Dear,
Colleagues
I have
now located additional data on the CD eating Fungi plus information of CD &
DVD Laser Rot.
All is
not lost. If we live in low temperatures and low humidity our CD’s are safe.
Watch out for human habitable environments e.g. air conditioned human
habitable.
For
those with large CD collections I hear that Real Estate prices at the South
Pole are soaring!
We have
known for some time that microfilm at 8-12 degrees Celsius and 30-40%
relative humidity is less affected by deterioration due to the low temperature and also
low plus the absence of ambient light mainly ultraviolet light [the darker the
better]. With microfilm for preservation purposes we have three copies, 1. the
original camera master, 2 a duplicate working master [from which working copies
are made] and, 3. the working copy. Wen the working copy deteriorates, gets
scratched etc we create a new working copy form the working master. The
original camera master is seldom if ever used again and thus is safe in its low
temperature, low humidity and dark surroundings. We need to treat CD’s with the
same respect. Once long –term or mission critical information is written to CD
we need to lock our master copy away at low temperatures 8-12 degrees Celsius and 30-40%
relative humidity then follow the microfilm patter of having three copies. This is
assuming that once we defrost the media that we have CD readers and writers
available to be able to read and duplicate the media we have stored.
Locally
it was proposed that a CD be deposited in a time capsule to be opened in 100
years from now so that the next generation would be able to evaluate the events
of the previous Australian Centenary Year of 2001. On seeing the documentation
I expressed my concern in respect to the procedure proposed. My understanding
is that the project did not proceed.
This
next article is similar to the previous article posted on the 25-Oct-2001 and
along with the second article in this post probably explains the situation
best. It would appear that this situation of fungal attach has been known for
at least two years.
12 June
2001
Spores bore holes in compact disks, rendering them useless.
XAVIER BOSCH
Computers get viruses. Code gets bugs. Now CDs get
fungus. Researchers in Spain have discovered a fungus that eats holes in
compact discs, corrupting the information stored in them.
After visiting Belize in Central America, Victor
Cardenes of Madrid's National Museum of Natural Sciences (MNCN), found one of
his CDs discoloured, transparent and unreadable.
The disk's aluminium and polycarbonate layers were
riddled with fungus, Cardenes and his colleagues have discovered.
The team has isolated and cultured what they believe
to be Geotrichum candidum. Usually, this fungus lives on plants and animals.
Occasionally it infects the human respiratory tract. DNA analysis is pending.
Burrowing in like worms from the side of the disk,
"the fungus destroyed crucial information
Some fungi are known to live on plastics and
polymers, but this is the first report of a CD being eaten by a fungus. The
researchers believe that the spores probably entered the CD in Belize.
The rarity of this phenomenon suggests that Belize's
high temperatures and tropical humidity were crucial. To find out more, the
Spanish group has posted an offer on the internet to analyse unreadable CDs
from anyone wanting to test their disks for fungal infection. They have also
submitted their work to the journal Natur Wissenschaften.
The problem with fungi is that we know far less
about them than about bacteria, explains environmental microbiologist Marc
Valls of Madrid's National Center. The finding that one has a taste for CDs is
"not very surprising" he says, but it offers hope that fungi with
similarly unusual proclivities might be exploited for environmental clean-up.
© Nature News Service / Macmillan Magazines Ltd 2001
Plus
another article:
Thursday July
26, 2001 6:30 pm Eastern Time
OUTSIDE THE BOX:
Sci-Fi Becomes Reality—The Metal-Eating Fungus, Shelley Souza,
Optionetics.com
An engineering friend sent me a copy of a news list whose members are
interested in risks to those who use computers and related systems. The first
story, which is now a couple of months old, was something right out of Arthur
C. Clarke’s Rama books: a CD-eating
fungus. Koninklijke Philips Electronics N.V. (PHG)—the Dutch electronics
company that invented compact discs—believed the problem was a freak case
caused by some extreme weather conditions in Belize, in Central America, where
it was first detected. I wanted to find out if that was true, so I decided to
do a little more research. (As an aside, someone introduced me to Copernic, a
company that offers meta search engines, among other types of data retrieval
tools. It is undoubtedly the best search engine I have ever used. Investors
might want to test out their free version for fundamental research.)
Basically, our fungal friends from the Rama
spaceship eat holes in CDs. Dr. Victor Cardenes learned of the microscopic
creature two years ago when he was visiting friends in Belize. They complained
that some of their CDs were unplayable; on closer inspection, Dr. Cardenes and
his colleagues at the Superior Council for Scientific Research in Madrid
discovered the fungus was eating through the aluminium layer. The Electronic Telegraph, a British news
site, reported in June that the fungus had "burrowed into the CD from the
outer edge, then devoured the thin aluminium layer and some of the data-storing
polycarbonate resin.” Dr. Cardenes said, “It completely destroys the aluminium.
