Hi, > can anybody please give me some recommendations for long term archiving of > data. > Which brands are known to be usable for this?
Brands are not a reliable guideline, i fear. You can read different manufacturer ids from media of the same brand, just bought a year apart (or just a shop apart). Even Verbatim has gone promiscuous meanwhile. If you successfully checkread the archived media after writing, then you have good chances for a long life of the archive. You should of course re-check during that lifetime. I would store at least two copies at different places and hope that the second copy is still ok when the first one fails its yearly test (or vice versa). The more copies, the more hope. My oldest (outdated) CD-RW backup is from 2003 and still passes the yearly random sample test. (One out of 60 CDs is checkread.) It will be convenient and more fool-proof if you store checksums on the same medium which they shall guard. Actually the optical media all have own checksums and error correction which are used internally by the drive. I had two cases, though, were DVD+RW media returned false data without error indication. So an own MD5 or SHA-1 helps to make clear that the data are still as they should be. One may discuss whether the lower density of CD or the more sophisticated checksums of DVD and BD are to prefer. I would make the proposed copies on media of different manufacturer and/or media type (e.g. DVD-R versus DVD+R). Said this, my youngest BD burner bears a logo "M (swirl) DISC", which means "Millenial Disc". This is DVD+R or BD-R with mineral dye. http://en.wikipedia.org/wiki/M-DISC The web shows positive and negative opinions. One thing is certain: They are more expensive than other media of the same capacity. There are archive formats like RAR, which are prepared for the loss of chunks of archive data. http://en.wikipedia.org/wiki/RAR Optical media are supposed to fail partially first. So there is hope that in the beginning of deterioration, enough redundant intermixed archive parts stay readable. Have a nice day :) Thomas -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: https://lists.debian.org/[email protected]
