Optical Storage is the most permanent form of commercial storage available. Optical storage are discs like standard CD and DVD and Blu-Ray discs which can be marked in patterns that are then read by focused laser light. Most of these are considered to last longer than magnetic storage but are still not permanent. A CD can hold 700 MB of data a DVD 4.5 GB . A Blu-Ray DVD holds 25 GB, 50 GB or 100 GB. Standard optical media are susceptible to UV Light and damage from temperature and mishandling. The dye layer used to write the information on decays over a few years’ and is considered usable for 8 to 10 years.
There is a relatively new type of optical storage disc out now made by Millenniata called Mdisc that claim a 1,000 years of permanence. Mdiscs use a rock like material instead dyes to record the patterns on the disc physically marking the disc with the information. These discs are more expensive than standard discs but even if they only last 100 years, the extra price would be worth it. Mdiscs need a compatible machine to use them; they cannot record but will play in a standard machine. Larger companies now offer such machines and compatibility. Mdiscs come as standard DVD’s that hold 4.7 GB per disc and Blu-Ray DVD’s that hold 25 GB per disc.
All storage has their drawbacks and physical limitations. Ultimately it is up to each individual to decide what's right for their working conditions and budget. I hope these brief posts gave people ideas for their own solutions.