It leaves nothing behind.” While the Spanish scientists had never seen this
variety of fungus, they concluded it belongs to a common genus called the
Geotrichum candidum. This particular fungus can occasionally enter the human
respiratory tract.
The BBC said Javier Garcia-Guinea, head of Geology at the Museum of Natural
History, said it was not unusual for fungi to attack plastic, but this was the
first documented case of a fungus attacking CDs (eating metal). He said the
museum had received many e-mails this year from other countries in Central
America describing similar cases. Marc Valls, a Spanish biologist from the
National Centre for Biotechnology, told the BBC that there was "...no need
for alarm. Although the fungus was widespread, it would only attack CDs exposed
to high humidity and high temperature, which is not the case most of the time.”
Nonetheless, for security and archiving experts, the existence of a CD-eating
fungus poses a new challenge just when these groups thought they had solved the
problem of risk-free permanent storage. Mr. Valls commented that Nature is
exceedingly clever in figuring out ways to eventually reduce everything to
biodegradable status. And another report said that understanding the properties
of this strain of fungus could lead to some breakthroughs in environmental
waste management.
So, as weird as this story appears on the surface (no pun intended), from a
technological view, it could be the beginning of a new way to tackle the as yet
insurmountable problem of toxic waste, along with finding a way to protect CDs
in tropical climates.
Shelley Souza
Senior Writer & Trading Strategist
Optionetics.com ~ Your Options Education Site
Visit Shelley Souza’s Forum
In addition to CD fungi
we also have DVD rot which also applies in a different way to CD’s.
Can DVDs have laser rot?
Laserdiscs are subject to what's commonly called laser rot: the
deterioration of the aluminum layer due to oxidation or other chemical change.
This often results from the use of insufficiently pure aluminum during
replication, but can be exacerbated by sheer mechanical stress due to bending,
warping or thermal cycles (the large size of laserdiscs makes them flexible, so
that movement along the bond between layers can break the seal). Deterioration
of the data layer can be caused by chemical contaminants or gasses in the glue,
or by moisture that penetrates the acrylic substrates.
Like laserdiscs, DVDs are made of two platters glued together, but DVDs are
more rigid and use newer adhesives. DVDs are molded from polycarbonate, which
absorbs about ten times less moisture than the slightly hygroscopic acrylic
(PMMA) used for laserdiscs.
It's too early to know for sure, but DVDs will probably have few laser rot problems.
There have been reports of a few discs going bad, possibly due to poor
adhesive, chemical reactions, or oxidation of the aluminum layer. See
http://www.mindspring.com/~yerington
Laser Rot
If the disc suffers from "laser rot", you should demand from the manufacturer a
replacement disk. "laser rot" is rare on CDs but is common on older
Laser Discs. Laser rot is the
result of "out gassing" from the vinyl to the aluminum which results
in excessive oxidation of the aluminum media material. It is visible and is
definitely a manufacturer defect due to a flaw in their processing.
"Nature is
very clever and, for all the materials that we design, sooner or later they
will be degraded by some organism."
Looking on the bright side: The problem with fungi is that we
know far less about them than about bacteria, explains environmental
microbiologist Marc Valls of Madrid's National Center. The finding that one has
a taste for CDs is "not very
surprising" he says, but it offers hope that fungi with
similarly unusual proclivities might be
exploited for environmental clean-up.
A little bit of
humour on laser rot at http://www.starlaser.com/laserrot.htm
This is not the end of life for
digital and analogue data preservation, as I believe that we may have a
solution in the HD-Rosetta Disk. For further information go to the following
www site at http://www.norsam.com/hdrosetta.htm
HD-Rosetta
Data Preservation Services
Norsam's High Density Rosetta (HD-Rosetta) provides analog storage of
information and images on nickel plates that last for thousands of years. HD-Rosetta
is patented worldwide by Norsam under exclusive license from Los Alamos
National Laboratory.
A query?
What if there
is a nickel eating fungi out there someplace waiting for the HD-Rosetta nickel
disk to be produced in numbers so that they will enter the their food chain?
ONLY JOKING!
I trust that you find the above information of interest and
of value.
Regards, Laurie
Mr Daniel
Lawrance [Laurie] Varendorff, ARMA
Consultant/Trainer/Tutor/Presenter: Records and information Management
Imaging and Micrographic Specialist with 25 years experience
The Varendorff
Consultancy
The Australian
Distributor for A&P International
Scanner & Micrographic Resolution
Test Targets
Visit our www site: http://www.pressenter.com/~apintl/
ABN: 77 836 801
165
27
Ronneby Rd, Lesmurdie, Western Australia 6076 - AUSTRALIA
PHONE:
+61 8 9291 6925 - MOBILE: +61 0417 094 147
EMAIL: Laurie.Varendorff@Bigpond.com