1DVDISASTER(1) protection for optical media DVDISASTER(1)
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6 DVDISASTER - data loss/scratch/aging protection for optical media
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10 dvdisaster [-r|-c|-f|-s|-t[q]|-u] [-d device] [-p prefix] [-i image]
11 [-e eccfile] [-o file|image] [-a method-list] [-j n] [-n n%] [-m n]
12 [-v] [-x n] [--adaptive-read] [--auto-suffix] [--cache-size n] [--dao]
13 [--defective-dump d] [--driver d] [--eject] [--encoding-algorithm n]
14 [--encoding-io-strategy n] [--fill-unreadable n] [--ignore-fatal-sense]
15 [--ignore-iso-size] [--internal-rereads n] [--medium-info] [--old-ds-
16 marker] [--prefetch-sectors n] [--raw-mode n] [--read-attempts n-m]
17 [--read-medium n] [--read-raw] [--resource-file n] [--speed-warning n]
18 [--spinup-delay n]
19
22 DVDISASTER provides a margin of safety against data loss on optical
23 media caused by scratches or aging media. It creates error correction
24 data which is used to recover unreadable sectors if the disc becomes
25 damaged at a later time.
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29 dvdisaster -d /dev/hdc -s
30 Scans the medium in drive /dev/hdc for errors.
31 dvdisaster -d /dev/hdc -i medium.iso -r
33 Reads an image from drive /dev/hdc into the file medium.iso.
34 dvdisaster -d /dev/hdc -i medium.iso --read-raw -r
36 Creates an image as described above. Each sector's integrity is
37 verified by using its EDC and L-EC raw data. Only possible for
38 CD media; otherwise the --read-raw option is silently ignored.
39 dvdisaster -d /dev/hdc -i medium.iso --read-attempts n-m -r
41 Creates an image as described above. Defective sectors are
42 retried at least n times and at most m times. Recovery of defec‐
43 tive CD media may improve when combined with --read-raw.
44 dvdisaster -d /dev/hdc -i medium.iso -e corr.ecc -r --adaptive-read
46 Uses the adaptive reading strategy to read an image from drive
47 /dev/hdc into the file medium.iso. Reading will stop when
48 enough data has been gathered to repair the image using the
49 error correction file corr.ecc.
50 dvdisaster -i medium.iso -e corr.ecc -c
52 Creates an error correction file corr.ecc for the image
53 medium.iso.
54 dvdisaster -i medium.iso -mRS02 -n 350000 -c
56 Augments the image medium.iso with error correction information,
57 expanding the image to no more than 350000 sectors. If -n is
58 omitted the image will be expanded to the smallest possible
59 medium size (CD, DVD, DVD9). Note the missing blank between -m
60 and RS02.
61 dvdisaster -i medium.iso -e corr.ecc -f
63 Repairs the image file medium.iso using the error correction
64 file corr.ecc.
65 dvdisaster -i medium.iso -e corr.ecc -t
67 Verifies the image medium.iso with information from the error
68 correction file corr.ecc.
69 NOTE: Omit the -e corr.ecc options when working with augmented images
71 in the examples above.
72
75 Action selection (at least one action must be specified):
76 -r, --read
78 Read the medium image to hard disc. Use -rn-m to read a certain
79 sector range, e.g. -r100-200.
80 -c, --create
82 Create .ecc information for the medium image.
83 -f, --fix
85 Try to fix medium image using .ecc information.
86 -s, --scan
88 Scan the medium for read errors.
89 -t, --test, -tq, --test=q
91 Test integrity of the .iso and .ecc files. When the "q" option
92 is given, only information is output which can be gathered with‐
93 out fully scanning the files.
94 -u, --unlink
96 Delete .iso files (when other actions complete).
97 Drive and file specification:
99 -d, --device device
101 read from given device (default: /dev/cdrom).
102 -p, --prefix prefix
104 prefix of .iso/.ecc file (default: medium.* ).
