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Born-digital collections present a challenge to traditional ways of describing content and making it discoverable. Disks, drives, directories, etc. may contain many thousands of files which would be difficult to describe in detail in an EAD. The approach described here starts with an EAD that contains only a single reference to the born-digital portion of a collection, expressed as a specific Series within the larger collection. The Forensic Toolkit (FTK) software is used to produce both disk images and related analysis files, plus detailed technical information about individual files on the media. The output of this process is augmented, transformed, and eventually transformed translated into a set of digital objects in DOR (Stanford's Fedora-based Digital Object Registry) and shared objects for Hypatia.

A separate process is used for converting the Collection EAD into metadata objects representing the full context of the born-digital and other materials, with links made between the containers and the detailed objects.

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The Stanford Stephen J. Gould collection will be used to describe the initial implementation of this process. It is believed to represent a template for similar work with other born digital collections going forward.

The directory output for the Gould collection contains the EAD and the content and metadata files for both Media and file objects (irrelevant files not shown):

M1437 Gould
- Computer Media Photo
  - CM001.jpg
  - (etc)
- Disk Image
  - Wiki Markup
    CM001.001\[.dd\]
  - CM001.001.csv
  - CM001.001.txt
  - (etc)
- Display Derivatives
  - {filename}.htm
- EAD
- FTK xml
  - files
    - {filename}
  - Report_transformed.xml
  - Report.fo
  - Report.xml

Note that the first 2 directories map to objects describing the physical media and will be the source of creating the "unprocessed" collection, while Display Derivatives and FTK files map to individual file content & description and will be used to create the "processed" collection.

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The Import/conversion process will produce this arrangement of objects in DOR:

Collection object
- Series set -- Series 1 ..."
- :
- Series set -- "Series 6: Born Digital Materials"
  - Media object 1 Media object 2
    - :
    - - File object 1
      .1
      - File object
      1.
      - 2
      - :
    - File object 2.1
    - File object 2.2
    - :
Note that even though the files originate on specific media, the "
- - - Media
" objects are not sets in the DOR/Hydra sense of simple
- - - object
aggregation. Instead, the file/media relationship is considered just one of many possible arrangements that can be expressed in metadata. A RELS-EXT relationship (hydra:isLocatedOn, onSourceMedia???) and a MODS <location> (for humans) express the file and media relationship, allowing this logical view:
- Series set -- "Series 6: Born Digital Materials"
  - Media object 1
    - File object 1
    - File object 2
    - :
  - Media object 2
  - :
... while a simple descriptive elements like <type> allow other logical arrangements of the files based on the nature of their content. Note we are not concerned here how the Colleciton and Series nodes get created, nor how much of the rest of the EAD is also represented in DOR.

Sample of the starting lines of the .txt file describing the media object.

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Each <file> segment will be a the basis of a separate Hypatia Digital Object. This is an example where the atomistic model adds overhead (separate metadata and content objects) and an integrated object combining commonMetadata and genericContent could be considered.

Collection and Series objects

The Collection and Born-Digital Series objects themselves are created first, ahead of FTK processing. All FTK processed materials for a collection are processed together and are members of the Born-Digial Series set. The following information is also contained in a CMnnn.txt file describing a specific disk image

Information from: Disk Image // CMnnn.001.txt	maps to	notes
<collection_title>Stephen J. Gould Papers	Collection object descMetadata <mods:title> Series & item objects descMetadata <mods:location> (1)	Same as EAD <archdesc><title> Note that both the Collection and Series object may originate with the EAD rather than from the FTK output described here.
<series>Series 6: Born Digital Materials	Series set object descMetadata <mods:title> Item objects descMetadata <mods:location> (1)	Same as EAD series <c><unittitle>
<note>5.25 inch Floppy Disks</note>	Series Media object descmetadata <mods:physicalDescription> <mods:extent>	Would correspond to EAD <physdesc> in a node describing the media.
<callnumber>M1437</callnumber>	Collection object descMetadata <mods:identifier type="unitid" displayLabel="Call Number">	Same as EAD <archdesc><did><unitid>

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Information from: FTK xml // Report_transformed.xml	maps to (within item objects)	notes
<filename>BU3A5</filename>	n/a	this is the original file name as it appeared on the original media.
<Item_Number>1004</Item_Number>	n/a	internal FTK reference only, to disambiguate references in the FTK report
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="49b5ead78f8663f8-05882171-4b074f03-a207a3ea-d782d177d5183c3b74aa44b3"><ac:plain-text-body><![CDATA[	<filepath>CM006.001/NONAME [FAT12]/[root]/BU3A5</filepath>		location of file on original media ]]></ac:plain-text-body></ac:structured-macro> <ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="22246e13e7f56d68-82a9f223-41634f6b-97b3a6c7-6278d7cfcd49c2ff6eadb760"><ac:plain-text-body><![CDATA[everything after [root] can be taken as the fully qualified filename	]]></ac:plain-text-body></ac:structured-macro>
<disk_image_no>CM006</disk_image_no>	descMetadata <mods:location> (1)	This token, taken from the head of the <filepath>, is the only data link between the FTK output for a file object and the corresponding media object. We want a data link in descriptive metadata as well as an RDF link to the corresponding object.
<filesize>35654</filesize>		Could be used by conversion to compare against the file size as computed locally, a quick check prior to checksum validation?
<filesize_unit>B</filesize_unit>		Needed to correctly interpret <filesize>, if used
<file_creation_date>n/a</file_creation_date>	note?
<file_accessed_date>n/a</file_accessed_date>	note?
<file_modified_date>12/8/1988 6:48:48 AM (1988-12-08 14:48:48 UTC)</file_modified_date>	note?
<MD5_Hash>976EDB782AE48FE0A84761BB608B1880</MD5_Hash>		Used for checksum validation of a file during processing. This value will eventually be part of contentMetadata, but probably not as a value transferred from here.
<restricted>False</Restricted>		true=visible staff only, not discoverable .... Hypatia only
<type>Books</type>	descMetadata <mods:subject> <mods:topic>	<topic? or <genre>? authority?
<title>The Burgess Shale and the Nature of History</title>	descMetadata <mods:title>
<filetype>WordPerfect 4.2</filetype>	descMetadata <mods:note displayLabel="File type">
<Duplicate_File> </Duplicate_File>		* blank, null value or empty string - file is unique in collection, no duplicates * "M" - The main file in a duplicate relationship. Neither better nor worse than the duplicate file, but simply the file examined first. * "D" - indicates a duplicate file. Note that this is content duplication based on having the same checksum (name conflicts are different and handled another way). The two files may or may not have the same name. It is desirable to have a note and/or relationship in each record indicating the presence of a duplicate file in the collection. Details tbd.
<export_path>files\BU3A5.wp</export_path>		The file as saved by FTK for further processing.

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Collection and Series objects