Andy Burns spake thus:

Rednadnerb wrote:

Isn't the bad sector mapping on the disk itself? I know it used to be.

Now it is. But way-back-when drives used to come with a printed defect
list you were expected to enter into your O/S,

Not quite correct. You entered the defect list when running a low-level
format, typically by executing code on the drive controller. The relevant
sectors were then marked as unusable on the drive, and would survive high-
level formats.

or you could leave the
O/S running a "comprehensive surface analysis" for a few days before
before making use of the drive.

Some OSes insisted on this.