NAME
cd —
CDROM driver for the CAM SCSI
subsystem
DESCRIPTION
Thecd device driver provides a read only interface for
CDROM drives (SCSI type 5) and WORM drives (SCSI type 4) that support CDROM
type commands. Some drives don't behave as the driver expects. See the section
QUIRKS for info on possible flags.
QUIRKS
Each CD-ROM device can have different interpretations of the SCSI spec. This can lead to drives requiring special handling in the driver. The following is a list of quirks that the driver recognize.
CD_Q_NO_TOUCH- This flag tell the driver not to probe the drive at attach time to see if
there is a disk in the drive and find out what size it is. This flag is
currently unimplemented in the CAM
cddriver. CD_Q_BCD_TRACKS- This flag is for broken drives that return the track numbers in packed BCD instead of straight decimal. If the drive seems to skip tracks (tracks 10-15 are skipped) then you have a drive that is in need of this flag.
CD_Q_NO_CHANGER- This flag tells the driver that the device in question is not a changer. This is only necessary for a CDROM device with multiple luns that are not a part of a changer.
CD_Q_CHANGER- This flag tells the driver that the given device is a multi-lun changer. In general, the driver will figure this out automatically when it sees a LUN greater than 0. Setting this flag only has the effect of telling the driver to run the initial read capacity command for LUN 0 of the changer through the changer scheduling code.
FILES
- /sys/bus/cam/scsi/scsi_cd.c
- is the driver source file.
SEE ALSO
HISTORY
The cd manual page first appeared in
FreeBSD 2.2.
AUTHORS
This manual page was written by John-Mark Gurney <gurney_j@efn.org>. It was updated for CAM and FreeBSD 3.0 by Kenneth Merry <ken@FreeBSD.org>.