Ronda, When I first started to back up to CDs, and then DVDs as they became available, I used the cheapest blanks I could find, not realising that not all optical media are created equal. However, I did always burn at the slowest speed recommended by Toast.
Since then I have become a bit more savvy and now use Taiyo Yuden DVDs for important backups, but still at the lowest recommended burning speeds. Because of what I have learnt I verify all of my important oldest items, some up to 14 years old, every now and again. Luckily, I have not yet had a single failure in either the offsite or onsite copies; even those burnt on the cheapest of media. You may be interested to know that I store the disks in 100 disk spindles, which is not the recommended but more expensive way. However, I store them in a light-proof cupboard here, and in a light-proof box in the offsite cellar. I also store my blank media in the lightproof cupboard. Just to be doubly safe, I am slowly copying important files older than 10 years, and those with obsolete file formats, to new Taiyo Yuden DVDs, updating the file formats as I do so. The AppleWorks files I asked for help for a few days ago aren't from my backups, thus the updating problem. Much of the material on my earliest optical backups came from the roughly 500 floppies, and several SyQuest disks, that I used for backup before optical media became an affordable option. From my backup experiences over the years I suspect that in the long run obsolete file and media formats will be a bigger backup problem than media breakdown. Decadic renewal must become part of any decent backup program. As file formats, and media formats change over the years users must keep a careful watch on keeping their data formats and media formats up-to-date. My index of backups tells me that I even have MacOS 1 (Finder 1 & System 1), Microsoft Word version 1 and PageMaker version 1 on some of my older CDs. I can't think of a reason to continue curating such items so will let them reside on the old CDs till they physically perish. On 22/03/2011, at 4:07 PM, Ronda Brown wrote: > 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) Regards, Ray Forma 50 Harvest Road, North Fremantle WA 6159, Australia Tel +61 (0)8 9335 6568 Mob +61 (0) 428 596938 -- 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]>
