Cactus Data Shield (CDS) is a form of CD/DVD copy protection for audio compact discs developed by Israeli company Midbar Technologies.
As of September 2006, all of Macrovision's CD copy protection products, including CDS, had quietly disappeared from their website.
[2] The December 2006 issue of Billboard announced that EMI had decided to abandon Copy Control worldwide.
In addition the disc contains a second (data) session and a software player configured for auto-play with a lower-quality, compressed version of the audio for it to play.
Newer versions of Windows since Vista have fixed the auto-run vulnerability thus all the user needs to do is simply choose not to run the software.
Some older CD drives would only see the second session erroneous values (such as time and track type) and were not able to copy or play these.
Because these missing frames occur at points where the waveform was nearly a straight line anyway, this interpolation is very accurate and generally transparent to the user.
Some older drives simply ignore the subcode and "play" the data frames, resulting in loud audio glitches.