Libburn is a library by which preformatted data get onto optical media: CD, DVD, BD (Blu-Ray). On Linux it uses either /dev/sgN (on kernel 2.4 with ide-scsi, or optional with concurrent operation of multiple drives) or /dev/srM (kernel 2.6 and newer), /dev/hdX ( on kernel 2.6). Libburn also offers a facility for reading data blocks from its drives without using the normal block device i/o, which has its advantages and disadvantages. It seems appropriate, nevertheless, to do writing and reading via the same channel. On several Linux systems, the block device driver needs reloading of the drive tray in order to make available freshly written data. The libburn read function does not need such a reload. Audio CD can be written and read.