The device refers to scsibus/target/lun of the drive. Communication on SunOS is done with the SCSI general driver scg. Other operating systems are using a library simulation of this driver. Possible syntax is: dev= scsibus,target,lun or dev= target,lun. In the latter case, the drive has to be connected to the default SCSI bus of the machine. Scsibus, target and lun are integer numbers. Some operating systems or SCSI transport implementations may require to specify a filename in addition. In this case the correct syntax for the device is: dev= devicename:scsibus,target,lun or dev= devicename:target,lun. If the name of the device node that has been specified on such a system refers to exactly one SCSI device, a shorthand in the form dev= devicename:@ or dev= devicename:@,lun may be used instead of dev= devicename:scsibus,target,lun.
To access remote SCSI devices, you need to prepend the SCSI device name by
a remote device indicator. The remote device indicator is either
A valid remote SCSI device name may be: REMOTE:user@host: to allow remote SCSI bus scanning or REMOTE:user@host:1,0,0 to access the SCSI device at host connected to SCSI bus # 1,target 0 lun 0.
To make readcd portable to all UNIX platforms, the syntax dev= devicename:scsibus,target,lun is preferred as is hides OS specific knowledge about device names from the user. A specific OS must not necessarily support a way to specify a real device file name nor a way to specify scsibus,target,lun.
Scsibus 0 is the default SCSI bus on the machine. Watch the boot messages for more information or look into /var/adm/messages for more information about the SCSI configuration of your machine. If you have problems to figure out what values for scsibus,target,lun should be used, try the -scanbus option of cdrecord.
For the non bus scanning case, a typical device specification is dev=6,0 . If a filename must be provided together with the numerical target specification, the filename is implementation specific. The correct filename in this case can be found in the system specific manuals of the target operating system. On a FreeBSD system without CAM support, you need to use the control device (e.g. /dev/rcd0.ctl). A correct device specification in this case may be dev=/dev/rcd0.ctl:@ .
On Linux, drives connected to a parallel port adapter are mapped to a virtual SCSI bus. Different adapters are mapped to different targets on this virtual SCSI bus.
If no dev option is present, cdrecord will try to get the device from the CDR_DEVICE environment.
If the argument to the dev= option does not contain the characters ',', '/', '@' or ':', it is interpreted as an label name that may be found in the file /etc/default/cdrecord (see FILES section).
When using scgckeck with the broken Linux SCSI generic driver. You should note that scgcheck uses a hack, that tries to emulate the functionality of the scg driver. Unfortunately, the sg driver on Linux has several severe bugs:
A typical error message for a SCSI command looks like:
readcd: I/O error. test unit ready: scsi sendcmd: no error CDB: 00 20 00 00 00 00 status: 0x2 (CHECK CONDITION) Sense Bytes: 70 00 05 00 00 00 00 0A 00 00 00 00 25 00 00 00 00 00 Sense Key: 0x5 Illegal Request, Segment 0 Sense Code: 0x25 Qual 0x00 (logical unit not supported) Fru 0x0 Sense flags: Blk 0 (not valid) cmd finished after 0.002s timeout 40s
The second line prints the SCSI command descriptor block for the failed command.
The third line gives information on the SCSI status code returned by the command, if the transport of the command succeeds. This is error information from the SCSI device.
The fourth line is a hex dump of the auto request sense information for the command.
The fifth line is the error text for the sense key if available, followed by the segment number that is only valid if the command was a copy command. If the error message is not directly related to the current command, the text deferred error is appended.
The sixth line is the error text for the sense code and the sense qualifier if available. If the type of the device is known, the sense data is decoded from tables in scsierrs.c . The text is followed by the error value for a field replaceable unit.
The seventh line prints the block number that is related to the failed command and text for several error flags. The block number may not be valid.
The eight line reports the timeout set up for this command and the time that the command realy needed to complete.
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