Provided by: dvdisaster_0.79.5-9_amd64 bug


       DVDISASTER - data loss/scratch/aging protection for optical media


       dvdisaster  [-r|-c|-f|-s|-t[q]|-u]  [-d  device]  [-p  prefix] [-i image] [-e eccfile] [-o
       file|image] [-a method-list] [-j n] [-n n%] [-m n] [-v] [-x n] [--adaptive-read]  [--auto-
       suffix]  [--cache-size n] [--dao] [--defective-dump d] [--driver d] [--eject] [--encoding-
       algorithm  n]  [--encoding-io-strategy  n]  [--fill-unreadable  n]  [--ignore-fatal-sense]
       [--ignore-iso-size]  [--internal-rereads n] [--medium-info] [--old-ds-marker] [--prefetch-
       sectors  n]  [--raw-mode  n]  [--read-attempts   n-m]   [--read-medium   n]   [--read-raw]
       [--resource-file n] [--speed-warning n] [--spinup-delay n]


       DVDISASTER  provides  a  margin  of  safety  against  data loss on optical media caused by
       scratches or aging media. It creates error  correction  data  which  is  used  to  recover
       unreadable sectors if the disc becomes damaged at a later time.


       dvdisaster -d /dev/hdc -s
              Scans the medium in drive /dev/hdc for errors.

       dvdisaster -d /dev/hdc -i medium.iso -r
              Reads an image from drive /dev/hdc into the file medium.iso.

       dvdisaster -d /dev/hdc -i medium.iso --read-raw -r
              Creates  an  image as described above. Each sector's integrity is verified by using
              its EDC and L-EC raw data. Only possible for CD  media;  otherwise  the  --read-raw
              option is silently ignored.

       dvdisaster -d /dev/hdc -i medium.iso --read-attempts n-m -r
              Creates an image as described above. Defective sectors are retried at least n times
              and at most m times. Recovery of defective CD media may improve when combined  with

       dvdisaster -d /dev/hdc -i medium.iso -e corr.ecc -r --adaptive-read
              Uses  the  adaptive  reading strategy to read an image from drive /dev/hdc into the
              file medium.iso.  Reading will stop when enough data has been  gathered  to  repair
              the image using the error correction file corr.ecc.

       dvdisaster -i medium.iso -e corr.ecc -c
              Creates an error correction file corr.ecc for the image medium.iso.

       dvdisaster -i medium.iso -mRS02 -n 350000 -c
              Augments  the  image  medium.iso  with  error correction information, expanding the
              image to no more than 350000 sectors. If -n is omitted the image will  be  expanded
              to  the  smallest  possible  medium  size  (CD, DVD, DVD9).  Note the missing blank
              between -m and RS02.

       dvdisaster -i medium.iso -e corr.ecc -f
              Repairs the image file medium.iso using the error correction file corr.ecc.

       dvdisaster -i medium.iso -e corr.ecc -t
              Verifies the image medium.iso with  information  from  the  error  correction  file

       NOTE:  Omit  the  -e  corr.ecc  options when working with augmented images in the examples


       Action selection (at least one action must be specified):

       -r, --read
              Read the medium image to hard disc. Use -rn-m to read a certain sector range,  e.g.

       -c, --create
              Create .ecc information for the medium image.

       -f, --fix
              Try to fix medium image using .ecc information.

       -s, --scan
              Scan the medium for read errors.

       -t, --test, -tq, --test=q
              Test  integrity  of  the  .iso  and  .ecc files. When the "q" option is given, only
              information is output which can be gathered without fully scanning the files.

       -u, --unlink
              Delete .iso files (when other actions complete).

       Drive and file specification:

       -d, --device device
              read from given device (default: /dev/cdrom).

       -p, --prefix prefix
              prefix of .iso/.ecc file (default: medium.* ).

       -i, --image imagefile
              name of image file (default: medium.iso).

       -e, --ecc eccfile
              name of parity file (default: medium.ecc).

       -o, --ecc-target file|image
              Specifies whether RS03 should create error correction  files  or  augmented  images
              (default: image).

       Tweaking options (see manual before using!):

       -a, --assume method1,method2,...
              Assumes that the image is augmented with one of the given methods.  This enables an
              exhaustive search for method signatures and might be helpful  for  detecting  error
              correction  information  on  damaged  media.  If  the  image  does  not contain the
              specified error correction information, a significant amount of CPU  and  I/O  time
              may be wasted.
              Possible values are RS02 and RS03.

       -j, --jump n
              jump n sectors forward after a read error (default: 16).

       -n, --redundancy n[unit]
              Error correction data redundancy. Allowed values depend on the method:

              RS01- and RS03-error correction files
                     -n x  creates error correction file with x roots.
                     -n x% creates error correction file with x percent redundancy.
                     -n xm creates error correction file of approx. x MiB size.

              RS01 error correction flles additionally support:
                     -n normal - optimized codec for 14.3% redundancy/32 roots.
                     -n high   - optimized codec for 33.5% redundancy/64 roots.

              RS02 images:
                     -n CD   augments image suitable for CD media.
                     -n DVD  augments image suitable for DVD media.
                     -n DVD9 augments image suitable for DVD9 media.
                     -n BD   augments image suitable for BD media.
                     -n BD2  augments image suitable for two layered BD media.
                     -n x    augments image using approx. x sectors in total.
                     -n x%   augments image with approx. x% redundancy.
                     -n xr   augments image with x roots error correction data.

              RS03 images:
                     Setting  the  redundancy  is  not possible due to constraints in the format.
                     The codec will automatically choose the size of the smallest fitting medium.

