dvdisaster Version 0.64 (pl2) |
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Command syntaxActions. dvdisaster needs to be called with at least one action specified either in long form (--read) or just by the beginning letter (-r):
Device and filenames. These options do also have a long form (--device) and a first letter abbreviation (-d). They are used to change the pre-selected drive and file names.
Other Options. These less frequently used options are only available in the long form unless noted otherwise.
Actions.--scan [n-m]: Scan medium for read errorsReads every medium sector and prints the number of unreadable sectors when finished. It is possible to limit the scan to a certain range of sectors. Sector counting starts with 0; "end" refers to the last sector. The given interval is inclusive; 0-100 will read 101 sectors. Do not use white space in the abbreviated form between the "-s" and the interval: dvdisaster -s0-100 # reads sectors 0 to 100 dvdisaster --scan 0-100 # long form dvdisaster --scan 3000-end # reads from sector 3000 until the end of medium --read [n-m]: Read the medium image to hard disc Creates a medium image on the hard disc. If the image file is already present, only sectors missing in the image will be re-read. This allows for completing the image in several reading passes, and optionally to employ different drives in each of them. --read will use the linear reading strategy by default. Add the --adaptive-read option to employ the adaptive reading strategy instead. The range of sectors to be read in can be limited analogous to the --scan option. --create: Create the error correction file Creates the error correction file for an image.
Try to fix an image using the error correction file. If not all sectors can be repaired during the first pass, try reading the image again with another --read pass (some hints for re-reading). This might gather enough missing sectors for a successful error correction run.
--test: Test whether image and error correction files match This action simply checks whether the image and error correction files match (e.g. belong to the same medium), and whether their internal check sums are correct. See also topic 3.3 in the Questions and Answers. --unlink: Delete the image file at program exit This function deletes the image file if all preceeding actions were successful.
Devices and file names.--device <drive>: Select a driveThe preset is "/dev/cdrom" for Linux. Under Windows, the first CD/DVD drive (according to the drive letter order) is pre-selected. Linux: dvdisaster supports drives which are accessible through the Linux uniform CD-ROM driver and which are MMC3 compliant. These are particularly ATAPI drives attached to the symbolic devices /dev/hd* and SCSI drives using the symbolic devices /dev/scd*. External drives using other bus systems (like USB, IEEE 1394) usually also appear as SCSI devices. Accessing ATAPI drives using the ide-scsi module is not recommended, but possible since these devices are usually available under the /dev/scd* interface. The general SCSI driver sg (/dev/sg*) is not supported. This should not be a problem since the respective drives are also available using the /dev/scd* or /dev/sr* devices. Windows: dvdisaster supports local drives implementing the MMC3 standard and which are referenced through a drive letter in the system. --prefix <prefix>: Prefix for image and error correction files The preset is "medium"; the image and error correction files will automatically receive the endings ".img" and ".ecc". --image <file name>: Name of image file The preset is "medium.img"; the specified file name will be used exactly (without appending a suffix) for the image file as long as --auto-suffix is not specified also. --eccfile <file name>: Name of error correction file The preset is "medium.ecc"; the specified file name will be used exactly (without appending a suffix) for the error correction file as long as --auto-suffix is not specified also. --list: shows drives available under ASPI This option lists all CD/DVD drives which are accessible through the ASPI layer of Windows:
The default is trying to access a drive using SPTI first and only fall back to ASPI if the former does not work. Usage of the ASPI layer can be forced by specifying the drive by its number rather than by its letter. To read in a disc using ASPI and the "MYDRIVE" unit from the above example, you would therefore enter:
Other Options.--adaptive-read: Use adaptive strategy for reading damaged mediaThis switch selects the adaptive reading strategy which is particularly suited for reading in damaged media. Use this switch in conjunction with -r/--read and with -e/--eccfile. Specifying the error correction file causes the reading process to finish as soon as enough information has been collected for recovering the medium image.
--auto-suffix: automatically add .img and .ecc file suffixes When this option is given, file names specified by the -i/--image- or -e/--eccfile option will be automatically appended with ".img" or ".ecc" respectively if no other file name extension is already present. --cache-size <size in MB>: Specify the cache size dvdisaster optimizes access to the image and error correction files by maintaining its own cache. The cache size can be between 1 and 2048 MB. The preset is 32MB, which should be suitable for most systems. This option is only effective during the --create action. --dao: Assumes "disk at once" medium Media written in "TAO" ("track at once") mode may contain two sectors with pseudo read errors at the end. By default these two errors are ignored by dvdisaster. If you are extremely unlucky to have a "DAO" ("disc at once") medium with exactly one or two real read errors at the end, use the "--dao" option to have these read errors handled correctly. --fill-unreadable <fill byte>: fill unreadable sectors with given byte
dvdisaster marks unreadable sectors with a special filling sequence which is very unlikely
to occur in undamaged media.
-j / --jump <number of sectors>: Skip sectors after a read error This option has slightly different behaviour depending on the used reading strategy:
--parse-udf: Use information from ISO/UDF filesystem dvdisaster will determine the image size from the ISO/UDF file system if this option is given. This works around some problems caused by drives reporting incorrect image lengths with DVD-RW/+RW media. -n / --redundancy: Set error correction code redundancy The redundancy specifies the percentage of correctable errors in the best case. Since the ideal case is rare, it is recommended to apply a reasonable margin to the redundancy. Also, consider the following properties of the error correction:
--speed-warning [n]: Warns when reading speed drops a certain amount Prints a warning when the reading speed changes by more than n percent. This is useful for recognizing a beginning decay in media quality. If the optional value [n] is omitted, a preset of 10 percent is used. --spinup-delay [n]: Gives drive time to spin up
Waits the given amount of seconds for the drive to spin up before the real
reading process starts.
This avoids spurious warnings about speed changes at the beginning of the medium
when the --speed-warning option is used. --split-files: Splits image into files <= 2GB Allows the creation of large images on file systems which are limited to 2GB per file (e.g. FAT from Windows). The image is spread over upto 100 files "medium00.img", "medium01.img" etc. at the cost of a small performance hit. The file name must still be specified as "medium.img" using the --image option; the numbering will be automatically inserted when this switch is active. Error correction files are still limited to 2GB; this will change in one the next versions.
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Copyright 2004,2005 Carsten Gnörlich. Verbatim copying and distribution of this entire article is permitted in any medium, provided this notice is preserved. |
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