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DVDISASTER(1)		 protection for	optical	media		 DVDISASTER(1)

       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 me-
       dia 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  re-
	      tried  at	 least n times and at most m times. Recovery of	defec-
	      tive CD media may	improve	when combined with --read-raw.

       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  er-
	      ror correction file corr.ecc.

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

       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 corr.ecc.

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

       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. -r100-200.

       -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 with-
	      out 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 meth-
	      ods.  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

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

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

	      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

	      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 ma-
	      chines 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 upto
	      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  correc-
	      tion  data.   dvdisaster can either use a	generic	encoding algo-
	      rithm using 32bit	or 64bit wide operations running on the	 inte-
	      ger unit of the processor, or use	processor specific extensions.
	      Available	 extensions  are SSE2 for x86 based processors and Al-
	      tiVec 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  se-
	      lected if	the processor supports them and	nothing	else is	speci-
	      fied 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 ad-
	      vantage 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 unreli-
	      able 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 im-
	      age 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:
	      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 older.
	      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

       --prefetch-sectors n
	      number of	sectors	to preload during RS03 de-/encoding  (default:
	      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 sec-
	      tor instead.

       --read-attempts n-m
	      attempts n upto 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:

       --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  <daniel.baumann@pan->, for the Debian project (but may be used by others).
       Since version 0.70 it is	maintained by Carsten Gnoerlich.

0.79.5				  2015-12-16			 DVDISASTER(1)


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