Check that the dump device is large enough. Otherwise we could end up with a dump offset that's smaller than the start of the dump device and either clobber data in preceding partitions or try to write beyond the end of the medium (unsigned wrap).
Check that the dump device is large enough. Otherwise we could
end up with a dump offset that's smaller than the start of the
dump device and either clobber data in preceding partitions or
try to write beyond the end of the medium (unsigned wrap).

Implement legacy behaviour to never write to the first 64KB as
that is where metadata (ie disklabels) may reside.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase