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
     corect     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 referres to exactly one SCSI device, a  short-
     hand  in the form dev= devicename:@ or dev= devicename:@,lun
     may be used instead of dev= devicename:scsibus,target,


     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.


     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 intercative mode.  Select a primary func-
     tion and then follow the instructions.

     -version
          Print version information and exit.

     -v    Increment the level of general verbosity by one.
     -V    Increment the verbose level in respect of SCSI command
          transport  by one.  This helps to debug problems during
          the writing process, that occur in the drive.   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 and may be the reason for a  buffer  under-
          run.

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

     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.

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:

         readcd dev=2,0 f=cdimage.raw

     To read sectors from range 150 ... 10000 from a CD-ROM writ-
     ing 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 filesys-
     tem image from mkisofs) to a DVD-RAM, call:

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

FILES

SEE ALSO

     cdrecord(1), mkisofs(1), scg(7), fbk(7).

NOTES

     If you don't want to allow users to become root on your sys-
     tem,  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 con-
     nected 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 emu-
     late 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  can-
          not 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).

DIAGNOSTICS

     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)

     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 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 avail-
     able,  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 replace-
     able 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.

BUGS

CREDITS

MAILING LISTS

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

          other-cdwrite-request@lists.debian.org

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

          cdwrite@lists.debian.org

AUTHOR

     Joerg Schilling
     Seestr. 110
     D-13353 Berlin
     Germany

     Additional information can be found on:
     http://www.fokus.gmd.de/usr/schilling/cdrecord.html

     Mail bugs and suggestions to:

     joerg@schily.isdn.cs.tu-berlin.de or  js@cs.tu-berlin.de  or
     schilling@fokus.gmd.de