Can you suggest improvements and help me work out the details of my plan to back up several hundred GB using the Mac? I just dug a box of CD-Rs from 1998 out of a box - the first CDs I burned just after I got a burner. On them are files going back to when I started using computers, and out of 20 discs or so, only a few files on one disc were corrupted. I wouldn't have been heartbroken if any of these files went missing, but I would if a lot of files I've created since were to disappear, especially because photography has become digital. Additionally, I've recently had several thousand negatives of old family photos scanned.

My data is fairly well backed up across multiple hard drives, but I still feel somewhat vulnerable without having any backup which is not a hard drive. I have several hundred GB of data at this point for which I would like a backup I can toss in a box for 10 years like my CDs from 1998 -- something off-line, permanent, with at least several decades expected realistic lifetime.

My plan:

1. Create a DMG as large as I anticipate the total amount of data to be.

2. Copy everything I'd like to back up to this DMG.

3. Using some sort of standard terminal commands built into OS X which I forget (any help here?), split this huge DMG file into parts sized to fit onto DVDs (haven't decided between single and double layer yet).

4. Using MacPar create parity files sized the same as the regular part files. The advantage of doing this is that I can say "as long as less than 10%, or any percentage I decide, of discs are corrupted when I want to restore my files, I can restore all of my data bit-for-bit." The disadvantage of this is that if too many discs are corrupted, I lose EVERYTHING, as opposed to if I had just put files on discs without enclosing them in an image.

I feel that the tradeoff described in #4 is worth it, considering that it is a royal pain in the ass to manually split up a ton of files onto separate discs.

Another thing that I have thought about is that this scheme relies entirely on formats which are pretty standard, maybe even open source. PAR, DMG, and the unix-based split/join commands (hopefully someone will remind me what these are) will be possible to access for a very, very long time. The weird proprietary format for some random backup program, not so much.

I anticipate that it will take a few hours at once to create the split image files, perhaps overnight or more to create the PARs (but this time is unattended), and then I can burn them over a few days/weeks. Not too bad.

Can anyone comment on this, or suggest an easier/better way to create an optical backup of 200 GB of files or so?