Re 060119 MMDigest, Archival Media for Digital Data

It seems a number of topics are being discussed.  All are related
but are neither substitutes for each other nor sufficient in and of
themselves.

Fault Tolerance: Steps taken to keep your computer up and running.
Some features supporting fault tolerance include RAID configurations
and disk mirroring.  Timeframe: Immediate.

Back-ups: On & off-site copies of data, including hard copy and digital
copies to hard disk, tape, CD-ROM, and DVD.  Timeframe: short term,
hours to months.

Disaster Recovery: Ability to resume operations after a major loss of
equipment or facility.  Generally requires off-site duplication of
equipment and data.  Disk mirroring is often a component but not
necessarily.  Timeframe: Immediate to days.

Archiving: Long term storage of data includes same media as backups.
Should include multiple copies and storage locations.  Timeframe:
Months, years, decades.  Digital archiving may require conversions
to new media periodically as technologies change and media lifespans
expire.  It may be necessary to "archive" hardware, OS, drivers and
software if antiquated media is not converted to current media.

A comprehensive reference (50 pages!) on the care and feeding of CDs
and DVDs can be found at http://www.itl.nist.gov/div895/carefordisc/
There is also a one-page reference which is probably all most people
need to know: http://www.itl.nist.gov/div895/carefordisc/disccare.html

I'm no expert on media but Memorex (Pro Gold Media) and Kodak have
media with a claimed CD archival life of up to 300 years and a DVD
archival life of up to 100 years. "Armor-plated" media is directed at
discs that will be handled a lot.  Archive copies are rarely handled.

One important feature of successful archiving and disaster recovery is
distance -- physical separation.  Data media, equipment and facilities
should be maintained in different parts of the country.  Hurricanes,
tornadoes, earthquakes, floods, power outages, and nuclear and
biological attacks can affect entire cities or even regions.

Jim Divoky

 [ "Care and Handling of CDs and DVDs: A Guide for Librarians and
 [ Archivists", published jointly by the Information Technology
 [ Laboratory of National Institute of Standards and Technology (NIST)
 [ and the Council on Library and Information Resources (CLIR), may
 [ be viewed at  http://www.clir.org/pubs/abstract/pub121abst.html
 [ -- Robbie