Re: [Bug-ddrescue] Appending zeroes by seek is not working

[Florian Sedivy]

Am 13.12.2014 um 06:28 schrieb Pavel Roskin:

> Here's a related but different issue.
> 
> rm foo
> ddrescue -o 2048 -s 1 /dev/null foo
> ls -l foo
> 
> The resulting file "foo" is 0 bytes long. Apparently, the seek is never
> performed because /dev/null is empty. I believe the seek should be
> performed if it's explicitly requested on the command line.

For what its worth, using the --extend-outfile option (and a non-empty rescue 
domain) it works even with ddrescue: 
rm foo
ddrescue -x 2048 -s 1 /dev/null foo
ls -l foo
-> foo is exactly 2048 bytes

While --preallocate on the other hand seems to never get triggered as long as 
/dev/null is the input file. 
rm foo
ddrescue -o 2048 -s 1024 -p /dev/null foo
ls -l foo
-> ddrescue gives the warning: "Preallocation not available", foo is created, 
but remains 0 byte. 

My testing done with ddrescue 1.19 on OS X 10.7.5

Greetings, 
Florian