora of descriptive metadata standards –Emerging standards for digital conversion, BUT –No open standard for representing a digital object Display and navigation Archiving Exchange / Transport –Digital repositories managing files, not objects

OAIS Functional Entities

OAIS Information Model

METS to the rescue Metadata Encoding and Transmission Standard –An XML schema for encoding descriptive, administrative, and structural metadata about a digital object – –An initiative of the Digital Library Federation –Development: METS Editorial Board –Principle author: Jerome McDonough, NYU –Website maintained by: Library of Congress

METS Basics METS provides a framework for –Content files –Metadata –Relationships Suitable for –Open Archival Information Systems Archival information package (AIP) Submission information package (SIP) Dissemination information package (DIP) –Display and navigation of digital objects –Sharing of digital objects among libraries and archives

Structure of a METS File METS metsHdr structMap admSec dmdSec fileSec structLink behaviorSec* Inventory or manifest of component files Header describing METS file itself Descriptive metadata Administrative metadata: -- technical, source, rights, provenance Structure map: the heart of METS Structural map linking, i.e., hyperlinks Executable behaviors * Not commonly used

Structure Map Title page Preface page i page ii Chapter 1 page 1 page 2… <div LABEL=“title page” ORDER=“1” TYPE= FILEID=“C”> …

Referring to Metadata METS metsHdr structMap admSec dmdSec fileSec structLink behaviorSec METS does not define descriptive or administrative metadata elements. dmdSec and admSec are buckets or sockets where externally-defined metadata can be supplied or referenced Three techniques: In-line XML Wrapped base-64 encoded data Pointers to external information (e.g., URNs, handles) METS Board endorses range of recommended “extension schemas”

Book Chapter 1 page 1 page 2… … <mods:mods xmlns:mods=" xsi:schemaLocation= …> … Radcliffe College Reports of the president and treasurer for... BNI3165 Use of MODS Extension Schema for Descriptive Metadata Catalog record Catalog record

Referring to Content Files METS metsHdr structMap admSec dmdSec fileSec structLink behaviorSec Digital Content can exist inside or outside a METS file. Three techniques: In-line XML Wrapped base-64 encoded data Pointers to external information (e.g., URNs, handles)

Structure Map Chapter 1 page 1 page 2… … image/jpg big-endian <… Use of MIX Extension Schema for Image Technical Metadata

Profiles Challenge: –METS is very flexible –Flexibility allows variant practices –Variant practices undermine interoperability Response: –Create profiles: documented ways of using METS Profiles constrain practice (this is a good thing) Specify required structures, extension schemas, vocabularies, etc. –Communities of interest develop and register shared profiles –XML schema for METS profiles Human-readable, not machine-actionable

Adoption Library of Congress California Digital Library Harvard University Library Oxford University MIT/DSpace National Library of Wales Stanford University Library Indiana University Library University of California, Berkeley University of Chicago Library University of Graz, Austria Florida Center for Library Automation Göttingen State and University Library OCLC Digital Archive RLG Cultural Materials Philadelphia Museum of Art University of Alberta … among others Used By:

Benefits Modeling the whole object, not just files Open standard + XML encoding + Growing base of tools = Manageable, sharable, preservable digital objects

Thank You! Robin Wendler Baker Library, Harvard Business School, Historical Collections TC :6512