Archival Media

I’ve always wanted to write about this as I’ve noticed that few people have encountered the phenomenon before. The topic has to do with the choice of archival media for long term storage. With the amounts of data that we generate today, whether it be videos, images or text, we need some form of method to store the data safely. This applies as much to research and work as well as personal data.

A very common way of archiving data today, is the blank CD or DVD. It’s cheap to obtain, small enough to not take up much space, and holds a large amount of data on it. Many people are under the impression that it is safe and reliable. I’ve always known that the chemicals used for the burning layer, have a lifespan. Some research would reveal the manufacturer’s quoted lifespan as about 75 years or so. More than sufficient for personal data.

But something happened to me once, to change that perception. It all happened quite by accident.

I was working on my computer at home, one lonely afternoon. As the day was quite hot, I bought myself a big packet of cendol, which is a popular Malaysian beverage, which is made of crushed ice, gula melaka – a form of brown sugar made from coconut, red beans and some green gelatinous thing made of starch. So, it’s sweet and cool, perfect for a hot sunny day.

I poured the beverage into a big 12cm zebra brand steel mug, which should be fairly familiar to any Malaysian, and sat it down on a coaster. The coaster was basically a spent CD-R that didn’t quite burn properly. As they were usually termed as coasters, I used them literally as such. This was when I noticed something interesting. A ring of clear plastic would appear under the base of the big steel mug. It would seem that the CD-R coating had dissolved in the water that condensed on the outside of the mug and collected at the bottom.

So, I did a few more experiments, and ran the CD-R under tap. I even drowned it in a basin of water. However, the chemical layer only dissolves under the steel mug of cendol. So, I bought a few more mugs of it, over the next few days and ended up with a crystal clear piece of CD-R plastic. The entire top layer had dissolved off, including the metalic coating.

It would seem, that the chemicals used are actually water soluble, under the correct temperature conditions. I have no idea what the threshold temperature was, but it is definitely above freezing. So, it may not be a good idea to put archived data into “cold storage”, so to speak.