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CD(9)		      DragonFly Kernel Developer's Manual		 CD(9)


cd -- CDROM driver for the CAM SCSI subsystem


The cd device driver provides a read only interface for CDROM drives (SCSI type 5) and WORM drives (SCSI type 4) that support CDROM type com- mands. Some drives don't behave as the driver expects. See the section QUIRKS for info on possible flags.


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 unim- plemented in the CAM cd driver. 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.


/sys/bus/cam/scsi/scsi_cd.c is the driver source file.


cd(4), scsi(4)


The cd manual page first appeared in FreeBSD 2.2.


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>. DragonFly 5.1 October 10, 1998 DragonFly 5.1

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