Low level hard drive reading

[Gabriel]

Hello,
I have to write linux application that will analyze disk/partition (ext3 
filesystem) on really low level. It has to find/analyze files on the 
disk by reading disk blocks to analyze file's headers to find out file 
type and  then blocks related to file to  get file content. The second 
part have to be searching deleted files by this blocks reading (is this 
even possible?)

Can i do this in python? For example can i open disk image file and read 
it block by block?
Or is there even better solution? .) I tried search web but I wasn't 
successful..

I will appreciate any help. Thank you in advice..

Gabriel