From: "generalstuff" -- Anna Summers >What is the difference between DVD+ and DVD- ? In a nutshell, different designs of the burners (and the disks). There were two competing "camps" of burner designers. You might think of it as the same as the VHS vs. Betamax wars of the tape formats of years ago in video recording... The biggest difference is that the tape formats were never playable on the same machine... The good news is that all burner drives "could have been" made to conform with both sets of specifications, and lots (if not almost all newer drives) have been compatible with both design specifications for quite some time... (Most drives can not be "upgraded" to use both if those features were not "built-in" originally...) Here is a random link from Google that shows "all" the types of disks, but is not "too helpful" with your specific question... http://www.ahinc.com/dvd.html With so many types of disks, you can see why a drive manufacturer might want to stick with only a few specifications to cut costs. Most drive manufacturers found this false economy since specification limited burner drives are hard to sell, other than to "niche" markets... Rick Glazier Visit our website regularly for FAQs, articles, how-to's, tech tips and much more http://freepctech.com