Re: [Bug-ddrescue] Request for an Especific Clone Direction Option

[Scott Dwyer]

On 5/19/2014 11:42 AM, Antonio Diaz Diaz wrote:
> Even if all passes are made in the same direction, ddrescue will go 
> twice per pass over any area (unwanted or not) that is between rescue 
> domain extremes, because it must go back to the beginning to start the 
> next pass.
>
> There is a way to make ddrescue perform the copy phase in just one 
> pass, and therefore in one direction; disable skipping with 
> '--skip-size=0'.

I for one am happy to see the ability to to turn off skipping in this 
latest release. While ddrescue has what could be considered the best 
"logical" algorithm for data recovery, sometimes it is not the best 
"physical" thing for a disk. I think we would like to see and understand 
whatever options would be needed to get ddrescue to go in a "strait 
line" and "do what I say" when desired. I have not had much time lately, 
but I was not too long ago doing some benchmarking with different 
versions and options, and can say that I have seen some very nasty plots 
of the head bouncing all over the place. I know one thing that helps is 
to increase the logfile-size option. If I can ever find the time again, 
I will do more testing. But I do agree that some of us would like more 
control, and are sometimes unsure of how to properly use the options to 
get it.

Antonio, I did just finally do a quick benchmark of 1.18-rc1 and do not 
have any anomalies to report.

Scott