discussions on the mailing lists, and to a number of unofficial patches for supporting the Pioneer DVD-R A03, the first DVD writer to reach mass market, and forks of cdrecord: Mandrake shipped a version called cdrecord-dvdhack, whereas Redhat had dvdrecord. Hardware access controversy Unlike cdrkit and libburnia, which use device files to access the hardware, cdrtools uses a different method known as CAM (for Common Access Method), which is available on many operating systems, including some which lack device files or only allow the kernel to access them. This difference has turned into a controversy: some Linux users claim that the method used by cdrtools is not appropriate, while some Linux users claim that the users of cdrtools do not need to know which method is used. In cdrtools, burning optical media (such as CDs, DVDs and Blu-rays discs) is done through the SCSI interface. Users of systems with more than one burning device need to provide a SCSI device (which is identified by a triplet of numbers, scsibus,target,lun). Users of systems with only one burning device, however, do not need to specify the SCSI device since cdrtools is able to find it. By 2002 more and more burners were using the ATAPI interface. Linux 2.6 allowed the users to detect the SCSI ID of a device from its UNIX device path (/dev/hdX) and a patch was published that made identifying the burner device for cdrecord simpler by allowing the user to specify the /dev/hdX device name (or even default to a udev managed link such as /dev/cdrw). Schilling, however, rejected this approach as well as other modifications used by Linux distributions, with the rationale that it would make the software more complex and less portable as this function was not available on other UNIX systems. Linus Torvalds states that SCSI LUNs should not be used for addressing devices on Linux, because these numbers are not unique, and do not make sense for many devices anymore (many devices will report 0:0:0 fake numbers). Instead Torvalds recommends that devices should be addressed via their UUID, physical connection, or an alias symlink as managed by udev on Linux. Torvalds pointed out that the ioctl's have been kept to ensure cdrecord compatibility and do not return a meaningful value. License compatibility controversy By 2004, Linux distributions were maintaining a number of unofficial changes such as allowing the use of /dev/hdX device names and