[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

More information on the CD eating Fungi plus DVD Laser Rot.



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

Have a look at Deterioration in Dual-Layer DVDs at http://www.mindspring.com/~yerington/

Another article from the following www site at http://www.banjo.com/Articles/021096.htm

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