example% iostat -xtc 4

     disk      name of the disk

     r/s       reads per second

     w/s       writes per second

     Kr/s      kilobytes read per second

     Kw/s      kilobytes written per second

     wait      average number of transactions waiting for service
               (queue length)

     actv      average number of transactions actively being ser-
               viced  (removed  from  the  queue but not yet com-
               pleted)

     svc_t     average service time, in milliseconds

     %w        percent of time there are transactions waiting for
               service (queue non-empty)

     %b        percent of time the disk is busy (transactions  in
               progress)