|READCD(1)||Schily´s USER COMMANDS||READCD(1)|
- display version information for readcd on standard output.
- Print version information and exit.
- Increment the level of general verbosity by one. This is used e.g. to display the progress of the process.
- 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. Note that reading in clone mode results in having no error correction at sub-channel level. Even in the main data channel, there is less error correction than with other read modes. This results in a slightly quality degradation. Avoid copying audio CDs in clone mode for this reason.
- 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.
- 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.
- In this mode, readcd reads CD data sectors in uncorrected audio mode and then tries to correct the data using the ECC/EDC decoder library from Heiko Eissfeldt. As this library implements looping over two layers of error correction, readcd may be able to correct more data than the firmware of the CD-ROM drive. This option is currently experimental and only applicable with CD media and currently only supports plain 2048 Byte CD-ROM sectors.
- 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.
- Output the speed values for meshpoints=# as factor based on single speed of the current medium. This only works if readcd is able to determine the current medium type.
- Retrieve a full TOC from the current disk and print it in hex.
- 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.
- 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 readcd completes, the error recovery mode of the drive is switched back to the remembered old mode.
- Do not abort if the high level error checking in readcd found an uncorrectable error in the data stream.
- Do not truncate the output file when opening it.
- 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.
- Scans the whole DVD or the range specified by the sectors=range for pisum8 errors. In non-verbose mode, only a summary is printed. With -v, a line for each non error free block of 8 * 32 kB is printed. with -vv, a line for each block of 8 * 32 kB is printed. This scan method only works for a few drives.
- Scans the whole DVD or the range specified by the sectors=range for pif errors. In non-verbose mode, only a summary is printed. With -v, a line for each non error free block of 32 kB is printed. with -vv, a line for each block of 32 kB is printed. This scan method only works for a few drives.
- This option modified the behavior for -cxscan, -pi8scan and -pifscan. The output is better suited for gnuplot.
- Set the retry count for high level retries in readcd to #. The default is to do 128 retries which may be too much if you like to read a CD with many unreadable sectors.
- 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.
- 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, readcd 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.
- Switch to write mode. Writing is only possible to DVD-RAM media. For other media, use cdrecord instead. Note that cdrecord also supports to write DVD-RAM media. If this option is not present, readcd reads from the specified device.
- 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
General SCSI addressing
- 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 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.
- 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
- A comma separated list of SCSI options that are handled by libscg. The implemented options may be uptated indepentendly from applications. Currently, one option: ignore-resid is supported to work around a Linux kernel bug.
- -silent, -s
- Do not print out a status report for failed SCSI commands.
- 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.
- 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, readcd 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.
- 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.
readcd 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:
readcd dev=2,0 sectors=150-10000 f=cdimage.raw To write the data from the file cdimage.raw (e.g. a filesystem image from mkisofs) to a DVD-RAM, call:
readcd dev=2,0 -w f=cdimage.raw
- 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.
- 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.
- No error appeared.
- A specific error appeared. This may be a usage error caused by an illegal command line or another error with a problem specific error message from readcd.
- An unspecified error appeared during the process of talking to the drive. See SCSI error message for more informations. The section DIAGNOSTICS below contains an explanation on how to read SCSI error messages.
- It cannot see if a SCSI command could not be sent at all.
- It cannot get the SCSI status byte. Readcd for that reason cannot report failing SCSI commands in some situations.
- It cannot get real DMA count of transfer. Readcd cannot tell you if there is an DMA residual count.
- It cannot get number of bytes valid in auto sense data. Readcd cannot tell you if device transfers no sense data at all.
- It fetches to few data in auto request sense (CCS/SCSI-2/SCSI-3 needs >= 18).
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
Joerg Schilling Seestr. 110 D-13353 Berlin GermanyAdditional information can be found on:
|Version 3.02 2017/06/06||Joerg Schilling|