On Mon, 7 Feb 2000 12:15:04 +0900 (JST) 
 Atsushi Onoe <onoe@sm.sony.co.jp> wrote:

 > Is it still meaningful?  I think we cannot use actual cylinder number since
 > zone bit recording makes the physical layout unknown to us.

Most disks are ZBR, but some are still old-style... we support lots of
older machines :-)

On these systems, you call disksort_cylinder().  On ZBR disks,
disksort_blkno().

 > Anyway, I just use b_cylinder to store raw blkno and call disksort_cylinder(),
 > and find my notebook extremely improves its performance.

Well, it's good to know that it had such a dramatic performance improvement
for you!

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>