The recording industry is testing technology that would prevent consumers from making copies of CD "burns," a piracy defense that could put some significant new restrictions on legally purchased music. Tools under review by the major labels would limit the number of backups that could be made from ordinary compact discs and prevent copied, or "burned," versions from being used to create further copies, according to Macrovision and SunnComm International, rivals that are developing competing versions of the digital rights management (DRM) software. SunnComm said a version of its new "secure burning" technology is already being tested by BMG Music...