105 -i, --image imagefile
107 name of image file (default: medium.iso).
108 -e, --ecc eccfile
110 name of parity file (default: medium.ecc).
111 -o, --ecc-target file|image
113 Specifies whether RS03 should create error correction files or
114 augmented images (default: image).
115 Tweaking options (see manual before using!):
118 -a, --assume method1,method2,...
120 Assumes that the image is augmented with one of the given meth‐
121 ods. This enables an exhaustive search for method signatures
122 and might be helpful for detecting error correction information
123 on damaged media. If the image does not contain the specified
124 error correction information, a significant amount of CPU and
125 I/O time may be wasted.
126 Possible values are RS02 and RS03.
127 -j, --jump n
129 jump n sectors forward after a read error (default: 16).
130 -n, --redundancy n[unit]
132 Error correction data redundancy. Allowed values depend on the
133 method:
134 RS01- and RS03-error correction files
136 -n x creates error correction file with x roots.
137 -n x% creates error correction file with x percent redun‐
138 dancy.
139 -n xm creates error correction file of approx. x MiB
140 size.
141 RS01 error correction flles additionally support:
143 -n normal - optimized codec for 14.3% redundancy/32
144 roots.
145 -n high - optimized codec for 33.5% redundancy/64
146 roots.
147 RS02 images:
149 -n CD augments image suitable for CD media.
150 -n DVD augments image suitable for DVD media.
151 -n DVD9 augments image suitable for DVD9 media.
152 -n BD augments image suitable for BD media.
153 -n BD2 augments image suitable for two layered BD media.
154 -n x augments image using approx. x sectors in total.
155 -n x% augments image with approx. x% redundancy.
156 -n xr augments image with x roots error correction
157 data.
158 RS03 images:
160 Setting the redundancy is not possible due to constraints
161 in the format. The codec will automatically choose the
162 size of the smallest fitting medium.
163 -m, --method n
166 lists/selects error correction methods (default: RS01).
167 Possible values are RS01 and RS02.
168 -v, --verbose n%
170 more diagnostic messages
171 -x, --threads n
173 Use n threads for encoding with the RS03 method. Use 2 or 4
174 threads for 2 or 4 core processors respectively. On larger
175 machines save one core for housekeeping; e.g. use 7 threads on
176 an eight core machine.
177 --adaptive-read
179 use optimized strategy for reading damaged media.
180 --auto-suffix
182 automatically add .iso and .ecc file suffixes.
183 --cache-size n
185 image cache size in MiB during -c mode (default: 32MiB).
186 --dao assume DAO disc; do not trim image end.
188 --defective-dump d
190 Specifies the sub directory for storing incomplete raw sectors.
191 --driver d (Linux only)
193 Selects between the sg (SG_IO) driver (default setting) and the
194 older cdrom (CDROM_SEND_PACKET) driver for accessing the optical
195 drives. Both drivers should work equally well; however the
196 cdrom driver is known to cause system failures on some ancient
197 SCSI controllers. The older cdrom driver was the default upto
198 and including dvdisaster 0.72.x; if the now pre-selected sg
199 driver changes something to the worse for you please switch back
200 to the older driver using --driver=cdrom.
201 --eject
203 eject medium after successful read.
204 --encoding-algorithm [32bit|64bit|SSE2|AltiVec]
206 This option affects the speed of generating RS03 error correc‐
207 tion data. dvdisaster can either use a generic encoding algo‐
208 rithm using 32bit or 64bit wide operations running on the inte‐
209 ger unit of the processor, or use processor specific extensions.
210 Available extensions are SSE2 for x86 based processors and
211 AltiVec on PowerPC processors. These extensions encode with
212 128bit wide operations and will usually provide the fastest
213 encoding variant. The SSE2/AltiVec algorithms will automatically
214 be selected if the processor supports them and nothing else is
215 specified by this option.
216 --encoding-io-strategy [readwrite|mmap]
218 This option controls how dvdisaster performs its disk I/O while
219 creating error correction data with RS03. Try both options and
220 see which performs best on your hardware setting.
