Hi,
If the keys are out of order, or index nodes are pointing to the wrong nodes, you are more likely to get some kind of "not found" error. The "Read/Write error" and "Wrong logical location" suggest that some number (such as a node number in an index node) is out of range. Another possibility is that the extent information or end-of-file for the B-tree is wrong (probably too few allocation blocks), so the node numbers refer to offsets beyond what the File Manager things is the end of the B-tree.
I finally found out what the error was due to. Thanks for the explanation regarding the sequence of events - I didn't know that Mac iterates thru' the leaf nodes at the start. The problem was with the index nodes present in the final sectors which had got currupted while recording onto a disk. Since the Mac didn't complain about the absence of an alternate MDB and I used a local image for verification I didn't quite understand what was happening.... now that the final sectors have been 'set right' the index nodes are also read correctly and all the files can be opened.
I've been following up threads on other lists as well. I would just like to convey to the list that I think that Apple is doing a great job out here. Everyone has rules which have to be stuck to though rules can never be in the interests of everybody and may not be always fair in everyone's eyes. I just want to mention that the Apple employees don't have to reply to every email they get but the fact that some of them do find the time to do so has to be appreciated. I'd probably be totally lost but for the tips I get from them once in a while. Thanks !
Regards, Nandini Hengen