185 lines
5.2 KiB
Groff
185 lines
5.2 KiB
Groff
.Dd August 27, 1993
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.Dt CD 4
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.Os FreeBSD
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.Sh NAME
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.Nm cd
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.Nd scsi cdrom driver
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.Sh SYNOPSIS
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.Nm device cd
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.Nm device cd1 target 4 lun 0
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.Sh DESCRIPTION
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The
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.Xr cd
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driver provides support for a
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.Em scsi
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cdrom. It allows the cdrom
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to be divided up into a set of pseudo devices called
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.Em partitions.
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In an attempt to look like regular disks the
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.Nm
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driver synthesises a partition table, with one partition covering the entire
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cdrom. A user might (for some amazing reason) add another partition to the
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cdrom by using disklabel, but it will last only until the cdrom is unmounted.
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A Partition can have both a
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.Em raw
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interface
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and a
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.Em Block mode
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interface.
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In general the interfaces are similar to those described by
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.Xr wd 4
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or
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.Xr sd 4 .
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.Pp
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Where the
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.Xr wd 4
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device has a fairly low level interface to the system,
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.Em SCSI
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devices have a much higher level interface and talk to the system via
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a
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.Em SCSI Adapter
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and a
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.Em Scsi Adapter driver
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e.g.
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.Xr AHA1542 .
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A scsi adapter must also be separatly configured into the system
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before a scsi cdrom can be configured.
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.Pp
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As the scsi adapter is probed during boot, the
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.Em SCSI
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bus is scanned for devices. Any devices found which answer as 'Readonly'
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type devices will be 'attached' to the
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.Nm
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driver.
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In FreeBSD releases prior to 2.1, the first found will be attached as
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.Em cd0
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and the next,
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.Em cd1
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etc.
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Beginning in 2.1 it is possible to specify what cd unit a device should
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come on line as; refer to
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.Xr scsi 4
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for details on kernel configuration.
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.Pp
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The system utility
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.Xr disklabel 1
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may be used to read the synthesized
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.Xr disklabel 5
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structure, which will contain correct figures for the size of the cdrom
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should that information be required.
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.Pp
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.Sh KERNEL CONFIGURATION
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Any number of cdroms may be attached to the system regardless of system
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configuration as all resources are dynamically allocated.
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.Pp
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.Sh IOCTLS
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The following
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.Xr ioctl 2
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calls apply to scsi cdroms
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in the header files
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.Em sys/cdio.h.
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and
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.Em sys/disklabel.h
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.Bl -tag -width CDIOCPLAYAUDIO____
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.It Dv DIOCGDINFO
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Read, from the kernel, the in-core copy of the disklabel for the
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drive. This will be a ficticious disklabel it will contain information
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read from the scsi inquiry commands, and should be the same as
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the information printed at boot.
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.It Dv DIOCSDINFO
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Give the driver a new disklabel to use. The driver will NOT try write the new
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disklabel to the disk. (ok?)
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.It CDIOCPLAYTRACKS
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Start Audio playback given a track address and length.
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.It CDIOCPLAYBLOCKS
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Start Audio playback given a block address and length.
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.It CDIOCPLAYMSF
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Start Audio playback given a 'Minutes/ seconds/ frames' address and length.
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.It CDIOCREADSUBCHANNEL
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Read information from the subchannel at the location specified.
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.It CDIOREADTOCHEADER
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Return summary information about the table of contents for the mounted cdrom.
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.It CDIOREADTOCENTRYS
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Return information from the table of contents entries mentionned.
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.It CDIOCSETPATCH
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Attach various audio channels to various output channels.
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.It CDIOCGETVOL
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Get information about the volume settings of the output channels.
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.It CDIOCSETVOL
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Change the volume settings of the output channels.
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.It CDIOCSETMONO
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Patch all out[put channels to all source channels.
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.It CDIOCSETSTERIO
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Patch left source channel to the left output channel and the right
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source channel to the right output channel.
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.It CDIOCSETMUTE
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Mute output without changing the volume settings.
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.It CDIOCSETLEFT
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Attach both output channels to the left source channel.
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.It CDIOCSETRIGHT
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Attach both output channels to the right source channel.
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.It CDIOCSETDEBUG
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Turn on debugging for the appropriate device.
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.It CDIOCCLRDEBUG
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Turn off debugging for the appropriate device.
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.It CDIOCPAUSE
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Pause audio play, do not reset the location of the read-head.
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.It CDIOCRESUME
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Resume audio play, Start at the location of the pause.
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.It CDIOCRESET
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Reset the drive.
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.It CDIOCSTART
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Tell the drive to spin-up the cdrom.
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.It CDIOCSTOP
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Tell the drive to spin-down the cdrom.
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.It CDIOCEJECT
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Eject the cdrom.
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.El
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.Pp
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In addition the general
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.Xr scsi 4
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ioctls may be used with the
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.Nm
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driver, if used against the fourth (raw/whole disk) partiton. (e.g. rcd0d)
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.Sh NOTES
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When a cdrom is changed in a drive controlled by the
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.Nm
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driver, then the act of changing the media will invalidate the
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disklabel and information held within the kernel. To stop corruption,
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All accesses to the device will be discarded until there are no more
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open file descriptors referencing the device. During this period, all
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new open attempts will be rejected. When No more open file descriptors
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reference the device, the first next open will load a new set of
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figures (including disklabel) for the drive.
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The Audio code in the
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.Nm
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driver only support SCSI2 standard audio commands. As there are many cdrom
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manufacturers who have not followed the standard well, there are many
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cdroms for which audio will not work. Some work is planned to support
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some of the more common 'broken' cdrom drives however this is not yet
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under way.
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.Sh FILES
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.Bl -tag -width /dev/rcd[0-9][a-h] -compact
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.It Pa /dev/cd[0-9][a-h]
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block mode scsi disks
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.It Pa /dev/rcd[0-9][a-h]
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raw scsi disks
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.El
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.Sh DIAGNOSTICS
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None.
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.Sh SEE ALSO
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.Xr disklabel 1
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.Xr disklabel 5
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.Xr wd 4
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.Xr sd 4
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.Sh HISTORY
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This
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.Nm
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driver appeared in 386BSD 0.1.
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