Re: [Bug-ddrescue] direct disk access will not read partial sector

[Antonio Diaz Diaz]

Hello Scott,

Scott Dwyer wrote:
> I do not know if this would be considered a bug, or just the nature of 
> the direct disk access. When using the -d option, ddrescue will not 
> attempt to read data that does not start or end on a sector boundary. 

I thinh it is the nature of direct disk access. The kernel does not 
accept such partial sector reads.

Of course partial reads could be faked by reading the whole sector and 
writing only the requested part. AFAIK neither linux nor glibc implement 
this with direct disk access. I am not sure if it would be a good idea 
for ddrescue to implement it or not. It may mean reading the same sector 
more than once in extreme cases of domain fragmentation. But I guess 
such domains are even less normal that what you are doing. :-)


Regards,
Antonio.