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SCGSKELETON(1L) Schily's USER COMMANDS SCGSKELETON(1L)
NAME
scgskeleton - Skeleton program for SCSI transport using libscg
SYNOPSIS
scgskeleton dev=device [ options ]
DESCRIPTION
Scgskeleton is s skeleton program to demonstrate the interfaces and
capabilities of the SCSI transport library libscg.
Device naming
For a list of possible device name parameters call scgskeleton -scanbus
or scgskeleton dev=help and then use the right dev= parameter based on
the device listing.
OPTIONS
-help Prints a short summary of the p options and exists.
-version
Print version information and exit.
dev=target
Set the SCSI target for the CD/DVD/BluRay-Recorder, see notes
above. A typical target device specification is dev=1,6,0 . 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:@ .
General SCSI addressing
The target device to the dev= option refers to
scsibus/target/lun of the CD/DVD/BluRay-Recorder. 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 CD/DVD/BluRay-Recorder 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.
Remote SCSI addressing
To access remote SCSI devices, you need to prepend the SCSI
device name by a remote device indicator. The remote device
indicator is either REMOTE:user@host: or REMOTE:host: 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
IDE (ATA) transport. You may need to specify an alternate
transport layer on the command line if your OS does not
implement a fully integrated kernel driver subsystem that allows
one to access any drive using SCSI commands via a single unique
user interface.
To access SCSI devices via alternate transport layers, you need
to prepend the SCSI device name by a transport layer indicator.
The transport layer indicator may be something like USCSI: or
ATAPI:. To get a list of supported transport layers for your
platform, use dev= HELP:
Portability Background
To make scgskeleton portable to all UNIX platforms, the syntax
dev= devicename:scsibus,target,lun is preferred as it hides OS
specific knowledge about device names from the user. A specific
OS may 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
scgskeleton described below.
Using logical names for devices
If no dev option is present, scgskeleton will try to get the
device from the CDR_DEVICE environment.
If a file /etc/default/cdrecord exists, and if the argument to
the dev= option or the CDR_DEVICE environment does not contain
the characters ',', '/', '@' or ':', it is interpreted as a
device label name that was defined in the file
/etc/default/cdrecord (see FILES section).
Autotarget Mode
If no dev= option and no CDR_DEVICE environment is present, or
if it only contains a transport specifyer but no address
notation, scgskeleton tries to scan the SCSI address space for
CD-ROM drives. If exactly one is found, this is used by
default.
timeout=#
Set the default SCSI command timeout value to # seconds. The
default SCSI command timeout is the minimum timeout used for
sending SCSI commands. If a SCSI command fails due to a
timeout, you may try to raise the default SCSI command timeout
above the timeout value of the failed command. If the command
runs correctly with a raised command timeout, please report the
better timeout value and the corresponding command to the author
of the program. If no timeout option is present, a default
timeout of 40 seconds is used.
debug=#, -d
Set the misc debug value to # (with debug=#) or increment the
misc debug level by one (with -d). If you specify -dd, this
equals to debug=2. This may help to find problems while opening
a driver for libscg. as well as with sector sizes and sector
-silent, -s
Do not print out a status report for failed SCSI commands.
-v Increment the level of general verbosity by one. This is used
e.g. to display the progress of the process.
-V Increment the verbose level with respect of SCSI command
transport by one. This helps to debug problems during the
process, that occur in the CD-Recorder. If you get
incomprehensible error messages you should use this flag to get
more detailed output. -VV will show data buffer content in
addition. Using -V or -VV slows down the process. -scanbus
Scan all SCSI devices on all SCSI busses and print the inquiry
strings. This option may be used to find SCSI address of the
devices on a system. The numbers printed out as labels are
computed by: bus * 100 + target
scgopts=list
A comma separated list of SCSI options that are handled by
libscg. The implemented options may be updated independently
from applications. Currently, one option: ignore-resid is
supported to work around a Linux kernel bug.
ts=# Set the maximum transfer size for a single SCSI command to #.
The syntax for the ts= option is the same as for cdrecord fs=#
or sdd bs=#.
If no ts= option has been specified, scgskeleton defaults to a
transfer size of 256 kB. If libscg gets lower values from the
operating system, the value is reduced to the maximum value that
is possible with the current operating system. Sometimes, it
may help to further reduce the transfer size or to enhance it,
but note that it may take a long time to find a better value by
experimenting with the ts= option.
EXAMPLES
ENVIRONMENT
RSH If the RSH environment is present, the remote connection will
not be created via rcmd(3) but by calling the program pointed to
by RSH. Use e.g. RSH=/usr/bin/ssh to create a secure shell
connection.
Note that this forces cdrecord to create a pipe to the rsh(1)
program and disallows cdrecord to directly access the network
socket to the remote server. This makes it impossible to set up
performance parameters and slows down the connection compared to
a root initiated rcmd(3) connection.
RSCSI If the RSCSI environment is present, the remote SCSI server will
not be the program /opt/schily/sbin/rscsi but the program
pointed to by RSCSI. Note that the remote SCSI server program
name will be ignored if you log in using an account that has
been created with a remote SCSI server program as login shell.
SEE ALSO
cdrecord(1), scg(4), rcmd(3), ssh(1).
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 first line gives information about the transport of the command.
The text after the first colon gives the error text for the system call
from the view of the kernel. It usually is: I/O error unless other
problems happen. The next words contain a short description for the
SCSI command that fails. The rest of the line tells you if there were
any problems for the transport of the command over the SCSI bus. fatal
error means that it was not possible to transport the command (i.e. no
device present at the requested SCSI address).
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 really needed to complete.
BUGS
None currently known.
Mail bugs and suggestions to schilytools@mlists.in-berlin.de or open a
ticket at https://codeberg.org/schilytools/schilytools/issues
The mailing list archive may be found at:
https://mlists.in-berlin.de/mailman/listinfo/schilytools-mlists.in-berlin.de
AUTHORS
Joerg Schilling and the schilytools project authors.
SOURCE DOWNLOAD
The source code for scgskeleton is included in the schilytools project
and may be retrieved from the schilytools project at Codeberg at:
Joerg Schilling 2022/10/06 SCGSKELETON(1L)