I don't totally understand what you are trying to do... Using Bffs to
write something on it?

But it looks, like the disks are formatted in 880 kByte format, and you're
trying to access them with 720kB format.

(Replace with 1760k/1440k if applicable).

The 512-Byte-block nr. 16 is the first one used by the Berkeley
filesystem (its the beginning of the "superblock"); it is the first
one which must be accessed to get to the files on the filesystem.

	-is

Regards,