Strange messages from fsck_hfs

I am trying to check an entire USB external disk that is not erased. For that reason I have typed fsck_hfs -fy -l -S -d /dev/disk1s2 This the result Several messages I found strange here 1. NO WRITE - how can that be? If I am trying to fix it how can it be no write? 2. ok, it found a bad block at 137228189184 but at end it says the disk is OK 3. what is block 26023808 NO MATCH? 4. at end it says fsmodified = 0??? No modification performed? I don't understand this. Have fsck_hfs fixed my disk? I by fixed I mean mark the block as unusable or reformatted it or whatever? Thanks