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Recovering Quick-Erased Discs – Part 1

October 4, 2011

Let’s say you have a DVD-RW that has been quick-erased… maybe the person that had it wanted to destroy the information that was there or perhaps you thought you had a different disc in the drive and clicked Yes too many times.

Did you know that quick-erase simply clears some basic control information on the disc? What is commonly called “quick-erase” is termed “Minimally blank the disc” in the standard and is described as follows:

Erases only the PMA, first session TOC and the pre-gap of the first track. This is used for blanking a disc quickly. After completion of this command the disc is treated as a blank disc. Caution shall be exercised when using this command as the program area still contains user data.

What this means is that all of the information that was on the disc is still there, but any drive you put the disc into will treat it as a blank disc.

So how do you go about accessing the data that is still there on the disc? There are two well-known techniques for doing this – the first one is pretty risky but easily done, the second is harder to do but does not place the data at any risk at all.

The first technique for accessing what is on a quick-erased disc is to format it. This works with CD-RW and DVD-RW discs but doesn’t work at all with DVD+RW. You simply put the disc into a drive on a computer with some type of drag-and-drop writing software (aside from Windows) and select “format” when prompted. The light on the drive will flicker a bit and you will hear some movement and then the format operation will begin. The key to this technique is to remove power from the drive almost immediately upon the beginning of the format operation. The beginning of the disc will be written to, indicating that there is lots of data on the disc but the format operation will not have reached the point where the old data is yet.

Obviously, this is a tricky sort of thing to do. If you pull the plug too quickly you will still have a blank disc on your hands and nothing will have changed. If you wait too long data on the disc will be destroyed. An external drive is best for this sort of thing so you aren’t powering down your whole computer suddenly. No, I don’t mean shutting down the computer here – I mean disconnecting the drive from power, usually by unplugging it.

It can take some practice to get this technique down and some of the tries are going to make a disc permanently unusable. Other than the ease of the technique, I don’t find anything to recommend it.

The other technique involves swapping discs in a drive and requires some work and some special or specially prepared hardware. It will be described in detail in part 2 of this.

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