re preservation of info on mag media, fwd

[Richard Boyden <richard.boyden@sanbruno.nara.gov>]

Whoops, There Goes Another CD-ROM: Storing Information on
Disk and Tape Is Convenient, but How Long Will it Last?
By Laura Tangley
US News & World Report 
February 16, 1998

The parchment has yellowed and the ink is badly faded, but with a bit of
effort one can still make out the words of the Declaration of
Independence and the Constitution, penned more than two centuries ago.
Both are painstakingly preserved by the National Archives in
Washington, D.C., not merely as historic curiosities but, in the words of
an official sign, as testimony "to the accountability of a government that
lays itself open, through its records, to the scrutiny of present and
future generations."

Future generations will be fortunate, however, if they get a chance to
view the records of the current Congress, or to look at some 8 million
presidential files due to arrive at the National Archives soon after
President Clinton leaves office. Most of the documents will be in the
form of computer disks, CD-ROMs, and magnetic tapes. And these
modern record keepers, archivists and librarians warn, are turning out to
be far less durable in many cases than simple parchment.

Tests by the National Media Lab show that top-quality VHS tapes stored
at room temperature preserve data dependably for just a decade.
Average-quality CD-ROMs become unreliable--some can be read, some
can't--after five years. And even when tapes and disks remain intact,
the hardware and software needed to read them may no longer be
available.

This is a formidable threat, considering that by the year 2000 about
three quarters of all federal transactions will take place
electronically. Records pertaining to health and human survival--studies
of disease transmission, for example, or the location of toxic-waste
sites--are of particular concern. The danger extends to the nation's
cultural legacy: Virtually all new music, animated art, and early drafts
of literature and academic works are created and stored in computers. If
such accomplishments are lost, says Deanna Marcum, president of the
Council on Library and Information Resources, "we leave an incomplete
legacy to future generations."

Part of the problem is that tapes and disks, unlike paper, often do not
show degradation until it's too late. Occasionally tapes become so
brittle that the magnetic coating actually separates from its backing.More
often, however, the signs of damage are subtle: Routine exposure to
everyday magnetic fields will rearrange some of the tape's magnetized
iron particles. When a machine plays the degraded tapes, these
alterations make the tapes unreadable, resulting in missing data. A few
years ago, for example, scientists from NASA's Jet Propulsion
Laboratory tried to read some of the magnetic tapes that contained the
results of the 1976 Viking mission to Mars--tapes that had been carefully
stored and appeared to be in good shape. Noting that 10 to 20 percent of
them had missing data, one frustrated researcher called the
decomposing tapes "a disaster."

Even more troubling than the fragility of storage media, however, is how
rapidly computer hardware and software become obsolete. Unlike paper
documents and traditional audio and video recordings--which as analog
media present a continuous, start-to-finish record of
information--computers store data digitally. By breaking information
into electronic or magnetic strings of 1s and 0s, digital technology has
made it possible to store and access enormous volumes of data using
very little space. But without the programs and equipment used to
encode it, digital information makes no sense.

Time bomb. Any computer user who has tried to find software to
translate WordPerfect 4.0 is already familiar with the problem. In
government and industry, the difficulties are magnified. Dectape and
UNIVAC drives, which for years recorded massive amounts of
government data, have vanished, as have software programs like
FORTRAN II. Often, archivists don't discover that data are inaccessible
until someone requests the information. Donald Waters, director of the
Digital Library Federation, calls the problem a time bomb whose full
impact will register only in the future.

Instances of lost data already have begun to surface. Waters himself
faced the problem a few years ago when, as associate librarian for Yale
University Library, he developed a project to transfer 2,000 books from
microfilm to optical disk. Midway through the project, the software he
was using became obsolete, and the disks no longer could be easily
read. At the New York State Archives, Margaret Hedstrom, now at the
University of Michigan, tried unsuccessfully to read magnetic tapes,
recorded in the 1960s, which mapped land use throughout the state. On
a larger scale, satellite photos of the Brazilian Amazon taken during the
1970s--data critical to establishing deforestation trends both
regionally and globally--are also trapped on indecipherable magnetic
tapes.

There's no quick fix in sight. But Marcum says that librarians
andarchivists must now start thinking about preservation as soon as
new knowledge is generated--deciding what's important to save, putting
the information into as common and standard a format as possible, and
carefully recording what machinery and software were used to encode
the data. This week, the Getty Conservation and Information Institutes
will convene a meeting in Los Angeles to discuss these issues. Some
archivists look to technology as a long-term solution. At Rand, for
example, senior computer scientist Jeff Rothenberg is designing new
kinds of "emulation software," programs that instruct new computers to
behave like older ones so they can decipher obsolete digital data.

Ironically, some of the latest ideas sound more like the past than the
future. Norsam Technologies, for instance, is promoting HD-Rosetta, a
system that "permanently and safely" stores historical documents--but
only if they are converted from digital back to analog data. Another
company, Cobblestone Software, actually uses paper to print out
complex patterns of dots and dashes representing computer files. Called
PaperDisk, the product is designed to resist the damage that heat, cold,
and magnetism inflict on magnetic and optical media. The company says
its invention should last for hundreds of years: about as long as
old-fashioned, top-quality paper.
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