heartbeat

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heartbeat

[′härt‚bēt]
(physiology)
Pulsation of the heart coincident with ventricular systole.

heartbeat

(networking)
The signal emitted by a Level 2 Ethernet transceiver at the end of every packet to show that the collision-detection circuit is still connected.

heartbeat

(2)
A periodic synchronisation signal used by software or hardware, such as a bus clock or a periodic interrupt.

heartbeat

(3)
The "natural" oscillation frequency of a computer's clock crystal, before frequency division down to the machine's clock rate.

heartbeat

(4)
A signal emitted at regular intervals by software to demonstrate that it is still alive. Sometimes hardware is designed to reboot the machine if it stops hearing a heartbeat. See also breath-of-life packet, watchdog.

heartbeat

(1) A periodic signal generated by hardware for activation and/or synchronization purposes. See MHz.

(2) A periodic signal generated by hardware or software to indicate that it is still running.
References in classic literature ?
Though no one had told him not to go in, he had a feeling that it would be wrong to do so; he was a little frightened, and his heart beat uncomfortably; but at the same time something impelled him to turn the handle.
My heart beat fast, my voice faltered--but I summoned courage enough to take his hand, and to make a last appeal to him.
Her heart beat fast, and as she spoke she flew from the house like a maniac, with her waiting-women following after.
Her lips were a little parted, as if her heart beat faster than usual.
Then, when he had assured himself that he could neither be seen nor heard, and was consequently relieved of doubts, he said, -- "Thanks, madame, -- thanks for your punctuality; "and he offered a chair to Madame Danglars, which she accepted, for her heart beat so violently that she felt nearly suffocated.
Only, I wonder--the thing one's so certain of in advance: can it ever make one's heart beat as wildly?
And this tattooing, had been the work of a departed prophet and seer of his island, who, by those hieroglyphic marks, had written out on his body a complete theory of the heavens and the earth, and a mystical treatise on the art of attaining truth; so that Queequeg in his own proper person was a riddle to unfold; a wondrous work in one volume; but whose mysteries not even himself could read, though his own live heart beat against them; and these mysteries were therefore destined in the end to moulder away with the living parchment whereon they were inscribed, and so be unsolved to the last.
Her head whirled and her heart beat until it hurt her.
His heart beat quickly when he bethought himself of this; and he half resolved to turn back.
On reaching this sanctuary of the florist he stopped, supporting himself against the table; his legs failed him, his heart beat as if it would choke him.
Dorothy knew at once it was a magic carpet she beheld, and her heart beat high with hope and joy as she realized she was soon to be rescued and allowed to greet her dearly beloved friends of Oz--the Scarecrow, the Tin Woodman and the Cowardly Lion.
Oh, how Gerda's heart beat with anxiety and longing