Watchdog is intended for use on servers working in the round-the-clock unattended mode. It restores an operation of the server by the hardware reset of a computer in case of the operating system hang-up.
The watchdog is fitted into a standard DB-25 connector, with two additional cables. It must be connected to the LPT port of a computer, additional cables are connected to RESET contacts on the motherboard, and to the keyboard connector.
After computer powerup or cold reset, the watchdog is in a passive state and
does not affect the operation of a computer. After the operating system startup,
the watchdog driver will initialize it and set up the timeout value:
100 msec, 1 sec, 5 sec, 10 sec, 20 sec, 40 sec or 60 sec.
During the normal system operation the watchdog software periodically
signals the watchdog that the computer is alive.
In a case of operating system hang up, after the timeout elapsed,
the watchdog will perform a cold reset of the computer.