IOSTAT(8)                                               IOSTAT(8)


NAME
       iostat - report I/O statistics

SYNOPSIS
       iostat [-c count] [-w wait] [-M core] [-N system] [drives]

DESCRIPTION
       Iostat reports certain kernel statistics kept about termi-
       nal, disk and cpu activity.

       The options are as follows:

       -c     Repeat the display count times.  The first  display
              is  for the time since a reboot and each subsequent
              report is for the time period since the  last  dis-
              play.   If  no  wait  interval  is  specified,  the
              default is 1 second.

       -w     Pause wait seconds between  each  display.   If  no
              repeat count is specified, the default is infinity.

       -M     Extract values associated with the name  list  from
              the   specified   core   instead   of  the  default
              ``/dev/kmem''.

       -N     Extract the name list  from  the  specified  system
              instead of the default ``/bsd''.

       Iostat displays its information in the following format:

       tty
              tin  characters read from terminals
              tout characters written to terminals

       disks  Disk  operations  (this field is system dependent).
              The header of the field is the disk name  and  unit
              number.   If more than four disk drives are config-
              ured in the system, iostat displays only the  first
              four  drives.   To force iostat to display specific
              drives, their names may be supplied on the  command
              line.

              sps  sectors transferred per second
              tps  transfers per second
              msps milliseconds per average seek (including implied
                   seeks and rotational latency)

       cpu
              us   % of cpu time in user mode
              ni   % of cpu time in user mode running niced processes
              sy   % of cpu time in system mode
              id   % of cpu time in idle mode





                          April 24, 1991                        1

IOSTAT(8)                                               IOSTAT(8)


FILES
       /bsd       default kernel namelist
       /dev/kmem  default memory file

SEE ALSO
       fstat(1),   netstat(1),   nfsstat(1),   ps(1),  systat(1),
       vmstat(1), pstat(8)

       The sections starting with  ``Interpreting  system  activ-
       ity'' in Installing and Operating 4.3BSD.















































                          April 24, 1991                        2