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Field of the invention
There is a need to store large amounts of digital data
for long periods of time in an error-free manner. These data are originally in
digital format or are data that have been digitally scanned from original
content. The data are to be stored as replacement for storage of the original
content, or the data are to be stored in parallel to the storage of theoriginal
content. For instance,
historians
store historical documents and images in archives, and the military, police and
security forces store vast amounts of information such as satellite imagery,
military maps, manuals, war records and iris recognition files. Still other
types of information that are stored in mass are patent records, census records,
geospatial records, images collections, and sound records of music and speeches.
Solutions provided by the invention
To provide the solution for long-term, error-free archival
storage, the dual problems of backward-read compatibility and of the uncertainty
of storage media failure had to be solved. The invention not only provides the
solution to those two problems, it also provides the solution for accessibility
of the archived data files when files are needed for outside reference or for
rebuilding of outside failed on-line search and retrieval systems. The
invention also provides for security of the archived data files to guard against
fire, earthquake and terrorist attack. The invention provides the solution for
archiving all file sizes, from megabytes to zettabytes.
Profile of Morris & Ward
Four years ago our consulting engineering firm had as a client
a digital printing firm. That firm printed posters for the National Gallery of
Art's sales shops. The Gallery asked the firm to solve a data scanning and
storage problem, namely, scan the Gallery's record 8" x 10"
Kodachromes and then store, error-free, for 100 years, the digital record of
each scan.
We solved the scanning-in problem for the firm, specifying
a foreign-made photomultiplier tube ("PMT") drum scanner. Using the
scanner, the Gallery's challenge image, Titian's "Doge," c. 1600, was
digitized, producing a 4 GB file, with 32-bit color depth.
The Gallery
's concept was that firm would produce a digital equivalency to place into the
Gallery's vault along with the Kodachrome and the acid-free paper record of
calibrated Colorimeter readouts of the Kodachome's four RGB color wheels (one
wheel in each corner), the package to come to light again 100 years hence. What
the Gallery wanted was a digital backup in case of the failure of the Kodachrome
colors and/or image.
At that time a digital equivalency could either
be an optical disc, CD or DVD. Because the equipment for writing and reading
DVD's is inexpensive, compact, and ready at hand, we researched the longevity
information available on DVD's. The answer was that there were no accurately
known time frames beyond 5 to 10 years before disintegration would begin to
cause errors.
Also, since we were aiming for 100 years,
another type of problem, namely the "backward-read compatibility"
problem, would arise. Backward-read compatibility problems have arisen, for
example, with reel-to-reel tape, with out-of-date tape cartridges, with the
optical sound tapes from the Nuremberg trial, etc. At 100 years hence, even at
30 years hence, there would be no perfectly working machinery, and, more
likely, no working machinery at all, for reading the storage media.
We
embarked on a program to research and develop technology for solving the
now-identified archival data storage problem. |
