Re: [Bug-ddrescue] Slow reads for x time to exit and whitespace skipping

[Scott Dwyer]

I am going to step in and give my opinion on this. Trying to figure out 
how to skip possible unused data blocks is like playing roulette. There 
is no way to tell until you either win or loose. Only by processing the 
raw file system can this even be possible. I am doing some very creative 
things with my own cloning tool, but this idea is just madness. There is 
no way to tell what is used and not used without processing the file 
system. Please don't ask Antonio to attempt something that can't 
possibly work with any sort of consistency. It would be a waste of time 
and effort.

Regards,
Scott


On 1/25/2017 10:50 PM, Paul Daniels wrote:
> On 26/01/17 08:20, Rog Fanther wrote:
> > My 2 cents :
> >
> > What would constitute an "empty" part ? Sometimes, blocks filled with 
> > 00 or FF or any value may be legitimate parts of a file.
> > To know which blocks are really used for files, ddrescue would have 
> > to analyse the filesystem allocation and, at least to me, that seems 
> > to disrupt the idea of cloning the disk.
>
> You could specify.  Usually you can see it quickly enough when you're 
> recovering the drive; so you could provide a sample block or 
> byte-sequence for ddrescue to match against, and ddrescue defaulting 
> to just a full block of 0x00.
>
>
>
> > ----- Original Message ----- From: "Antonio Diaz Diaz" <address@hidden>
> > To: "Cameron Andrews" <address@hidden>
> > Cc: <address@hidden>
> > Sent: Wednesday, January 25, 2017 11:11 AM
> > Subject: Re: [Bug-ddrescue] Slow reads for x time to exit and 
> > whitespace skipping
> >
> >
> > > Hi Cameron,
> > >
> > > >
> > > Skipping the empty parts of the drive will have to wait until 1.23. 
> > > I also will need more feedback about how should ddrescue decide if a 
> > > block is empty.
> > >
> > > Thank you very much for your donation.
> > >
> > >
> > > Best regards,
> > > Antonio.
> > >
> > >
> > > _______________________________________________
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> > > https://lists.gnu.org/mailman/listinfo/bug-ddrescue 
> >
> >
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