Kent Wang
16th July 2003, 15:26
I just got my burner a few days ago and have been having great fun backing up my DVD's to DVD+R. However, burned DVD's tend to have a tendency of failing after a few years so this is not really a great solution. I do want totally lossless backups so just keeping Xvid encodes on my hard drive doesn't cut it for me and keeping DVD image backups would be too huge.
The solution that I've found is to use a tool called parchive (http://parchive.sourceforge.net/). It creates a parity file that can be used to recover any damaged sectors. On a DVD-5, there is usually about 400MB of free space so I just fill in the rest with parchive parity data. This will give you around 6% redundancy, meaning 6% of the disc can be damaged and all your data will still remain intact. Since most discs tend to just have one or two damaged sectors (with age, not rough handling), if you check your discs once a year you should never lose any data. When splitting a DVD-9 across two discs, I've often found that each disc will have enough free space to accomodate 30% redundancy. Even better!
I do believe that you can add the PAR files to a DVD and still have it playable in a standalone. I've never tried since I don't have one, but it makes sense.
In conclusion, I think everyone should use parchive when backing up anything to a damageable medium, like CD's and DVD's especially when you'll always have some extra space left on a disc to fill with parity data. This is already a well-known tool over at Hydrogen Audio and some of the Matroska developers have been discussing the concepts behind parchive here.
The solution that I've found is to use a tool called parchive (http://parchive.sourceforge.net/). It creates a parity file that can be used to recover any damaged sectors. On a DVD-5, there is usually about 400MB of free space so I just fill in the rest with parchive parity data. This will give you around 6% redundancy, meaning 6% of the disc can be damaged and all your data will still remain intact. Since most discs tend to just have one or two damaged sectors (with age, not rough handling), if you check your discs once a year you should never lose any data. When splitting a DVD-9 across two discs, I've often found that each disc will have enough free space to accomodate 30% redundancy. Even better!
I do believe that you can add the PAR files to a DVD and still have it playable in a standalone. I've never tried since I don't have one, but it makes sense.
In conclusion, I think everyone should use parchive when backing up anything to a damageable medium, like CD's and DVD's especially when you'll always have some extra space left on a disc to fill with parity data. This is already a well-known tool over at Hydrogen Audio and some of the Matroska developers have been discussing the concepts behind parchive here.