Thanks to Martin H for posting the following link in Sebastian's recent DAE test results thread: http://www.xbitlabs.com/articles/storage/d...r-px760a_7.html


I can create the 'normal' one just fine. Does anyone know how to create the 'bad' disc? If it's done simply with the app and a blank CD-R, I can't figure it out for the life of me. The program helps have nothing on this, and google has also come up empty.

Create the "normal" DAE qualty test disc, scratch it and then run the error test. Creating an error test disc doesn't work for me either, probably because you need a special CD-R.

Could be that. Also, wouldn't you need to read the image of the scratched disc, so the app knows where the C2 errors are supposed to be? Otherwise, you're going to always get 99.99% C2 accuracy when comparing it to the normal disc.

EDIT: Just got reffered to here: http://cdrlabs.com/reviews/index.php?revie...sts_DAE_Quality

No, because Nero CDSpeed knows what to expect (after all, you used it to create the test disc, so it knows what it put on the disc). When you read the disc back, it compares the data it received from the drive against its internally stored data and checks for differences.

But the original stored data never had any C2 errors, so how does a testing application know how many C2 errors on a damaged disc were missed if it doesn't know where the errors are beforehand?

Or is my whole understanding of C2 testing off? Is 'C2 errors missed' more accurately stated as 'C2 unrecoverable errors'? I always read it as errors the drive couldn't find/identify.

Dude, you burn the disc. Nero CDSpeed knows what it burned. When you extract, the unit reports C2 errors which the application fetches. At the same time it compares the data it received from the data it expected. If there is a difference and no C2 error was reported, the drive missed a C2 error.

OK, I wasn't getting how the test cross-checks the data difference with the error reports. I assumed (falsely) the errors had to be part of the original data set. Thanks for the explanation; sorry it took a few times for me to get it.

Any recommendations how to scratch the disc the most effectively ?

Depends what you want to test. For C2, I randomly scratched the disk and looked how many errors slipped through. If you want to test how effective the drive's error correction is, maybe use some scratches that get wider and wider.

That was meant to be a joke, but thanks for the answer anyways