You might want to try the Drive Fitness Test from IBM:
http://www.storage.ibm.com/hdd/support/download.htm#DFT

It is a dd image of a bootable PC-DOS floppy.

If the laptop drive is an IBM device it can map and flag the bad blocks in
the drive firmware tables. Non IBM drives can also be tested but I'm not
sure if the blocks can be flagged in firmware.

--et

> Greetings:
>
> I have a 20GB laptop drive that is currently formated with Win32.
> Unfortunately, this drive has a couple of bad blocks in the middle of
> the disk, and these bad blocks are marked "BAD" in Win32.  Other than
> the bad blocks, the disk runs fine, since Win32 avoids using
> these marked bad blocks.
>
> I wish to reformat this disk with NetBSD's netive filesystem.
> However, I was wondering if it was possible to have newfs avoid
> using these bad blocks.  Can newfs do a disk surface scan or other- wise
> try to identify the bad disk blocks that were previously
> identified in Win32?  I hope to have the NetBSD filesystem also
> avoid the bad disk blocks in the same way that Win32 does.
>
> Thank you in advance.
> Alicia.
>