You or the system administrator can view the current settings using the systune command (see the systune(1M) reference page). The system administrator can use systune to request changes in parameters. Some changes take effect at once; others are recorded in a modified kernel that is loaded the next time the system boots.
To retrieve certain tuning parameters from within a kernel-level device driver, include the header file sys/var.h.
The use of systune and its related files is covered in IRIX Administration: System Configuration and Operation.