Thus the software environment itself can be made relatively
unspoofable.
If this is the case, then the same environment can protect the database.
Why can't the OS maintain hashes of the database as well?
I guess it is possible to have only the executables on read only media
as you suggested but this in and of itself is not sufficient. You
must insure that only that version of the executable is run and it
is not the case that someone placed a link to a bogus copy or something.
I guess I just don't happen to know of any such environment.
The NFS example of Derek's says very little for in that environment,
the same attach against the database can be used against the executable.
-Ray