Mdoc: fix hard sentence breaks.
Approved by: des (mentor)
This commit is contained in:
Hiten Pandya
parent
8e9a665fde
commit
f6c211ae08
@ -108,14 +108,16 @@ and
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.It Dv DIOCSDINFO
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.Pq Li "struct disklabel"
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Read or write the in-core copy of the disklabel for the
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drive. The disklabel is initialized with information
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drive.
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The disklabel is initialized with 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. This structure is defined in
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the information printed at boot.
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This structure is defined in
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.Xr disklabel 5 .
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.It Dv CDIOCCAPABILITY
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.Pq Li "struct ioc_capability"
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Retrieve information from the drive on what features it supports. The
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information is returned in the following structure:
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Retrieve information from the drive on what features it supports.
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The information is returned in the following structure:
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.Bd -literal -offset indent
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struct ioc_capability {
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u_long play_function;
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@ -177,8 +179,8 @@ struct ioc_capability {
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.Ed
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.It Dv CDIOCPLAYTRACKS
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.Pq Li "struct ioc_play_track"
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Start audio playback given a track address and length. The structure
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is defined as follows:
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Start audio playback given a track address and length.
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The structure is defined as follows:
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.Bd -literal -offset indent
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struct ioc_play_track
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{
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@ -190,8 +192,8 @@ struct ioc_play_track
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.Ed
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.It Dv CDIOCPLAYBLOCKS
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.Pq Li "struct ioc_play_blocks"
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Start audio playback given a block address and length. The structure
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is defined as follows:
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Start audio playback given a block address and length.
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The structure is defined as follows:
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.Bd -literal -offset indent
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struct ioc_play_blocks
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{
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@ -202,7 +204,8 @@ struct ioc_play_blocks
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.It Dv CDIOCPLAYMSF
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.Pq Li "struct ioc_play_msf"
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Start audio playback given a `minutes-seconds-frames' address and
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length. The structure is defined as follows:
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length.
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The structure is defined as follows:
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.Bd -literal -offset indent
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struct ioc_play_msf
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{
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@ -247,8 +250,9 @@ struct ioc_toc_header {
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.Ed
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.It Dv CDIOREADTOCENTRYS
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.Pq Li "struct ioc_read_toc_entry"
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Return information from the table of contents entries mentioned. (Yes, this
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command name is misspelled.) The argument structure is defined as follows:
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Return information from the table of contents entries mentioned.
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.Pq Yes, this command name is misspelled.
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The argument structure is defined as follows:
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.Bd -literal -offset indent
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struct ioc_read_toc_entry {
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u_char address_format;
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@ -263,8 +267,8 @@ and pointed to by
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.Li data .
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.It Dv CDIOCSETPATCH
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.Pq Li "struct ioc_patch"
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Attach various audio channels to various output channels. The
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argument structure is defined thusly:
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Attach various audio channels to various output channels.
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The argument structure is defined thusly:
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.Bd -literal -offset indent
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struct ioc_patch {
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u_char patch[4];
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@ -274,8 +278,8 @@ struct ioc_patch {
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.It Dv CDIOCGETVOL
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.It Dv CDIOCSETVOL
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.Pq Li "struct ioc_vol"
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Get (set) information about the volume settings of the output channels. The
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argument structure is as follows:
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Get (set) information about the volume settings of the output channels.
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The argument structure is as follows:
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.Bd -literal -offset indent
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struct ioc_vol
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{
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@ -314,17 +318,20 @@ disc. Not all drives support this feature.
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Eject the
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.Tn CD-ROM .
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.It Dv CDIOCCLOSE
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Tell the drive to close its door and load the media. Not all drives
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support this feature.
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Tell the drive to close its door and load the media.
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Not all drives support this feature.
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.It Dv CDIOCPITCH
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.Pq Li "struct ioc_pitch"
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For drives that support it, this command instructs the drive to play
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the audio at a faster or slower rate than normal. Values of
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the audio at a faster or slower rate than normal.
