Questions Linux Datarecovery! Testdisk, Photorec, Inodes etc


I am using currently photorec, testdisk etc. for recovering files on a lost partition. My questions:

  1. the files dumped by photorec have filenames like fnnnnnnn_pidxxx.txt. Is now the number after the “f” the on-disk block number on on-disk-byteposition, cluster number etc?
  2. If I extract by substr func this number - in case of on-disk block number - I can access directly the data by hexeditor or hexdump etc. isn’t it?
  3. Is there any possibility to get back by these numbers to the directory inode or other inode structs?
  4. Can I use a linux strings | grep -i “filename” or grep -i “some id string” to get e.g. a byte pos/block pos of file and then get back to the inodes
  5. In e.g. Amiga filesystem (that Commoder 1980’s home computer) there was a 4 byte ID “DIR\0” etc. for eacht on disk structures. That made recovery much more easier. Why does not Linux (the ext2 filesystem developers) do that?

Thanks for serious answers