Implement a write test

[baruch]

A write test needs to be implemented for the rare occasion when writes fail.

possibly do a read after the write to verify the write.

[baruch]

Would be useful to include full media verification in the sense that we generate a unique 512 block for each sector and then when reading verify that it is all the same so there is no data corruption. This can be useful to check for fake SD cards or completely unstable media.

[Stoatwblr]

Suggestion:

If you're going to write-test to deal with sector problems then it would make sense to call hdparm's --repair-sector option and make that a prerequisite for diskscan