Digital Preservation Policies: Technical Considerations

1
Digital Preservation Policies Technical
Considerations

• SAA Boston 08-06-2004
• Andrea Goethals, FCLA

2
3 Suggestions

• Consider your preservation policy a work in
  progress. Version and date your preservation
  policy.
• Separate the more volatile components of your
  preservation policy from the more stable
  components.
• Keep in mind the fact that computers can be
  time-savers. Automate, Automate, Automate.

3
SOME of the technical considerations

• See your handout for the list
• Focus for today file format decisions

4
File Format

• A usually-documented way a single file structures
  digital content and possibly metadata about that
  content.
• File content (internal metadata) (content)

5
3 File Format Examples
TIFF 6.0
XML 1.0
PLAIN TEXT
6
File Format Decisions in Policy

• Which file formats to use for 'preservation
  copies (not access copies)
• might digitize material to this format
• might convert other digital formats to this
  format
• might create a copy of other digital formats in
  this format
• Requires value judgments on which formats make
  good preservation formats

7
You know a file format is a good preservation
format when

• It accurately represents the real-world
  representation
• Passes the Fidelity Test
• It should be easy to interpret/copy/present/distri
  bute in the future
• Passes the Future Test

8
The Fidelity Test

• Depends on the original input
• Requirements of oral history vs. a symphony
  performance

9
The Future Test

• Single (free?) publicly-avail. spec. from a
  reliable source
• Short clear specification
• Simple format
• Includes technical metadata needed to interpret
  the content
• Avoids codecs, etc. that require license fees,
  etc.
• Relatively long history of use, well-supported
• Completely self-sufficient, no external file
  dependencies
• Doesnt lose info during a copy-to this format
• Not dependent on the original input

10
Fidelity Test ! Future Test

• A format that fails the Fidelity Test can ace
  the Future Test.
• In the future you can perfectly support a poor
  representation of the input. (Bad)
• A format that aces the Fidelity Test can fail
  the Future Test.
• In the future you can't support a faithful
  representation of the input. (Bad)
• A format that aces the Fidelity Test can ace
  the Future Test.
• In the future you can perfectly support a
  faithful representation of the input. (Good)

11
Tiff 6.0 takes the Future Test

• Single (free?) publicly-avail. spec. from a
  reliable source Yes, freely available from
  Adobe's website
• Short clear specification Yes 121 well-written
  pages
• Simple format Yes
• Includes technical metadata needed to interpret
  the content Yes, Image File Header and one or
  more Image File Directories
• Avoids codecs, etc. that require license fees,
  etc. Maybe, if you avoid certain codecs (ex
  LZW in TIFF)

12
Tiff 6.0 takes the Future Test

• Relatively long history of use, well-supported
  Yes, since Summer 1992, good support
• Completely self-sufficient, no external file
  dependencies Yes
• Doesnt lose info during a copy-to this format
  Yes if you avoid lossy compression (ex JPEG in
  TIFF)
• RESULT Tiff 6.0 aces the Future Test as long as
  the codecs used in the Tiffs are restricted.

13
FCLA Action Plans
14
(No Transcript)