Re: allocation bitmaps

[Antonio Diaz Diaz]

Hi Florian,

Florian Sedivy wrote:
> I propose to concentrate on the raw format, just as those allocation
> bitmaps are stored on the drive by the respective filesystem
> specifications. That makes ddrescuelog independent of the possibly
> proprietary formats some tools would use to store backups of them. More
> importantly it allows reading or writing those bitmap files with direct
> disk access tools - like ddrescue.

Even concentrating on the raw format seems to need a lot of research work. 
For example, given an image of a partition with a file system of type ext3, 
what is the command required to read the block bitmap(s) from the image 
using ddrescue? What is the mapping between file system blocks and drive 
sectors?

As time permits, I'll try to investigate this for ext2/3/4 file systems. 
Concrete data (command used and format of resulting bitmap file) for these 
or other types are welcome.

Best regards,
Antonio.