[Coco] Challenge: identifying file type by sector of data

[Robert Gault]

Allen Huffman wrote:
> For my RS-DOS disk recovery tool (which I am writing mostly to recover a few BASIC programs I wrote), I can scan the directory and identify sectors that belong to files, and then have a list of all sectors not accounted for. In my case, I have a bad sector(s) in the middle of the directory so I lost references to however many files that is. (32 bytes per entry? 8 files?).
>
> To help the user, a sector with almost no high bit data (characters <128) could be flagged as potentially text, and they could be shown and the user could put them together.
>
> I wonder: would it also be possible to flag a sector of data and identify it as part of a tokenized BASIC program? I expect scanning the bytes looking for a series that could be a line number, following the offset to see if it's another series, would do it.
>
> Also, for assembly -- might there be tell-tale signs that it's 6809 code? A disassembler basically does this.
>
> Anyone ever done any data identification stuff for RS-DOS?
>
> 		-- Allen
>
>

What is wrong with the "bad" directory sector? It won't read? It can be read but 
is trashed? Can you make an image of one of these bad disks such that the "bad" 
sector content is the same as the real disk?
If you can make an image that is identical to the "bad" disk, send it to me.

Robert