Can you elaborate on the lack of reliability you are referring to? E.g. are you saying the data is incorrectly written to begin with, or that the media degrades over time and can't be trusted later on or something else?
DVD's are exposed to the human element (scratched, etc). Hard drives are really much more reliable. I have used Drive Image for 4 years without a problem.
I have a friend who wrote hundreds of CD's in the past years with his Mac. Last year he wanted to replace the CD's by a HD. About 40% of his CD's were degraded so much that he couldn't copy them anymore to the HD. He also made copies of original software he bought. Apparently these copies had the same problem, but the original CD's not. It looks as there is a difference in quality of writing between the CD's you write at home and the CD's produced by software developers. I make backups on an almost daily base for several years now. I never had any problems with reading or putting back images. I use Acronis and only backup on HD. I even tested brandnew systems that came right out of the factory and installed disc images that were made from other systems without any problem and functioning for 100%. We replace about 2000 computers a year in our company, and the software is always installed from 1 disc image. Never had any real problems.
Hmmm, I've never had that kind of bad luck with even the cheapest CDR's degrading (perhaps they are being stored badly?) but I do know they make CDR's specifically designed not to degrade overtime (search for Archival CDR) Never bothered to buy them myself. Yep, they are made completely differently so that would be expected. I dunno, never really researched it but I would think that a mechanical device like a HD would tend to have more reliability problems over time as compared to a burned DVD, placed in a plastic case and stored in a safe place. Don't see any reason that a human would be handling the backup except in the case they need it to restore. How scratched could it become?
http://www.usatoday.com/tech/news/2004-05-05-disc-rot_x.htm Two persons who are known in the IT sector as experts wrote the following article: At Siemens someone did a test on CDâs. All CDâs were stored standing upright in Case Logic maps. They were hardly used. The results of a test with Kprobe were frightening. 75% of the CDâs had C2 errors. There are three error levels. C1 appears on almost every CD. These minor errors are transferred to the C2 error decoder. C2 errors are transferred to the ECC (error correction code)-decoder, or with music CDâs interpolated. If ECC fails the CD is no longer readable. C2 errors should never appear on good CDâs. But on 75% of the archived CDâs they did appear. ALL CDâs that were older than 3 months had C2 errors. CDâs came from Fuji, Philips, Silver Disc and Sony. If you archive on CDâs only use CD-R NEVER CD-RW. The best speed to use is the lowest speed mentioned on the CD, because CDâs are optimised for that speed. Donât think that DVD is the ultimate solution, because tests showed that they are even worse.
All factors may be involved. Ruling out poorly working DVD writers and poor DVD discs, the remaining problem is medium degradation. Storage is of utmost importance: humidity, temperature, light. Google around a bit, you will easily find all these discussed. Spike500's reference is a good starter: http://www.usatoday.com/tech/news/2...-disc-rot_x.htm As others have also observed in this thread, it is not at all unusual to come at once accross a defective disc still working correctly a few days before.
Let me still add to the above that "factory pressed" CD's and DVD's are doing much better stability-wise than the home-written discs, this due a much more delicate bit formatiom process in the disc layer. In fact the time of storage BEFORE writing likely will also play a role in degradation.
Maybe it's my previous life in IT, but I am very paranoid. I can't tell you how many times I had to releech my MP3 collection back in the day. From my experience the best way to do backup is not to focus on one fix exclusively. Back it up on CD & DVD, use RAID, use some external or just internal cased or just another seperate HD. Also look into setting up a simple image, this can get you back and operational quickly, if doomsday appears. The standard fix in the IT world is no longer to fix anything, just to simply reimage it. I am telling you I have seen things fail for no concievable or exlplainable reason. Computers can exhibit the oddest behavior. CDs & DVDs CAN degrade. So don't bet the farm on them. Implement a strategy of MASS backup. Raid/Media/Seperate HDs. With a proper setup (raid in this case), if a HD fails, you should experience very little downtime and no loss of information. You should be able to simply pull out the bad HD, replace it with another one and be good to go. So in summary. Pick up a good RAID card. Example - http://www.newegg.com/Product/Product.asp?Item=N82E16816103004 After your done setting all that up, you can breath a little easier. I would also then do some dvd or cd burning, and depending on what it is, uploading it to a file server somewhere. The key is to not believe in one source. Trust me PCs and related components will do strange illogical, and unexplainable things. So it's best to cover your bases
The best, simplest, cheapest solution is 2 new internal SATA drives... Plus one external USB 2.0 drive like the Vantec NexStar3. Your motherboard must support SATA... IDE is 2-3 years out-dated... And you may not be able to boot via a SATA PCI adaptor. Use Casper XP every 2 days or so... And you will have 3 exact, bootable clones (2 internal, 1 external). You are using Drive C: 99% of the time. If Drive C: dies or is corrupted... Just open up the box and switch SATA cables between dead drive and clone... And you are up and running in minutes. There is nothing more complicated or dangerous than a proprietary RAID NAS. The product is designed for salesmen to extract money from you. These products change constantly. It's all about the sexy sales pitch. If your super sexy RAID box develops a serious problem... Good luck to you... Hope you are a hardware and software engineer. Start packing the box and ship it back to Timbuktu. Hope they speak English.
Opening up the box and switching cables is a pain. On my next box, I plan to have two removable drive cases. This way I can switch drives to my hearts content and not have to switch cables. Imho this is the way to go. Anyone have any thoughts or suggestions? tia nt