221 The "readwrite" option activates dvdisaster's own I/O scheduler
222 which reads and writes image data using normal file I/O. The
223 advantage of this scheme is that dvdisaster knows exactly which
224 data needs to be cached and preloaded; the disadvantage is that
225 all data needs to be copied between the kernel and dvdisaster's
226 own buffers. Usually, this I/O scheme works best on slow storage
227 with high latency and seek times; e.g. on all storage involving
228 spinning platters. The "mmap" option uses the kernel's memory
229 mapping scheme for direct access to the image file. This has the
230 advantage of minimal overhead, but may be adversely affected by
231 poor caching and preloading decisions made by the kernel (since
232 the kernel does not know what dvdisaster is going to do with the
233 data). This scheme performs well when encoding in a RAM-based
234 file system (such as /dev/shm on Linux) and on very fast media
235 with low latency such as SSDs.
236 --fill-unreadable n
238 fill unreadable sectors with byte n
239 --ignore-fatal-sense
241 continue reading after potentially fatal error condition.
242 --ignore-iso-size
244 By default getting the image size from the ISO/UDF filesystem is
245 preferred over querying the drive as most drives report unreli‐
246 able values.
247 However in some rare cases the image size recorded in the
248 ISO/UDF filesystem is wrong. Some Linux live CDs may have this
249 problem. If you read back the ISO image from such CDs and its
250 md5sum does not match the advertised one, try re-reading the
251 image with this option turned on.
252 Do not blindly turn this option on as it will most likely create
253 sub optimal or corrupted ISO images, especially if you plan to
254 use the image for error correction data generation.
255 --internal-rereads n
257 internal read attempts for defective CD media sectors (default:
258 -1)
259 The drive firmware usually retries unreadable sectors a few
260 times before giving up and returning a read error. It is more
261 efficient to set this to 0 or 1 and manage read attempts through
262 the --read-attempts parameter. Most drives ignore this setting
263 anyways. Use -1 to leave the drive at its default setting.
264 --medium-info
266 Prints information about the currently inserted medium.
267 --old-ds-marker
269 Marks missing sectors in a manner which is compatible with
270 dvdisaster 0.70 or older.
271 The default marking method is recommended for dvdisaster 0.72
272 and later versions. However images marked with the current
273 method can not be processed with older dvdisaster versions as
274 missing sectors would not be recognized in the image.
275 Do not process the same image with different settings for this
277 option.
278 --prefetch-sectors n
280 number of sectors to preload during RS03 de-/encoding (default:
281 32)
282 Using a value of n uses approx. n MiB of RAM.
283 --raw-mode n
285 selects raw reading mode for CD media (default: 20)
286 The recommended mode is 20, which makes the drive apply its
287 built-in error correction to the best possible extent before
288 transferring a defective sector. However some drives can only
289 read defective sectors using mode 21, skipping the last stage of
290 the internal error correction and returning the uncorrected sec‐
291 tor instead.
292 --read-attempts n-m
294 attempts n upto m reads of a defective sector.
295 --read-medium n
297 read the whole medium up to n times.
298 --read-raw
300 performs read in raw mode if possible.
301 --resource-file n
303 Specifies the path to the configuration file (default:
304 $HOME/.dvdisaster)
305 --speed-warning n
307 print warning if speed changes by more than n percent.
308 --spinup-delay n
310 wait n seconds for drive to spin up.
311
313 Documentation DVDISASTER is documented by its own manual, installed in
314 /usr/share/doc/dvdisaster/html
315
318 DVDISASTER was written by Carsten Gnoerlich <carsten@dvdisaster.com>.
319 This manual page was written by Daniel Baumann <daniel.baumann@pan‐
321 thera-systems.net>, for the Debian project (but may be used by others).
322 Since version 0.70 it is maintained by Carsten Gnoerlich.
3230.79.5 2015-12-16 DVDISASTER(1)