There seems to be a broad consensus that magneto-optical disks offer
the most reliable long term storage for data. Here is something that
appears to be similar, and holds 30GB in a 5 inch package!

What do you think about this medium?

http://www.akibalive.com/archives/000487.html

Reproduced below:

Mitsubishi Chemical Media Corporation (Japan) has announced the
development of a 5 inch optical UDO (Ultra Density Optical) disk
capable of 30GB of storage. The optical disk will go on sale during
the fall of 2004.

UDO was invented by a British company called Plasmon, and utilizes a
blue laser to read and store data on the disks. Mitsubishi received
licensing from Plasmon to sell the disks. Developers such as Plasmon
and HP will start developing drives to read and write the disks.

The UDO media is an ideal format for enterprise storage systems and is
10,000 times more reliable than current storage types on the market.
The expected price for one disk is around ¥10,000 ~ ¥20,000.
--
David Arnstein Please do not look at laser with remaining eye