Back in the days when there were bad proprietary IDE controller chipsets that enumerated differently under Linux than they did windows...<p>Well, as a kid I clobbered my windows install while trying to destructively check the validity of a disk.  Checks to see if a filesystem is mounted won&#x27;t protect you if it isn&#x27;t.<p>Since then I&#x27;ve been -extremely- careful for any destructive operation on block devices, and generally careful otherwise.<p>Also, I don&#x27;t know if blkid existed at the time, but it&#x27;s &#x2F;very&#x2F; useful in avoiding those types of mistakes.