Digital Data Preservation Digital Data Preservation Research into a - - PowerPoint PPT Presentation

Mar 15, 2007 Mar 15, 2007 Family History Technology Family History Technology 1 1

Digital Data Preservation Digital Data Preservation

Research into a solution for preservation of digital Research into a solution for preservation of digital information information Barry M. Lunt, Ph.D.; Professor, Information Barry M. Lunt, Ph.D.; Professor, Information Technology, BYU Technology, BYU Matthew R. Matthew R. Linford Linford, Ph.D.; Associate Professor, , Ph.D.; Associate Professor, Chemistry & Biochemistry, BYU Chemistry & Biochemistry, BYU Feng Feng Zhang, Ph.D. student; Chemistry & Biochemistry Zhang, Ph.D. student; Chemistry & Biochemistry Ryan Ryan Sydenham Sydenham, B.S student; Mechanical Engineering , B.S student; Mechanical Engineering

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Presentation Outline Presentation Outline

• Defining the Problem

Defining the Problem

• Evidences of the Problem

Evidences of the Problem

• Stimuli toward Research

Stimuli toward Research

• Existing Optical Storage

Existing Optical Storage

• Research Progress

Research Progress

• Conclusion

Conclusion

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Defining the Problem Defining the Problem

• All current methods of storing digital information

All current methods of storing digital information are ephemeral, by historical standards: are ephemeral, by historical standards:

• Magnetic: 30

Magnetic: 30 – – 50 years 50 years

• Optical (recordable): 7

Optical (recordable): 7 – – 23 years 23 years

• Solid state (Flash memory): 10

Solid state (Flash memory): 10 – – 12 years 12 years

• Much modern information has no analog

Much modern information has no analog counterpart counterpart

• Digital information does not gracefully degrade

Digital information does not gracefully degrade

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Evidences: Evidences:

“ “Longevity of CD Media Longevity of CD Media” ” – – Research at the Research at the Library of Congress Library of Congress

• 125 CDs, randomly selected from 60,000 collection

125 CDs, randomly selected from 60,000 collection

All CDs experience the same conditions (normal storage and circulation)

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Evidences: Evidences:

“ “Longevity of CD Media Longevity of CD Media” ” – – Library of Congress Library of Congress Accelerated aging test Accelerated aging test

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Evidences: Evidences: “ “Longevity of CD Media Longevity of CD Media” ” – – Library of Congress Library of Congress Accelerated aging test Accelerated aging test

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Evidences: Evidences:

NIST NIST – – Accelerated aging test, CD Accelerated aging test, CD-

• Rs

Rs

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Evidences: Evidences: NIST NIST – – Accelerated aging test, CD Accelerated aging test, CD-

• Rs

Rs

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Evidences: Evidences: Fred Byers (NIST): Fred Byers (NIST): Accelerated aging test, CD Accelerated aging test, CD-

• Rs

Rs Projected Time to Failure: 14.75 years; 23.09 Projected Time to Failure: 14.75 years; 23.09 years years

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Evidences: Evidences: International Journal for the Preservation International Journal for the Preservation

• f Library and Archival Material
• f Library and Archival Material

The Relative Stabilities of Optical Disc Formats The Relative Stabilities of Optical Disc Formats

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Stimuli: Stimuli: Computerworld Computerworld

• www.computerworld.com/blogs/note/625

www.computerworld.com/blogs/note/625

• Marian

Marian Prokop Prokop, 7/22/05 , 7/22/05 “ “Federal employees involved in preservation and Federal employees involved in preservation and archiving want the optical disks they use to have a archiving want the optical disks they use to have a lifespan of at least 40 years, according to a survey. lifespan of at least 40 years, according to a survey. The Government Information Preservation The Government Information Preservation Working Group is working the National Institute Working Group is working the National Institute

• f Standards and Technology to establish a long
• f Standards and Technology to establish a long-
• term, or archival, standard measurement for

term, or archival, standard measurement for recordable CD and DVD media. recordable CD and DVD media.” ”

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Stimuli: Stimuli: Digital Documents Digital Documents

• Digital photos

Digital photos

• Digital videos

Digital videos

• Computer software

Computer software

• Computer models

Computer models

• Blogs

Blogs

• Other personal websites

Other personal websites

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Stimulus Stimulus

• “

“Predicting the Life Expectancy of Modern Predicting the Life Expectancy of Modern Tape and Optical Media Tape and Optical Media” ”

( (Vivek Vivek Navale Navale, National Archives and Records , National Archives and Records Administration; Aug 15, 2005, Administration; Aug 15, 2005, Vol Vol 9, #4) 9, #4) “ “[The study] shows the probability of failure as a [The study] shows the probability of failure as a function of time at 25 function of time at 25° °C and 50% RH. It predicts a C and 50% RH. It predicts a mean life time of mean life time of 1592 years 1592 years for CD for CD-

• ROMS

ROMS stored under those conditions. stored under those conditions.” ”

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• Recording technologies

Recording technologies

• Comparison of CD, DVD, BRD

Comparison of CD, DVD, BRD

• Stamped

Stamped

• ROM (writeable)

ROM (writeable) – – dye dye-

• based

based

• R/W (re

R/W (re-

• writeable)

writeable) – – phase phase-

• change

change

• R/W (re

R/W (re-

• writeable)

writeable) – – magneto magneto-

• optical
• ptical

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Technology Migration

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SEM of Stamped CD

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SEM of CD-R

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Confocal image of CD-R

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Recordable Optical Discs

• Works primarily through the use of

cyanine dyes that absorb energy and create a pit-like structures that act as Amplitude Gratings.

• Use Groove tracking for “Writing”
• function. Pit-like Gratings for the

“Reading” function.

Courtesy of Mark Worthington

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REWRITABLE OPTICAL DISCS

• RW technologies use phase

change materials. Active layer (metallic stack) changes states when exposed to pulsed low energy level. Returns to reflective state when exposed to higher energy level. (crystal/amorphous)

Courtesy of Mark Worthington

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Magneto Magneto-

• Optical Technology

Optical Technology

• Based on Curie point of magnetic materials

Based on Curie point of magnetic materials

• Uses:

Uses:

• Laser to heat material to near Curie point

Laser to heat material to near Curie point

• Magnetic field to change magnetization

Magnetic field to change magnetization

• Kerr effect in read

Kerr effect in read-

• back

back

• Features:

Features:

• Magnetic domain as small as spot size of laser

Magnetic domain as small as spot size of laser

• Nearly infinite R/W cycles

Nearly infinite R/W cycles

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Research Progress to Date Research Progress to Date

• Research on stability and adhesion of metal

Research on stability and adhesion of metal films films

• Tape test for adhesion

Tape test for adhesion

• Boil test for stability

Boil test for stability

• Research on size and optical properties of

Research on size and optical properties of recorded bits recorded bits

• Protective layer for recording

Protective layer for recording

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Recording Recording

• Excellent optical contrast
• Consistent spot characteristics
• Can easily be made into the size necessary
• Estimated lifetime of at least 1,000 years
• Can be readily reduced to practice

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Conclusion Conclusion

• The problem is real
• The need is great
• Existing archival options are inadequate
• Solutions exist using familiar materials and

processes