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OpenSolaris 2009.06 - man page for readcd (opensolaris section 1)

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

       readcd - read or write data Compact Discs

       readcd [ dev=device ][ options ]

       Readcd is used to read or write Compact Discs.

       The  device refers to scsibus/target/lun of the drive. 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 lat-
       ter 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 implementa-
       tions 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.

       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 scan-
       ning 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=

       To make readcd portable to all UNIX platforms,  the  syntax  dev=  devicename:scsibus,tar-
       get,lun	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.

       Scsibus	0 is the default SCSI bus on the machine. Watch the boot messages for more infor-
       mation 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 cdrecord.

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

	      Print version information and exit.

	      Sets  the  SCSI target for the drive, see notes above.  A typical device specifica-
	      tion is dev=6,0 .  If a filename must be provided together with the numerical  tar-
	      get  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,  cdrecord  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/default/cdrecord (see FILES section).

	      If no dev= option is present, or if the dev= option only contains a transport spec-
	      ifyer 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.

	      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 correspond-
	      ing 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 sec-
	      tor types.  Using -debug slows down the process and may be the reason for a  buffer

       kdebug=#, kd=#
	      Tell  the  scg-driver to modify the kernel debug value while SCSI commands are run-

       -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 readcd to use stdout resp. stdin.

       -w     Switch to write mode. If this option is not present, readcd reads from  the  speci-
	      fied 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.

	      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 EiBfeldt. 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  cur-
	      rently only supports plain 2048 Byte CD-ROM sectors.

	      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.

       -plot  This  option  modified the behavior for -cxscan, -pi8scan and -pifscan.  The output
	      is better suited for gnuplot.

	      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

	      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, repre-
	      senting 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.

       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, 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.

	      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 similar name as with the f= option but the
	      suffix .toc added.

	      Do not abort if the high level error checking  in  readcd  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 readcd 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 readcd to #.  The default is to do
	      128 retries which may be too much if you like to read a  CD  with  many  unreadable

	      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.  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.

	      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

       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:

	   readcd dev=2,0 f=cdimage.raw

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

	   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

       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.

       cdrecord(1), mkisofs(1), scg(7), fbk(7), rcmd(3), ssh(1).

       If  you	don't  want  to  allow	users to become root on your system, readcd may safely be
       installed suid root. This allows all users or a group of users with no root privileges  to
       use readcd.  Readcd in this case will only allow access to CD-ROM type drives- To give all
       user access to use readcd, enter:

	    chown root /usr/local/bin/readcd
	    chmod 4711 /usr/local/bin/readcd

       To give a restricted group of users access to readcd enter:

	    chown root /usr/local/bin/readcd
	    chgrp cdburners /usr/local/bin/readcd
	    chmod 4710 /usr/local/bin/readcd

       and add a group cdburners on your system.

       Never give write permissions for non root users to the /dev/scg?  devices unless you would
       allow anybody to read/write/format all your disks.

       You  should  not connect old drives that do not support disconnect/reconnect to either the
       SCSI bus that is connected to the CD-Recorder or the source disk.

       When using readcd with the broken Linux SCSI generic driver.  You should note that  readcd
       uses  a	hack,  that tries to emulate the functionality of the scg driver.  Unfortunately,
       the sg driver on Linux has several severe bugs:

       o      It cannot see if a SCSI command could not be sent at all.

       o      It cannot get the SCSI status byte.  Readcd for that reason cannot  report  failing
	      SCSI commands in some situations.

       o      It  cannot  get  real DMA count of transfer.  Readcd cannot tell you if there is an
	      DMA residual count.

       o      It cannot get number of bytes valid in auto sense data.  Readcd cannot tell you  if
	      device transfers no sense data at all.

       o      It fetches to few data in auto request sense (CCS/SCSI-2/SCSI-3 needs >= 18).

       A typical error message for a SCSI command looks like:

	      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

       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  usu-
       ally  is:  I/O error unless other problems happen. The next words contain a short descrip-
       tion 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

       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.

       If you want to actively take part on the development of cdrecord, you may join the cdwrit-
       ing mailing list by sending mail to:


       and include the word subscribe in the body.  The mail address of the list is:


       Joerg Schilling
       Seestr. 110
       D-13353 Berlin

       Additional information can be found on:

       If you have support questions, send them to:

       or other-cdwrite@lists.debian.org

       If you have definitely found a bug, send a mail to:

       or joerg.schilling@fokus.fraunhofer.de

       To subscribe, use:

       or http://lists.berlios.de/mailman/listinfo/cdrecord-support

       See attributes(5) for descriptions of the following attributes:

       |Availability	    | SUNWmkcd	      |
       |Interface Stability | Unstable	      |
       This  utility is part of cdrtools.  The source for cdrtools is available on http://openso-

Joerg Schilling 			   Version 2.0					READCD(1)

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