Wdt

Wdt is an acronym that most commonly refers to the watchdog timer, a device or software component used to detect and recover from malfunctions in digital systems. A watchdog timer monitors the software’s progress and can trigger a system reset or other corrective action if the program becomes unresponsive.

Operation and purpose: A watchdog timer starts a countdown from a preset value. The running software must periodically reset or “feed” the timer before it expires. If the timer reaches zero, it typically causes a reset of the processor or raises an interrupt to initiate recovery procedures. Hardware watchdogs are often integrated into microcontrollers or system-on-chips, while software watchdogs run in higher-level environments. Timers may offer different modes, such as a simple timeout, interrupt plus reset, or windowed operation that requires feeding within a specific time window to avoid accidental expiry.

Implementation and usage: WDTs are widely used in embedded systems, networking equipment, consumer electronics, industrial controllers, and automotive electronics to increase system reliability and fault tolerance. They can be configured with various timeout periods and actions, and may include features such as a pre-reset warning, persistent state preservation, or the option to disable resets during maintenance windows in a controlled manner.

In Linux and other operating systems, watchdog functionality is provided by a kernel subsystem that exposes devices such as /dev/watchdog*. User-space programs or daemons feed the watchdog to indicate healthy operation, or allow automated recovery if the feed stops.

Other uses: While Wdt most commonly denotes the watchdog timer, the acronym can have other meanings in different fields. This article focuses on the watchdog timer interpretation.