Heartbeat

Cardiac cycle

The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following a period of robust contraction and pumping of blood, called systole. After emptying, the heart relaxes and expands to receive another influx of blood returning from the lungs and other systems of the body, before again contracting.

Heartbeat (computing)

In computer science, a heartbeat is a periodic signal generated by hardware or software to indicate normal operation or to synchronize other parts of a computer system. Heartbeat mechanism is one of the common techniques in mission critical systems for providing high availability and fault tolerance of network services by detecting the network or systems failures of nodes or daemons which belongs to a network cluster—administered by a master server—for the purpose of automatic adaptation and rebalancing of the system by using the remaining redundant nodes on the cluster to take over the load of failed nodes for providing constant services. Usually a heartbeat is sent between machines at a regular interval in the order of seconds; a heartbeat message. If the endpoint does not receive a heartbeat for a time—usually a few heartbeat intervals—the machine that should have sent the heartbeat is assumed to have failed. Heartbeat messages are typically sent non-stop on a periodic or recurring basis from the originator's start-up until the originator's shutdown. When the destination identifies a lack of heartbeat messages during an anticipated arrival period, the destination may determine that the originator has failed, shutdown, or is generally no longer available.

Heartbeat (British TV series)

Heartbeat is a British police procedural period drama series, based upon the Constable series of novels written by Nicholas Rhea, and produced by Yorkshire Television until it was merged with ITV, then by ITV Studios, from 1992 until 2010. The series is set in the North Riding of Yorkshire during the 1960s, with plots centred on the fictional locations of Aidensfield and Ashfordly.

heartbeat

Noun

1. One pulsation of the heart; especially an irregular one, hence the emotion which causes it.
2. The rhythm at which a heart pulsates, a cardiac indicator.