Salvaging and scrubbing hard drives from a couple of retired machines, one threw hard disk drive errors repeatedly and ended up in the “Repair” pile. Got to it this week, following the instructions at linoxide.com (search for ‘bad blocks’) and was successfully able to mark the bad block and force the drive to work around it. New large-capacity drives have “spare” sectors allocated for this purpose and all drives will have a few flaws, so this drive can be put back into production, as long as it is monitored and any future problems dealt with quickly. As always, all hardware will fail, and a thoughtful backup strategy (on another spindle, on another machine, in another location, in a different time zone, on a different planet) is important.