       -m, --method n
              lists/selects error correction methods (default: RS01).
              Possible values are RS01 and RS02.

       -v, --verbose n%
              more diagnostic messages

       -x, --threads n
              Use n threads for encoding with the RS03 method. Use 2 or 4 threads for 2 or 4 core
              processors  respectively.   On larger machines save one core for housekeeping; e.g.
              use 7 threads on an eight core machine.

              use optimized strategy for reading damaged media.

              automatically add .iso and .ecc file suffixes.

       --cache-size n
              image cache size in MiB during -c mode (default: 32MiB).

       --dao  assume DAO disc; do not trim image end.

       --defective-dump d
              Specifies the sub directory for storing incomplete raw sectors.

       --driver d (Linux only)
              Selects between the sg  (SG_IO)  driver  (default  setting)  and  the  older  cdrom
              (CDROM_SEND_PACKET)  driver  for accessing the optical drives.  Both drivers should
              work equally well; however the cdrom driver is known to cause  system  failures  on
              some  ancient  SCSI  controllers.  The older cdrom driver was the default up to and
              including dvdisaster 0.72.x; if the now pre-selected sg driver changes something to
              the worse for you please switch back to the older driver using --driver=cdrom.

              eject medium after successful read.

       --encoding-algorithm [32bit|64bit|SSE2|AltiVec]
              This option affects the speed of generating RS03 error correction data.  dvdisaster
              can either use a generic encoding algorithm using 32bit or  64bit  wide  operations
              running on the integer unit of the processor, or use processor specific extensions.
              Available  extensions  are  SSE2  for  x86  based processors and AltiVec on PowerPC
              processors. These extensions encode with 128bit wide operations  and  will  usually
              provide   the   fastest   encoding   variant.   The  SSE2/AltiVec  algorithms  will
              automatically be selected if the  processor  supports  them  and  nothing  else  is
              specified by this option.

       --encoding-io-strategy [readwrite|mmap]
              This  option  controls  how  dvdisaster  performs its disk I/O while creating error
              correction data with RS03. Try both options and see which  performs  best  on  your
              hardware setting.
              The  "readwrite"  option  activates  dvdisaster's own I/O scheduler which reads and
              writes image data using normal file I/O. The  advantage  of  this  scheme  is  that
              dvdisaster  knows  exactly  which  data  needs  to  be  cached  and  preloaded; the
              disadvantage  is  that  all  data  needs  to  be  copied  between  the  kernel  and
              dvdisaster's  own buffers. Usually, this I/O scheme works best on slow storage with
              high latency and seek times; e.g. on all storage involving spinning platters.   The
              "mmap"  option  uses  the  kernel's  memory mapping scheme for direct access to the
              image file. This has the advantage  of  minimal  overhead,  but  may  be  adversely
              affected  by  poor  caching  and preloading decisions made by the kernel (since the
              kernel does not know what dvdisaster is going to do with  the  data).  This  scheme
              performs  well when encoding in a RAM-based file system (such as /dev/shm on Linux)
              and on very fast media with low latency such as SSDs.

       --fill-unreadable n
              fill unreadable sectors with byte n

              continue reading after potentially fatal error condition.

              By default getting the image size from the ISO/UDF  filesystem  is  preferred  over
              querying the drive as most drives report unreliable values.
              However  in  some  rare  cases the image size recorded in the ISO/UDF filesystem is
              wrong. Some Linux live CDs may have this problem.  If you read back the  ISO  image
              from  such CDs and its md5sum does not match the advertised one, try re-reading the
              image with this option turned on.
              Do not blindly turn this option on as it will most likely  create  sub  optimal  or
              corrupted  ISO images, especially if you plan to use the image for error correction
              data generation.

       --internal-rereads n
              internal read attempts for defective CD media sectors (default: -1)
              The drive firmware usually retries unreadable sectors a few times before giving  up
              and  returning  a read error. It is more efficient to set this to 0 or 1 and manage
              read attempts through  the  --read-attempts  parameter.  Most  drives  ignore  this
              setting anyways. Use -1 to leave the drive at its default setting.

              Prints information about the currently inserted medium.

              Marks  missing  sectors  in  a  manner  which is compatible with dvdisaster 0.70 or
              The default marking method is recommended for dvdisaster 0.72 and  later  versions.
              However  images  marked  with  the  current  method can not be processed with older
              dvdisaster versions as missing sectors would not be recognized in the image.

              Do not process the same image with different settings for this option.

       --prefetch-sectors n
              number of sectors to preload during RS03 de-/encoding (default: 32)
              Using a value of n uses approx. n MiB of RAM.

       --raw-mode n
              selects raw reading mode for CD media (default: 20)
              The recommended mode is  20,  which  makes  the  drive  apply  its  built-in  error
              correction  to  the  best  possible  extent before transferring a defective sector.
              However some drives can only read defective sectors using  mode  21,  skipping  the
              last  stage  of  the internal error correction and returning the uncorrected sector

       --read-attempts n-m
              attempts n up to m reads of a defective sector.

       --read-medium n
              read the whole medium up to n times.

              performs read in raw mode if possible.

       --resource-file n
              Specifies the path to the configuration file (default: $HOME/.dvdisaster)

       --speed-warning n
              print warning if speed changes by more than n percent.

       --spinup-delay n
              wait n seconds for drive to spin up.


       Documentation   DVDISASTER   is   documented   by   its   own   manual,    installed    in


       DVDISASTER was written by Carsten Gnoerlich <>.

       This  manual page was written by Daniel Baumann <>, for
       the Debian project (but may be used by others). Since version 0.70  it  is  maintained  by
       Carsten Gnoerlich.