![Digital Records and Digital Archives Preservation in theory and practice Richard Davis Digital Archives Department University of London Computer Centre http://www.ulcc.ac.uk http://ndad.ulcc.ac.uk [email_address]](https://image.slidesharecdn.com/digital-archives-theory-and-practice-1222862491012510-8/85/Digital-Archives-in-Theory-and-Practice-1-320.jpg)
Digital Archives in Theory and Practice
- 1. Digital Records and Digital Archives Preservation in theory and practice Richard Davis Digital Archives Department University of London Computer Centre http://www.ulcc.ac.uk http://ndad.ulcc.ac.uk [email_address]
- 2. What we will cover Preservation options Basic tasks Physical preservation Logical preservation Metadata Organisational issues
- 3. Why do they need special attention? Digital records require an intermediary They don’t have a fixed form Their carriers are perishable They fall outside records management regimes Computers need “experts”
- 4. What are the advantages of digital preservation? Ease of copying Ease of re-use No worry about which is “original” Takes up less space Easy to search, even without a catalogue
- 5. Assumptions You know what digital records exist You know what you want to preserve You have a retention/disposal policy You can separate material for preservation You know what you want to do with it
- 6. Preservation options Preserve the bits Preserve the data Preserve the record Preserve the experience
- 7. Preserving the bits Keep the data in exactly the same format Interpretation likely to be a problem Works in some contexts Mostly useful as an adjunct to other strategies
- 8. Preserving the data Keep the essential data in generic form Don’t worry about presentation and context Better than nothing Often used for databases Reduces long-term utility
- 9. Preserving the record Keep the information and context The ideal approach Don’t necessarily preserve appearance Balances utility against costs
- 10. Preserving the experience Keep everything - software, information, forms, etc May require emulators or old computers Expensive Doesn’t support/promote re-use Someone may do it - but not us!
- 11. Basic tasks in digital preservation Protecting the media Copying to new media Choosing a file format Migrating to new file formats Managing metadata
- 12. Physical forms Floppy disks Open-reel tapes Tape cartridges Hard disks CD-ROM ZIP, JAZ, etc. disks Punched cards, paper tape
- 13. Media lifespans
- 14. Refreshing media The process of copying to new media At end of predicted lifetime At regular intervals After detected failure Lifetime may be number of uses, not interval Maybe the same, maybe different Check all copies
- 15. Logical preservation Selecting right file format At time of creation or accession No universal solution Preservation format may be different from access format Should include metadata
- 16. Properties of preservation formats Published standard Stability Good conversion from ingest formats Good conversion to access formats Good representation of structure of information
- 17. Long-term storage Documents: Plain text, PDF, XML Data tables (DBMS or spreadsheet): CSV, SQL Schema, XML Schema Pictures: TIFF Sound: PCM, AIFF Avoid lossy compression
- 18. Capturing the record Manual Users must choose what is retained User-driven conversion Automatic System forces capture of record copy Triggers conversion to preservation format Retrospective archiving is manual, by definition ERMS should support automated capture
- 19. Automated capture Email: central server captures and indexes Documents: EDMS Databases: capture transaction logs and/or regular snapshots Web sites: as databases Custom applications: specify requirements ab initio
- 20. Migration Frequency is not predictable Usually driven by external factors Changes in IS/IT strategy Software/hardware upgrades Should be automated Check migration does not lose information
- 21. Metadata Data about data Not specific to digital records Types of metadata: Discovery Access Preservation System Embedded or external Treat with same care as data itself!
- 22. Typical metadata Author Subject Keywords Abstract Dates of creation/use/retirement Access conditions Retention period
- 23. Non-digital metadata Most computer systems depend on paper records to be understood: Specifications Manuals Reports Some essential information may only be in people’s heads Especially true for older systems/records
- 25. Preservation and access Preservation systems: Keep information safe and secure Control accessibility Deliver data without interpretation Access systems: Mediate between user and preservation system Format, select and present information Enable user discovery of resources Relate information to context
- 26. Working with IT departments Style of IT support depends on size/age/type of organisation Central control is easier to work with Try to be involved before records are created Express needs/issues in clear, real-world terms IT developers like simple, reusable formats as well
- 27. Hints and tips Databases: may have different views Beware of … Password-protected files Automated dates in documents Dynamic documents Linked documents Embedded objects Hybrid assemblies
- 28. Hybrid assemblies and embedded objects
- 29. And finally… For now: preserve original bitwise copies and use standard formats Don’t wait for all the answers before you begin Make friends with IT specialists Learn about other initiatives and approaches Remember your Records Management training: digital isn’t that different