Re: [Bug-ddrescue] Forgot the mapfile.....

[Robert Backhaus]

If the disk you are writing too was blank before you started - i.e. it was
either new or had been filled with zeros - you can use -G (--generate-mode)
to create an approximate mapfile.

ddrescue --generate-mode infile outfile mapfile

It will read the entire outfile and generate a mapfile that assumes that
anything with data is recovered data, and anything with zeros is
unrecovered.

If the destination disk had data on it, however, you can't be sure what is
old data and what is good, recovered data

On Fri, 15 Feb 2019 at 07:32, David Morrison <address@hidden>
wrote:

> I have a disk recovery under way. I used this command on a Mac:
>
> sudo ddrescue -f -r3 /dev/disk2 /dev/disk1
>
> However, I forgot to put a mapfile name. So, a few questions:
>
> 1. Where is the mapfile being written? Can I recover it?
>
> 2. Since mapfile is an essential argument to the command, could it be
> writing the mapfile on /dev/disk1?  Aarrgghh!!!
>
> If the latter (and I hope not), could I suggest some more rigorous
> checking of arguments might be desirable. As it is, I have
> potentially wasted 15 hours of copying of a disk with lots of read
> errors. :-(
>
> 3. If I need to interrupt a ddrescue run, is it ok to CTRL/C it, then
> start running it again later, assuming there is actually a mapfile
> somewhere? (I have tradesmen coming today who may need to turn the
> power off.)
>
> Thanks
>
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