if you run blid on a bad disk it first issues a request
for 32 sectors to sector 0, then 31 to sector 1, then
30 to sector 2, etc. After that, it tries to read
sector 32, following the same pattern.
This means with a bad disk in your system you will have
several hundred i/o error messages each time blkid runs.
If blkid gets an error on a read, it should skip the
drive and move on to the next.