Re: data-preserving HDD diagnostic program?

I originally asked:

Is there a good FreeBSD HDD diagnostic program?

The SATA III disk drive I'd like to test is either partially failing
or has corrupted data.  MS Win10's "repair" of the drive isn't fixing
it. For that and other reasons, I suspect the drive has partially died
(such as maybe 1 head died or something).

to which Marco Moock <mm+usenet-es@dorfdsl.de> kindly replied:

badblocks can use a read-only mode and also a non-destructive write mode.

"badblocks"?  'pkg rquery %n badblocks' finds no such program.
 -WBE