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Values of
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.Li speed
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between -32767 and -1 result in slower playback; a zero value
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indicates normal speed; and values from 1 to 32767 give faster
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playback. Drives with less than 16 bits of resolution will silently
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ignore less-significant bits. The structure is defined thusly:
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playback.
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Drives with less than 16 bits of resolution will silently
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ignore less-significant bits.
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The structure is defined thusly:
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.Bd -literal -offset indent
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struct ioc_pitch
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{
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@ -338,10 +345,13 @@ When a
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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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disklabel and information held within the kernel.
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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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open file descriptors referencing the device.
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During this period, all
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new open attempts will be rejected.
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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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parameters (including disklabel) for the drive.
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.Pp
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@ -360,28 +370,35 @@ some of the more common `broken'
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.Tn CD-ROM
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drives; however, this is not yet under way.
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.Sh CHANGER OPERATION
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This driver has built-in support for LUN-based CD changers. A LUN-based CD
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This driver has built-in support for LUN-based CD changers.
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A LUN-based CD
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changer is a drive that can hold two or more CDs, but only has one CD
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player mechanism. Each CD in the drive shows up as a separate logical unit
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player mechanism.
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Each CD in the drive shows up as a separate logical unit
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on the
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.Tn SCSI
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bus. The
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.Nm
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driver automatically recognizes LUN-based changers, and routes commands for
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changers through an internal scheduler. The scheduler prevents changer
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changers through an internal scheduler.
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The scheduler prevents changer
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"thrashing", which is caused by sending commands to different LUNs in the
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changer at the same time.
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.Pp
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The scheduler honors minimum and maximum time
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quanta that the driver will spend on a particular LUN. The minimum time
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quanta that the driver will spend on a particular LUN.
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The minimum time
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is the guaranteed minimum amount of time that the driver will spend on a
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given LUN, even if there is no outstanding I/O for that LUN. The maximum
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given LUN, even if there is no outstanding I/O for that LUN.
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The maximum
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time is the maximum amount of time the changer will spend on a LUN if there
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is outstanding I/O for another LUN. If there is no outstanding I/O for
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is outstanding I/O for another LUN.
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If there is no outstanding I/O for
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another LUN, the driver will allow indefinite access to a given LUN.
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.Pp
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The minimum and maximum time quanta are configurable via kernel options and
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also via sysctl variables. The kernel options are:
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also via sysctl variables.
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The kernel options are:
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.Pp
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.Bl -item -compact
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.It
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@ -401,12 +418,14 @@ The sysctl variables are:
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.Pp
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It is suggested that the user try experimenting with the minimum and
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maximum timeouts via the sysctl variables to arrive at the proper values
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for your changer. Once you have settled on the proper timeouts for your
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for your changer.
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Once you have settled on the proper timeouts for your
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changer, you can then put them in your kernel config file.
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.Pp
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If your system does have a LUN-based changer, you may notice that the
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probe messages for the various LUNs of the changer will continue to appear
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while the boot process is going on. This is normal, and is caused by the
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while the boot process is going on.
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This is normal, and is caused by the
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changer scheduling code.
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.Sh FILES
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.Bl -tag -width /dev/cd[0-9][a-h] -compact
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@ -434,11 +453,14 @@ commands.
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There is no mechanism currently to set different minimum and maximum
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timeouts for different CD changers; the timeout values set by the kernel
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options or the sysctl variables apply to all LUN-based CD changers in the
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system. It is possible to implement such support, but the sysctl
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system.
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It is possible to implement such support, but the sysctl
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implementation at least would be rather inelegant, because of the current
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inability of the sysctl code to handle the addition of nodes after compile
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time. Thus, it would take one dynamically sized sysctl variable and a
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userland utility to get/set the timeout values. Implementation of separate
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time.
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Thus, it would take one dynamically sized sysctl variable and a
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userland utility to get/set the timeout values.
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Implementation of separate
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timeouts for different CD devices in the kernel config file would likely
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require modification of
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.Xr config 8
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