Re: [Bug-ddrescue] Bug in cygwin version 1.21 of ddrescue and a proposition to differentiate errors

[Antonio Diaz Diaz]

Joe Kickman wrote:
> 2. Is it possible to differentiate read errors and add an option to
> wait for the source drive to become ready again? For example, copying
> 160 Gb from a badly damaged seagate drive often caused freezes. It
> helped to power cycle the drive and resume copying from a little bit
> further position [+ or -]6000 LBA. So, an option to
> --wait-ready<seconds_until_exit>  or so together with -K<skip-size>
> would be very helpful:

Ddrescue can't differentiate read errors from a "drive not ready" 
condition, nor can it know if the drive has become ready again unless it 
returns data, but it can wait after each read error with --pause-on-error:

'--pause-on-error=INTERVAL'
     Time to wait after each read error or slow read. Defaults to 0.
     INTERVAL is formatted as in the option '--timeout' above. If
     INTERVAL begins with 's', the pause is simulated; the time
     displayed is increased by INTERVAL but without performing any
     pause. Pause simulation can be useful in combination with
     '--test-mode' for testing purposes.


> 3. How the -K option works? Either it often misunderstood my input
> such as -K102400s or -K2000000s and set skip size not as I expected -
> or I have forgotten that used -b4096 instead of default -b512 ?? What
> is the right syntax for it, which units does it accept?

'-K [initial][,max]'

Maybe the problem is that you are setting only the initial skip size, 
which ddrescue doubles after each read error. If you want ddrescue to 
skip an exact amount after each read error, give the same value for 
initial and max:

  ddrescue -K102400s,102400s


Best regards,
Antonio.