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I have a disc burned and locked by my coworker with only a few megs of data. Is there a way to know if he used a CD or a DVD for media?

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4 Answers 4

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You can't just through physical examination. Both are 120mm in diameter and 1.2mm thick.

If the manufacturer hasn't written something descriptive on the label (or on the text by the spindle hole) then you can't tell the difference just through observation.

If you have access to a high power microscope you could examine the surface of the disk as the pit sizes differ for CDs and DVDs, you'll find the pit are 0.74 µm for DVD versus 1.6 µm for CDs.

[Most DVD writing software (like CD burner XP or Nero) will tell you what type of disk is in the drive.]

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All recordable DVDs I've seen look like they are two 0.6mm thick discs glued together (and they are). –  grawity Jul 16 '09 at 14:39
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yes. DVD's have the recording media between 2 layers of polycarbonate, while CD have the recording media on one side. pro tip: CD's are way easier to bork - even factory pressed ones –  geocoin Jul 16 '09 at 14:48
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No CDs are 120mm, while DVDs are 12cm. See completely different :P –  Brad Gilbert Jul 16 '09 at 15:21
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  • Put it in a CD drive and see if it works.

  • Often they say on the front of the media

  • I think there are some markings near where the spindle goes which may indicate it

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As has been mentioned before in the comments, there is most definitely a way to determine if a disc is a CD or DVD through physical examination. It is actually quite obvious, DVDs are two sheets of polycarbonate sandwiching the recording layer, look at the edge of the disc, if you can see a thin trench down the middle, then it is a DVD.

They also sound different when you tap them against something, a DVD is a slightly lower, more dull thud. They also feel different to me, but that might just be me. :)

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Sometimes DVD media will have a different color on the writable side. I've seen some that are bluish and some that have a purple hue. If that's the case, it's probably a DVD. But Simon Stevens is right, you generally can't tell through physical examination unless the manufacturer has tinted the disk.

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I have seen CDRs with those colors as well. –  Stefan Thyberg Jul 16 '09 at 14:17
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