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READOM(1)		    Schily's USER COMMANDS		     READOM(1)

       readom - read or write data Compact Discs

       readom dev=device [ options ]

       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.

       If no options except the dev= option have been specified,  readom  goes
       into  interactive  mode.	 Select a primary function and then follow the

	      Print version information and exit.

	      Sets the SCSI target for the drive, see notes above.  A  typical
	      device  specification  is	 dev=6,0 .  If a filename must be pro-
	      vided 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 differ-
	      ent 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 charac-
	      ters ',', '/', '@' or ':', it is interpreted as  an  label  name
	      that  may	 be  found in the file /etc/wodim.conf (see FILES sec-

	      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	 time-
	      out, 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 bet-
	      ter 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  rea-
	      son 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 trans-
	      port 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.

	      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.

	      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 com-
	      puted by: bus * 100 + target

	      Specify a sector range that should be read.  The range is speci-
	      fied  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, 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 trans-
	      fer size of 256 kB. If libusal gets lower values from the	 oper-
	      ating  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.

	      Do not truncate the output file when opening it.

	      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	 simi-
	      lar name as with the f= option but the suffix .toc added.

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

	      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.

	      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.

	      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.

	      Print read-speed at # locations.	The purpose of this option  is
	      to  create  a  list of read speed values suitable for e.g.  gnu-
	      plot.  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.

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

       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

	   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

       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

	      Note  that this forces wodim to create a pipe to the rsh(1) pro-
	      gram and disallows wodim to directly access the  network	socket
	      to  the  remote server.  This makes it impossible to set up per-
	      formance 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.

       wodim(1), genisoimage(1), rcmd(3), ssh(1).

       Unless you want to risk getting problems, readom should be run as root.
       If you don't want to allow users to become root on your system,	readom
       may  safely be installed suid root.  For more information see the addi-
       tional notes of your  system/program  distribution  or  README.suidroot
       which is part of the Cdrkit source.

       Documentation  of  the  wodim  program  contains more technical details
       which could also apply to readom.

       A typical error message for a SCSI command looks like:

	      readom: 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 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

       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, fol-
       lowed 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 cur-
       rent command, the text deferred error is appended.

       The sixth line is the error text for the sense code and the sense qual-
       ifier 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

       The eight line reports the timeout set up for this command and the time
       that the command really needed to complete.

       The readom program described here is the Cdrkit spinoff from the origi-
       nal readcd application (see AUTHOR section for details). It may contain
       bugs not present in the original implementation.

       It is definitely less portable than the original implementation.

       For platform specific bugs, see the corresponding README.platform  file
       in the Cdrkit documentation (eg. README.linux).

       If you want to actively take part on the development of readom, you may
       join the developer mailing list via this URL:


       The mail address of the list is: debburn-devel@lists.alioth.debian.org

       Joerg Schilling
       Seestr. 110
       D-13353 Berlin

       This is application is a spinoff from the  original  implementation  of
       readcd	delivered  in  the  cdrtools  package  [1]  created  by	 Joerg
       Schilling, who deserves the most credits for its success.  However,  he
       is  not	involved into the development of this spinoff and therefore he
       shall not be made responsible for any problem caused by it. Do not  try
       to get support from the original author!

       Additional information can be found on:

       If you have support questions, send them to


       If you have definitely found a bug, send a mail to this list or to


       writing	at  least  a  short description into the Subject and "Package:
       cdrkit" into the first line of the mail body.

       [1] Cdrtools 2.01.01a08 from May 2006, http://cdrecord.berlios.de

Joerg Schilling			  Version 2.0			     READOM(1)