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DVDisaster is an awesome tool for archiving things reliably, as it creates ECC in case of physical damage to the media. However, when using it for backup purposes it can be a bit awkward -- one must create ISO images of whatever one wants put on a disk, then run them through DVDisaster, then burn the augmented image.
Does software exist which can do this without creating a temporary ISO image first? (It's extremely slow....)
Billy ONeal
Posted 2011-10-28T18:05:46.487
Reputation: 7 021
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I haven't seen any other software that implements DVDisaster's algorithms.
That said, if you're using the RS02 version to augment the ISO with ECC data, how do you propose to process an ISO that doesn't yet exist? The entire process hinges on having an existing ISO to modify. DVDisaster could implement basic authoring capabilities to allow it to build augmented ISOs directly, but it'd still be slow -- calculating all the ECC data simply takes time. They'd also still need to be able to process already created ISOs simply because I doubt they're interested in implementing all the various bells and whistles that high-end authoring programs have.
Either way, it's still very desirable to have a complete ISO created first. Relying on buffer underrun protection to ensure that you have a usable disc doesn't strike me as the safest of ideas for a program designed to protect your data.
afrazier
Posted 2011-10-28T18:05:46.487
Reputation: 21 316
The ISO could be "virtual", so to speak, as it's done in other on-the-fly CD burning apps. As for buffer underrun, creating the ISO doesn't solve that problem. – Billy ONeal – 2011-10-29T03:38:36.607
The problem with that is that if your files are modified at all between calculation and burning, your ECC data is invalid at best and may end up producing an invalid ISO depending on the augmentation process. – afrazier – 2011-11-01T16:22:52.870
@afazier: Well, that's true for any app that doesn't create an intermediate ISO. Hell, even if you do create the intermediate ISO nobody says the file copy you made was a consistent copy. – Billy ONeal – 2011-11-01T16:36:08.140
It's trivial if the file is opened with the appropriate access flags. Even in the cases where it isn't, the data inside the intermediate ISO can't be changed out from under dvdisaster and is thus for the purposes of ISO authoring and ECC augmenting. Allowing windows for the underlying data to be changed between authoring, ECC augmenting, and burning is what's dangerous. – afrazier – 2011-11-01T16:51:42.540
You're assuming the underlying OS supports such access flags. POSIX, for instance, doesn't allow file locking. As for Windows, the hypothetical tool could hold open handles to the files in question open in exclusive mode. – Billy ONeal – 2011-11-01T17:13:35.427
That just makes getting an immutable view of the data (consistent or not) even more important. – afrazier – 2011-11-01T18:08:57.013
There is no such thing as immutable data on the filesystem. – Billy ONeal – 2011-11-01T19:01:19.450
It's effectively immutable if you make a private copy, which is the point of creating the intermediate ISO. – afrazier – 2011-11-01T19:09:04.130
I don't see how that's true. – Billy ONeal – 2011-11-01T20:14:13.063