IOSTAT(1) UNIX Programmer's Manual IOSTAT(1) NAME iostat - report I/O statistics SYNOPSIS iostat [ interval [ count ] ] DESCRIPTION _I_o_s_t_a_t iteratively reports the number of characters read and written to terminals, and, for each disk, the number of seeks and transfers per second, and the milliseconds per average seek. It also gives the percentage of time the sys- tem has spent in user mode, in user mode running low prior- ity (niced) processes, in system mode, and idling. To compute this information, for each disk, seeks and data transfer completions and number of words transferred are counted; for terminals collectively, the number of input and output characters are counted. Also, each sixtieth of a second, the state of each disk is examined and a tally is made if the disk is active. From these numbers and given the transfer rates of the devices it is possible to deter- mine average seek times for each device. The optional _i_n_t_e_r_v_a_l argument causes _i_o_s_t_a_t to report once each _i_n_t_e_r_v_a_l seconds. The first report is for all time since a reboot and each subsequent report is for the last interval only. The optional _c_o_u_n_t argument restricts the number of reports. FILES /dev/kmem /vmunix SEE ALSO vmstat(1) Printed 11/10/80 1