dvdisaster Version 0.63
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Contents

Overview
Examples and screen shots
Download
Command line mode
·Using the command line
·Creating a medium image
·Generating error correction files
·Scanning the medium for errors
·Recovering a medium image
·Choosing alternative drives and file names
·Performing several actions within one program call
·Hints for storing the error correction files
·Command syntax
Questions and Answers
Imprint

Recovering a medium image

To recover data from damaged media, you must first try to read as much data as possible from it into an image file.
If you add the --adaptive-read option and point dvdisaster to the name of the error correction file, reading will stop when enough data for recovering the image has been collected - resulting in a major time saving!

user@linux> dvdisaster -r --adaptive-read -e medium.ecc
dvdisaster-0.63 Copyright 2004,2005 Carsten Gnoerlich.
[... remainder of the GPL announcement ...]

Device: /dev/cdrom,  ATAPI DVD+RW 8X4X12 B2K7
Medium: DVD+R, 2224288 sectors, 1 layer(s)

Adaptive reading: Trying to collect enough data for error correction.
Creating new medium.img image.
Repairable: 2.6% (correctable: 0; now reading [0..2224288], size 2224288)
Sectors 57264-57279: Medium Error; Unrecovered read error.
Filling image area [57280..1083504]
[... more descriptions of reading process ...]
Repairable: 100.0% (correctable: 319200; now reading [320304..327065], size 6762)
Sufficient data for reconstructing the image is available.

Then you need the appropriate error correction file, which you have hopefully generated at a time when the medium was still fully readable. Enter:

user@linux> dvdisaster -f
dvdisaster-0.63 Copyright 2004,2005 Carsten Gnoerlich.
[... remainder of the GPL announcement ...]

Opening medium.img: 2224288 medium sectors.

Fix mode: Repairable sectors will be fixed in the image.
    5 repaired sectors: 708225 59850 69825 79800 199500
    6 repaired sectors: 708226 59851 69826 79801 89776 199501
[... more reports on repaired sectors ...]
    5 repaired sectors: 708224 59849 69824 79799 199499
Ecc progress: 100.0%
Repaired sectors: 33264
Good! All sectors are repaired.
Erasure counts per ecc block: avg = 3.3; worst = 7.

The message "Good! All sectors are repaired." confirms that the medium image ("medium.img") has been fully recovered. The image can be written to a new medium using a suitable CD/DVD recording software. If you need to specify the image format, select ". i s o".

If uncorrectable sectors remain after this stage, enter "dvdisaster -r" again. dvdisaster will try to re-read the missing sectors, and this might retrieve enough missing sectors for another successful "dvdisaster -f" run.
Re-reading the medium on another drive might also be worthwhile as well as performing the second read attempt at the next morning: Some drives read better while being cold.

Copyright 2004,2005 Carsten Gnörlich.
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