ADF vs SCP read errors nDOS and bad sectors

[wvos]

The 'wave' in the flux data can only be caused by the rotational speed of the disk.  Typically, this is almost always due to the drive itself and not the disk, but a disk with clumps of debris can cause this as well.  You might want to change USB cables or ports to see if that makes a difference for powering the drive (unless you are using an external power source, in which case it is just flat bad).  You could also try a different drive as well.  Don't forget that you should be cleaning the disk heads every time you read a disk.

I checked with a "good" disk : ( https://www.dropbox.com/s/jldis8xbciiys8...9.png?dl=0 ) 



So I think the speed variation is caused by the fact that the paper ring inside the casing is still dirty, as I can't clean that. But I switched to use a new casing to keep friction to a minimum. The disk is powered by a USB2 (no charge), but I changed that for a separate PC power supply. That should further stabilize the speed.

I found that when the software starts to hesitate ( re-reads ) that, even though it eventually returns green and continues, the track is often still bad. 
For example in this ADF the file TEST1 fails on track79. Salvage shows me this when I try salvage it:



So that seems to support your thinking that the block links got corrupted. 

If you're interested this is the adf: https://www.dropbox.com/s/mivo0kgh4o9nxk...s.rar?dl=0