The options are numerous, but only a few should be chosen when it comes to selecting the right system for storing important data safely over long periods of time. Available media includes external hard drives, CDs, DVDs and tape drives. However, there is a little-known alternative: magneto-optical (MO) systems, which owe long-term archiving capabilities to the high magnetic integrity of their media.

Unlike purely optical technologies, magneto-optical systems can be rewritten any number of times. What's more, the media are well protected in their plastic cartridges so that physical damage to the surface practically never occurs - if handled correctly, that is.

The basic principles of MO technology are straightforward enough. First, the media surface is initially insensitive to magnetic forces. To enable polarization similar to that of a hard drive, the surface is heated precisely by laser. It loses its ferromagnetism when what is called the Curie point is reached. While it cools, the MO drive's write heads remagnetize the surface.

But all this comes at a price - MO drives are much slower than CD/DVD drives or even fixed disks. For this reason, the technology has never made it to the end user market and is still referred to as a niche product.

Last fall , we took a look at two different Fujitsu MO drives: the DynaMO 640 Pocket and the DynaMO 2300 U2. The former is a mobile solution for secure data transport and archiving and the latter is for medium-sized data storage that must remain available for many years. The drive we review here is a combination of both, with 1.3 GB storage capacity and mobility features.