Filesystem creation with integrated bad-block detection

[Pásztor Richárd]

I wonder if it would be possible to implement under freeebsd an interesting 
feature
which can be found in linux:

mkfs.ext2(8)
.......
-c
Check the device for bad blocks before creating the file system. If this 
option is specified twice, then a slower, destructive, read-write test is 
used instead of a fast read-only test.
...

I searched the archive for this subject, and i found that simple answer 
that modern hard drives have
the so called spare sectors, and if they cant do these reallocations 
transparently because they
ran out of those reserved sectors -> throw the drive into the trash.
But what abou using freebsd on older machines with hard drives that dont 
support spare sectors?
Having a few bad sectors doesnt mean that a 4-5 Gb driver is useless 
because one isnt able to mark those
few sectors.

ricsip