Originally Posted by
sbm12
The optical media is generally very reliable in a static sense. That is to say that as long as you don't need to access it the data is as reliable as most other means. The amount of time for the dye layer to degrade should be long enough that you will have upgraded the backup technology to a newer one by then.
This is not true. There have been many reports of discs becoming unreadable over the course of a few years and, in some cases, a few months. The lifetime of media will depend greatly on the quality of the media, how good the original burn was, and what conditions it's stored under. If you store your DVDs in direct sunlight My recollection is that LTO reads 2 generations back and writes one generation back. So LTO1 tapes are no good in an LTO4 drive (current model for the past 12-18 months, IIRC). I believe that SDLT is similar. I'm not sure about DDS tapes. Compare that to optical media, where a CD-ROM that you got when they first came out should still be readable today in the most current CD/DVD drive, assuming that the disc isn't damaged or degraded.with large daily temperature differences, they'll last a very short time. If you store a DVD in a temperature controlled, dark environment, chances are they won't go bad.
I agree that tape is likely more reliable than optical, but advents in tape technology seem to happen more frequently than optical drives, with the significant potential for leaving old tape media intact but unreadable due to a lack of compatible hardware.
Actually, tape is also not perfectly reliable. When I was doing a lot of work with video editing, I read that tape media in general should ideally be copied once every year to assure preservation. Again, proper storage techniques greatly increase the lifespan. As for tape incompatibility, you're right, but at the same time, you can easily still get drives that read DDS-1.