On 2018-12-05, deloptes <delop...@gmail.com> wrote: > Thomas Schmitt wrote: > >> To my experience, degradation of once verified media is rare, even long >> after they have been written. More probable is drive degradation. >> (With re-usable media stored for a long time, there is an increased >> probability that they fail to take new data. But that's a different >> problem.) > > I always "verify" after burning a disk, but the nature of the CD/DVD implies > degradation of material. The speed (and lense power) influence the quality > of the writing, of course also the materials used and their quality play > role. But still a disk is very unreliable medium for data storage over long > period of time IMO. > > regards >
Here's a decade-old (and a little more) opinion from UNESCO (?) about the matter (although they completely ignore the critical 'shape' parameter mentioned by TS): While recordable optical discs are viable tools in the access to and dissemination of digital information of all kinds, it is strongly recommended that professional data storage methods, as developed by the IT industry, should be used. All digital carriers are to some extent unreliable, however, data tape and hard disc systems are made reliable because technological testing, copying and management systems are implemented to support the data carrier and the quality of its content, maintain and manage the integrity of the data. These systems are feasible for storing critical data even under climatically and financially sub-optimal conditions. No viable automatic testing and management system exists to make optical disc reliable, and consequently any archival use of optical systems must depend on a manual approach using people and testing equipment as described in this publication. http://unesdoc.unesco.org/images/0014/001477/147782E.pdf
