1. Digital Preservation Policies: Technical Considerations
SAA Boston:
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/distribute 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
Doesn’t 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
Doesn’t 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