This is not a dissertation. The old SPINRITE used transfer speed among other tests to call a track or sector bad. But here's the thing. Drives since about 2000 implement spare tracks and sectors and when you see bad sectors reported the drive is now in failure mode. No one I know will keep such a drive. It's gone.
I was searching for bad sector in hard drive. so, i ran a software , Hd_speed, on hard drive it gave a log file. that log file gives speed in kb/s of sectors. i see 0kb/s in some sectors. Also few hundreds kb/s and mostly in thousands kb/s. Low speed means bad sector but i want to know, below what speed should i consider the sector as bad sector?

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