dvdisaster Version 0.72.4 / 0.72 (pl4) | To the Internet version

Contents

News
Overview
Howtos
· | The big picture
· | Scanning media for errors
· | Putting error correction data on a separate file
· | Putting error correction data on the medium
· | Recovering media images
· | Getting information about images and error correction data
| - | Show information
| - | Results for error correction files
| - | Results for augmented images
| - | Examples
· | Testing image compatibility
· | Dialogs and buttons
Download
Questions and Answers
Bug reporting

### Results for images augmented with error correction data

When verifying an image against its embedded error correction data the information will be given with respect to:

- the whole (augmented) image
- the error correction data part:

Output field "Image file summary":

Medium sectors: | The number of sectors in the augmented image (including the sectors added by dvdisaster; one sector = 2KB).
Data checksum: | The MD5 checksum of the original image (prior to augmenting it with error correction data).
Ecc headers: Data section: Crc section: Ecc section: | The augmented image consists of three sections plus some ecc header sectors embedded into them. These values describe how many sectors are unreadable in the respective sections.
If all values in this output field are okay the message "Good image." appears. Otherwise the most important error will be explained there.

Output field "Error correction data":

Created by: | Prints the dvdisaster version which was used for creating the error correction data. Alpha/developer versions are highlighted in red.
Method: | The method and redundancy used for creating the error correction data.
Requires: | Processing the error correction data requires at least the shown version of dvdisaster.

Medium sectors:

The first value is the number of sectors in the augmented image; the second one describes the number of sectors the image had before it was processed with dvdisaster. Since the error correction data is placed behind the user data, the checksum of the original image can be obtained as follows (using the command line of GNU/Linux):
`head -c $((2048*121353)) medium.iso | md5sum`
The first parameter for head is the sector size (2048) multiplied with the original image length (121353). This property of augmented images can also be used to cut off the error correction data:
`head -c $((2048*121353)) medium.iso >stripped_image.iso`

Data checksum: | The MD5 checksum of the original image (see previous explanations).
CRC checksum: ECC checksum: | MD5 checksums of the CRC and ECC sections of the augmented image. These two can not be easily reproduced outside of dvdisaster.
If all values in this output field are okay the message "Good error correction data." appears. Otherwise the most important error will be explained there.

Copyright 2004-2012 Carsten Gnörlich. Verbatim copying and distribution of this entire article is permitted in any medium, provided this notice is preserved.