Short answer: no
Long answer: Not necessarily.
HPFS I know in particular uses B-trees that are very simple to read,
and much harder to update. I don't know of the other challenges,
although I assume they exist.
In general, being able to parse a data structure doesn't imply
knowledge of the invariants used while creating it. As an example
from a different domain, as I'm working on my scanner driver, I have
not yet been able (even with documentation) to get it to scan correctly.
However, if I had a SCSI sniffer between my box and the scanner, I would
be able to understand everything going on between the two.
Understanding what is going on parallels readonly, being able
to scan parallels read-write.
Does that help?
> Oh well. Just a personal pet peeve.
Short answer: So fix it...
Long answer: Do you really think that the people writing the
filesystems would stop at read-only if it were actually only
a little bit more work to add read-write, or if they had the
info right there, or if they trusted their knowledge of the
data structures enough? The filesystem authors I know really
aren't trying to annoy people...
michaelkjohnson