Re: unable to read some of a DVD contents
Thanks for the comprehensive explanation,
> > what is the indicator that the burn process was only 95% completed?
> The only reliable indicator seems to be checkreading
> by all drives which shall be able to read the DVD.
> This would mean either
> - to compare each file on the DVD with its original
> on hard disk (if the files on disk did not change
This is the method we used (comparing each file on the DVD with its orginal
on hard drive by using 'cmp' command)
> - or to compare the data image on DVD with the data
> image on disk (if the image was stored on disk)
> - or to compare the data image on DVD with a checksum
> which was made when that image was written to DVD.
> (I prefer this method.)
First time heard about this method. How to actually obtain the DVD checksum?
Will this method run faster than the first one? (We normally have around
10000 files to compare).
Brief explanation on this method will be appreciated (keen to try this out).
> I just had to trash a previously used DVD-RW which
> failed to pass the checksum test with errors at the
> very start of the image. After a test re-write it
> failed to deliver the last 2 MB (but the start of the
> test image was ok). A third re-write yielded missing
> 300 MB at the end of the media.
How did you know there was 300MB data missing at the end of media?
In our case, the file sizes exactly match the file sizes on the harddrive.
> The fourth try failed with
> :-[ PERFORM OPC failed with SK=3h/ASC=73h/ACQ=03h]: Input/output error
> According to keys.txt :
> 3 73 03 POWER CALIBRATION AREA ERROR
> (Not much idea what that means but it looks ugly and fatal)
Got this problem before upgrading growisofs.
> I successfully tested another DVD-RW from the same
> spindle as the ill one. So the burner is not to blame.
> It is not about the manufacturer of the media, not even
> about the particular lot. It is not about the number of
> re-uses. The sucessfull DVD-RW is in heavy test use, has
> a nice collection of scratches ... and it works fine.
> The ill one had its third or fourth re-use, looks shiny
> and smooth ...
> Have a nice day :)