China DOS Union

When a hard drive has bad sectors, can low-level formatting erase the bad sectors?
If that's the case,
then when I'm buying a hard drive, how can I tell whether it's a new drive or
a drive that someone repaired with low-level formatting?

Physical bad sectors are only masked out; they can't really be repaired, although some software now claims it can do that...

If there are physical bad sectors, then a fairly large area adjacent to the physical bad sectors also has to be masked out. Only then is it possible for the heads not to read the part with the physical bad sectors. In that case, the drive's capacity will be a bit smaller than its original capacity.

Software can't cause physical damage, and of course it also can't repair hard (physical) bad sectors.

For a new hard drive, you can look at the manufacturing date (XX year XX week).
If it was sent back to the hard drive manufacturer for repair, the manufacturer will mark it on the drive, seems like an R mark inside a circle or something. I don't quite remember. Hehe...
If it was repaired by someone in a computer shop using "Lformat", then it's harder to tell. This kind of drive generally hasn't yet reached the point of physical damage, but it still won't last long...

Hard... I don't know.

Too specialized. Generally speaking, tool-based test results can only be used for reference. I tried it before: after low-level formatting, NDD no longer reported errors, but the hard drive still failed again very soon.

Use the Xiaolvyuan hard drive testing tool