I have used
shred on my HDD, but in the middle of that, I used Ctrl+C combination accidentally. After that I noticed bad sectors on Disk Assessment. I am using Linux mint 18 as my OS.
fsck, I tried to fix the broken sectors. I have rebooted the system , again I can see bad sectors on Disk Assessment
After I while I formatted my HD with zeros. After that the broken sectors got increased. I ran
SMART, both short and long DST got passed. Still I can see bad sectors on Disk Assessment.