Re: [Bug-ddrescue] Why doesn't ddrescue revert to full speed long after a bad read?

[Scott D]

I have done some testing, and found that I was WRONG! This behavior does 
NOT seem to happen when direct disc mode is used. But I can consistently 
get it to happen in normal mode. I am willing to do further testing if 
asked, as I can reproduce the result very quickly and consistently right 
now on a drive. Also note that for this test I am using a USB to SATA 
bridge, but I almost positive that I have seen this when reading an 
internal disk (note that I said "almost positive").

For now I think I am just going to make -d a normal option for me, as it 
always seems to read faster especially through error sections.

On 3/26/2013 5:54 PM, Scott Dwyer wrote:
> I too have observed this same behavior of the read of good sectors 
> being slow after encountering errors, and stopping and restarting 
> resumes at a good read speed again. I will make a note to check for 
> sure in the future, but I am pretty sure it happens with direct disc 
> mode also.
>
>
> On 3/26/2013 12:07 PM, Antonio Diaz Diaz wrote:
> > Paul L Daniels wrote:
> > > Not sure if I'm missing something, but I've noticed that after a bad
> > > read ddrescue never returns back to the full speed capability, however,
> > > if I cancel the process and restart it (obviously with a log) it
> > > immediately returns to full speed.
> >
> > I do not remember to have observed this behaviour, but my drives are 
> > far slower than the ones you seem to be using. If you are missing 
> > something, then I am also missing it. :-)
> >
> >
> > > This behaviour has been seen on multiple versions of ddrescue and
> > > multiple different drives and systems. Am I missing something obvious?
> >
> > Maybe it is some internal switch of caching modes. Does this also 
> > happen with direct disc mode (option -d)?
> >
> >
> > Regards,
> > Antonio.
> >
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