cbb2063e__SG_IO_ioctl_in_the_2_6_series_inimum_permission_requirements_Comments
[SCSI command] READ CDVD CAPACITY [(draft) standard] SBC-3, MMC-4 [sg driver requires] O_RDONLY O_RDONLY [Comments] 
Strange (old ?) name from cdrom.h . Actually is READ CAPACITY.
Linux SG_IO ioctl in the 2.6 series
Comments