Bad sectors: how bad can it be

[Grünewald Michaël]

Dear list,

after an incorrect power-off of my FreeBSD system, it does not boot  
any more, BTX stops even before showing the cute beastie menu.  
Starting the machine by other means, I found that the hard-drive is  
installed on has bad sectors. I am looking for advices on how to  
recover from this, if possible.

Basically the question is: shall I discard my hard-drive with bad- 
sectors, or can I continue using it?

The Linux system I use to diagnose this says:

   hdb: media error (bad sector): status=0x51 { DriveReady  
SeekComplete Error }
   hdb: media error (bad sector): error=0x30 { LastFailedSense=0x03 }
   ...
   Buffer I/O error on device hdb, logical block 1663200

etc.

Since I use computers (1992) these are my first bad sectors :) (on  
hard drives, taking floppies into account is no fun!). I hence have  
several questions:
   -- is it possible to let these sectors?
   -- to which extents a hard-drive with bad sectors is usable?
   -- while the apparition of these bad sectors coincide with an  
incorrect power-off, are the two events related? The machine suffered  
plenty improper power-offs (or many), in the last years and did not  
react so badly!
-- 
Thank you in advance for your advices,
Michaël