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Old May 26, 2013, 08:27 PM   #1
ScottishCaptain
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Recovering files off a DVD-RW

So apparently my Mac Pro has a defective superdrive in the lower slot, which for some reason beyond me always reports a specific brand of DVD-RW (Memorex) as "blank", even when they're not.

This has lead me to full erase (not a quick erase!) a very important DVD-RW that had some of my backup data on.

My extremely simple question is this:

Can data be recovered from a fully erased DVD-RW in any way? I can quite clearly see that the entire disk on the bottom has been overwritten by the drive (as the entire platter is a darker shade then when I originally bought the disks). I can also just barely make out the ring of data where my former backup resided (usually you can see where data has been written to a DVD-RW, since the shade of the medium gets darker every time you write to the disk).

I need to know if this is possible or not, or if I'm screwed (which I'm somewhat positive I am).

Once again, I did a full erase on this disk. Not a quick erase. Please do NOT reply and give me links to software that recovers data from a quick erase. I have already tried them all.

I am looking for something- anything- that might be able to still read the data off after a full erase. I don't even know if this is physically possible. If you know for certain that it isn't, please let me know as this will save me the time from continuing to look for a method to recover my data.

-SC
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Old May 27, 2013, 07:20 AM   #2
Eric Lee
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Hey SC,

Quote:
Originally Posted by ScottishCaptain
My extremely simple question is this:

Can data be recovered from a fully erased DVD-RW in any way?
The extremely simple answer to that would be: No

If you had done a quick erase there would be a chance to have recoverable data (still depending on software used to erase, as well as batch number of superdrive and firmware version), but for that you'd probably need special hardware equipment since you wouldn't be able to tell a superdrive where to look for the data on an quick erased DVD-RW. Chances might go up if the DVD-RW was treated as a DVD+RW during erasing - but as mentioned only for quick erase.

Problem with your full erase is that the drive erased the inner rings (where layout info is saved) as well as the data area. That means a recovery can neither guess where data was stored and even if you'd find tidbits of data you couldn't map it, because there is no layout indication. A highly specialized lab might be able to recover fractions of datastreams but this would be a highly complicated process you couldn't perform using standard hardware or software, you'd need tailored equipment. Even then recovery costs might be equal to a small car and you'd only get fragments (at best, probably not even this), not a full data-set.

If your data has been saved to a harddrive recently it would be more reasonable trying to recover the deleted data from said HDD.

Best regards,
Eric
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Old May 27, 2013, 07:29 AM   #3
justperry
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^^This, but I think you CAN'T recover anything for the following reason.

The data gets burned into the disk with a laser, with a full erase this means every single bit gets erased.
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Old May 27, 2013, 09:48 AM   #4
Fishrrman
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I know it's too late to help now with the fully-erased DVD, but in the future I'd suggest you use some media OTHER THAN Memorex. It doesn't have a good reputation.

The only CD's I've _ever_ had problems with were Memorex. Just bad from the get-go.

I'd recommend Verbatim brand in the future. Always good results with themů

I'm guessing that bad media (rather than a bad SuperDrive) had something to do with your original problems...
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Old May 27, 2013, 10:42 PM   #5
old-wiz
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Quote:
Originally Posted by Fishrrman View Post
I know it's too late to help now with the fully-erased DVD, but in the future I'd suggest you use some media OTHER THAN Memorex. It doesn't have a good reputation.

The only CD's I've _ever_ had problems with were Memorex. Just bad from the get-go.

I'd recommend Verbatim brand in the future. Always good results with themů

I'm guessing that bad media (rather than a bad SuperDrive) had something to do with your original problems...
Smarter still would be to have more than one backup, and not on optical media which is more prone to problems than other media.
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Old May 28, 2013, 09:07 AM   #6
Fishrrman
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"Smarter still would be to have more than one backup, and not on optical media which is more prone to problems than other media."

Have to agree with you there.

If one is going to use optical media, either CD or DVD, the best option is to use "non-rewritable" blanks (no "-RW"), and do at least two copies of each.

There's a new kind of optical media called "M-disc" that supposedly has a lifespan of 50-100 years, but I've never tried it and it doesn't seem to have caught on, since hard drive prices have come 'way down...
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Old May 28, 2013, 01:42 PM   #7
Eric Lee
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Hi.

Quote:
Originally Posted by Fishrrman View Post
There's a new kind of optical media called "M-disc" that supposedly has a lifespan of 50-100 years, but I've never tried it and it doesn't seem to have caught on, since hard drive prices have come 'way down...
M-Discs aren't that new and they will release M-Disc Blu-Ray this quarter (or already have done this, I'm not up to date on this). The theoretical lifespan of an M-Disk is ~1000 years, which is a tradeoff between lifespan and ease of manufacturing, because the data layer is attached to a polycarbonate-layer just as a normal DVD and polycarbonat will eventually degrade after about 900 - 1000 years.

I agree that it seems like M-Discs haven't caught on and only few people are using them. As you already said that might be because people do have more trust in (and access to cheap) harddrives and "cloud" storage. It is also worth mentioning that you need special drives to burn M-Discs (laser temp. > ~510 ░C) and people aren't buying expensive hardware just to burn a few discs. Additionally businesses might rely on things like Syylex permanent storage and not M-Disc, because it's based on a higher standard, has higher OD, you don't have to buy equipment and permanent storage isn't prone to the write errors you know from DVD (which can also happen to M-Disc).

Quote:
Originally Posted by ScottishCaptain
or if I'm screwed (which I'm somewhat positive I am).
If you want to try and recover your data from any harddrive which it might have resided on let me know if you need advice on any tools worth trying.

Best regards,
Eric
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