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PROGRAM:

NAME

readom - read or write data Compact Discs

SYNOPSIS

readom dev=device [ options ]

DESCRIPTION

Readom is used to read or write Compact Discs.

The device refers to a device location similar to the one used in the wodim command. Refer
to its manpage for details.

Also note that this version of readom uses a modified libusal library which has a
different behaviour compared to the one distributed by its original author.

OPTIONS

If no options except the dev= option have been specified, readom goes into interactive
mode. Select a primary function 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 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, readom 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/wodim.conf (see FILES section).

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 libusal. 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 usal-driver to modify the kernel debug value while SCSI commands are
running.

-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.

f=file Specify the filename where the output should be written or the input should be
taken from. Using '-' as filename will cause readom to use stdout resp. stdin.

-w Switch to write mode. If this option is not present, readom 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 corrected by the ECC/EDC code that
makes 2352 bytes out of 2048 data bytes. The ECC/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.

-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

sectors=range
Specify a sector range that should be read. The range is specified by the starting
sector number, a minus sign and the ending sector number. The end sector is not
included in the list, so sectors=0-0 will not read anything and may be used to
check for a CD in the drive.

speed=#
Set the speed factor of the read or write process to #. # is an integer,
representing a multiple of the audio speed. This is about 150 KB/s for CD-ROM and
about 172 KB/s for CD-Audio. If no speed option is present, readom will use
maximum speed. Only MMC compliant drives will benefit from this option. The speed
of non MMC drives is not changed.

Using a lower speed may increase the readability of a CD or DVD.

ts=# Set the maximum transfer size for a single SCSI command to #. The syntax for the
ts= option is the same as for wodim fs=# or sdd bs=#.

If no ts= option has been specified, readom defaults to a transfer size of 256 kB.
If libusal 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.

-notrunc
Do not truncate the output file when opening it.

-fulltoc
Retrieve a full TOC from the current disk and print it in hex.

-clone Do a clone read. Read the CD with all sub-channel data and a full TOC. The full
TOC data will be put into a file with similar name as with the f= option but the
suffix .toc added.

-noerror
Do not abort if the high level error checking in readom found an uncorrectable
error in the data stream.

-nocorr
Switch the drive into a mode where it ignores read errors in data sectors that are
a result of uncorrectable ECC/EDC errors before reading. If readom completes, the
error recovery mode of the drive is switched back to the remembered old mode.

retries=#
Set the retry count for high level retries in readom to #. The default is to do
128 retries which may be too much if you like to read a CD with many unreadable
sectors.

-overhead
Meter the SCSI command overhead time. This is done by executing several commands
1000 times and printing the total time used. If you divide the displayed times by
1000, you get the average overhead time for a single command.

meshpoints=#
Print read-speed at # locations. The purpose of this option is to create a list of
read speed values suitable for e.g. gnuplot. The speed values are calculated
assuming that 1000 bytes are one kilobyte as documented in the SCSI standard. The
output data created for this purpose is written to stdout.

-factor
Output the speed values for meshpoints=# as factor based on single speed of the
current medium. This only works if readom is able to determine the current medium
type.

EXAMPLES

For all examples below, it will be assumed that the drive is connected to the primary SCSI
bus of the machine. The SCSI target id is set to 2.

To read the complete media from a CD-ROM writing the data to the file cdimage.raw:

readom dev=2,0 f=cdimage.raw

To read sectors from range 150 ... 10000 from a CD-ROM writing the data to the file
cdimage.raw:

readom dev=2,0 sectors=150-10000 f=cdimage.raw

To write the data from the file cdimage.raw (e.g. a filesystem image from genisoimage) to
a DVD-RAM, call:

readom dev=2,0 -w f=cdimage.raw

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 wodim to create a pipe to the rsh(1) program and disallows
wodim 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.

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