Schily's USER COMANDS READCD(1)
NAME
readcd - read or write data Compact Discs
SYNOPSIS
readcd [ dev=device ][ options ]
DESCRIPTION
Readcd is used to read or write Compact Discs.
The device refers to scsibus/target/lun of the drive. Com-
munication 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, 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,
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 SCSI device at host connected to SCSI bus #
1,target 0 lun 0.
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:
To make readcd portable to all UNIX platforms, the syntax
dev= devicename:scsibus,target, 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.
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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 confi-
guration 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.
OPTIONS
If no options except the dev= option have been specified,
readcd goes into interactive mode. Select a primary func-
tion and then follow the instructions.
-version
Print version information and exit.
dev=target
Sets the SCSI target for the drive, see notes above. 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 sup-
port, 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 CDRDEVICE 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).
If no dev= option is present, or if the dev= option
only contains a transport specifyer but no address,
readcd 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
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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 incre-
ment 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 types. Using
-debug slows down the process and may be the reason for
a buffer underrun.
kdebug=#, kd=#
Tell the scg-driver to modify the kernel debug value
while SCSI commands are running.
-silent, -s
Do not print out a status report for failed SCSI com-
mands.
-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 com-
mand 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. -V will show
data buffer content in addition. Using -V or -V slows
down the process.
f=file
Specify the filename where the output should be written
or the input should be taken from. Using '-' as
filename will cause readcd to use stdout resp. stdin.
-w Switch to write mode. If this option is not present,
readcd reads from the specified device.
-c2scan
Scans the whole CD or the range specified by the
sectors=range for C2 errors. C2 errors are errors that
are uncorrectable after the second stage of the 24/28 ]
28/32 Reed Solomon correction system at audio level
(2352 bytes sector size). If an audio CD has C2 errors,
interpolation is needed to hide the errors. If a data
CD has C2 errors, these errors are in most cases
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Schily's USER COMANDS READCD(1)
corrected by the EC/EDC code that makes 2352 bytes out
of 2048 data bytes. The EC/EDC code should be able to
correct about 100 C2 error bytes per sector.
If you find C2 errors you may want to reduce the speed
using the speed= option as C2 errors may be a result of
dynamic unbalance on the medium.
-cxscan
Scans the whole CD or the range specified by the
sectors=range for C1/C2/CU errors. In non-verbose
mode, only a summary is printed. With -v, a line for
each non error free second is printed. with -vv, a
line for each second is printed. This scan method only
works for a few drives.
-edc-corr
In this mode, readcd reads CD data sectors in
uncorrected audio mode and then tries to correct the
data using the EC/EDC decoder library from Heiko
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