The realtime directive specifies whether or not Heartbeat should try and take advantage of the operating system's realtime scheduling features. When enabled, Heartbeat will lock itself into memory, and raise its priority to a realtime priority (as set by the rtprio directive). This feature is mainly used for debugging various kinds of loops which might otherwise cripple the system and impair debugging them. The realtime flag is a HeartbeatBoolean value, whose default value is true. A sample realtime directive is shown below.