Hi Ray, My last post for today to WAMUG, must get other computer work done ;-)
On 22/03/2011, at 2:16 PM, Ray Forma wrote: > I still back up my important files to DVD fairly regularly and make sure > that one copy of the DVDs goes offsite to a friend's cellar in another > suburb. Over the last 15 years I have generated about 500 CDs and DVDs that > now reside in that cellar. I also have copies here in the cupboard. The life-span of a burnable CD or DVD is highly dependent upon the quality of the organic dye it uses. Not all organic dyes are the same. In fact, organic dyes will vary from one product line to another from the same manufacturer. Pressed media have a longer lifespan because the reflective layer is aluminum, which doesn't degrade as rapidly as the organic dyes used for a writable DVD. That having been said, good media such as Taiyo Yuden that's burned with a decently low error rate and stored in a cool dry location should last decades. But you'll never know if the burn is good unless you scan the disc to see what the actual error rates are - you need a burner and software capable of reporting raw error rates for this. It's important to check this because burn quality depends on a lot of factors and a bad burn really can degrade in quite a short period of time. The reality is that ANY media can go bad. The secret to keeping precious files is to (a) have at least two copies, and (b) regularly check both copies to ensure they're readable. If a Disc goes bad, this lets you recover the file from the other copy before it goes bad too. Also, to improve disc longevity, store CDs and DVD's in jewel cases, on edge, in a dark and temperature controlled space. For those of us old enough to remember, these are the same instructions we followed for storing vinyl records. For this reason I dislike DVD as an archival medium since checking that you can still read all of your files means a lot of disk shuffling. It's a lot easier if you use hard drives - you just connect the drive and let it sit there overnight reading files. > > I should really get a fourth drive and use it as a time-machine backup drive. Yes ;-) Cheers, Ronni 17" MacBook Pro Intel Core i7 2.66GHz / 8GB / 1067 MHz DDR3 / 500GB Serial ATA Drive @ 7200rpm OS X 10.6.6 Snow Leopard Windows 7 Ultimate (under sufferance) -- The WA Macintosh User Group Mailing List -- Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> Unsubscribe - <mailto:[email protected]>
