Re: [Bug-ddrescue] Verify recovered data

[Antonio Diaz Diaz]

Reon Toerien wrote:
> When working via USB ports results can be unreliable, nature of the beast.

Not only USB ports. :-(

I have been doing intensive testing with the next version of ddrescue 
and have discovered a SATA CD/DVD drive with the same problem.

I was trying to get a correct copy from two damaged CDs. I tried three 
times with different settings, but the drive always returns wrong data 
without signaling an error for at least one sector. The wrong data 
returned coincides with the data of some nearby good sector, so I guess 
the drive is returning the data from a previous read.

I tried the same two CDs on another computer (with an older IDE driver), 
and ddrescue got the correct image at the first try.