On 2 Dec 2005 at 0:32, Toralf Lund wrote: > Tapes are the most commonly used media for backups on large computer > systems. They have a longer expected shelf lifetime than anything else.
In other words a back-up solution not quite equivalent to the cost of DVD burner and 100 quality DVD media. The shelf lifetime for tapes (or any other magnetic media) is likely more limited than read only optical media. The magnetized tape loses it's magnetization over time and oxide binders fail, I've had a lot to do with digital and analogue tape media in the past. > I haven't seen it myself, either. But some of the people who use CDs for > professional archival will renew them (as in copying the data to new > medium) every 5 years. Apparently, they are most concerned about media > separation, i.e. that the disc literally falls apart. DVD media is a constructed as sealed polycarbonate sandwich, they should not suffer the potential effects on the data layer that may effect CDs if a poor/faulty lacquer was used. I've seen CDs (only mass pressed music discs) that showed signs of corrosion coming in from the edges but I've never seen a delaminated CD and I never expect to see a delaminated single later DVD-R. > What I have seen, are CDs that just can't be read after they were > written (not a big issue except you loose a CD), ones that seem OK, but > have data inconsistency at some point, and also (this is the really > dangerous one) ones that seem all right, but will only work with certain > readers. The situation was probably a lot worse than it is today a few > years ago, though, when CD writers were young and inexperienced, to put > it that way... I've still got discs written on the earliest Philips CD-R burners and they are absolutely fine. What I do when I write my DVD back-ups is write/verify in one unit then transfer to another drive where I let Thumbsplus index the disc, so I have always read the entire disc twice in two readers. > Possibly cheaper, but not costing nothing (far from it). (And you do get > cheap "package" options for film, where the prints definitely don't cost > more than the ones from digital.) Sure they are out there but for large print it's never been less expensive (in Oz) Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
