| SWWDOG(4) | Device Drivers Manual | SWWDOG(4) | 
swwdog —
pseudo-device swwdog
swwdog driver provides a software watchdog timer
  that works with wdogctl(8). If
  the timer expires, the system reboots if the boolean variable
  swwdog_reboot is true;
  otherwise, the system will panic. swwdog_reboot is
  accessible as the sysctl(8)
  variable hw.swwdog.reboot and defaults to false.
The default period of swwdog is 60
    seconds.
As with other watchdog timers, the swwdog
    driver prevents a system from suspending when the watchdog is armed.
swwdog driver was written by Steven
  M. Bellovin.
swwdog device can be created.
Kernel tickle mode is useless with swwdog
    and arguably should be rejected, since both it and this driver rely on the
    same callout mechanism; if one is blocked, almost certainly the other is as
    well.
The alarm option to wdogctl(8) isn't implemented.
| June 8, 2011 | NetBSD 9.4 |