A mule is the offspring of a male donkey (jack) and a female horse (mare). Horses and donkeys are different species, with different numbers of chromosomes. Of the two F1 hybrids between these two species, a mule is easier to obtain than a hinny, which is the offspring of a female donkey (jenny) and a male horse (stallion). The size of a mule and work to which it is put depend largely on the breeding of the mule's female parent (dam). Mules can be lightweight, medium weight, or when produced from draft horse mares, of moderately heavy weight. Mules are more patient, hardy and long-lived than horses...

Not to be confused with Computer speaker. A PC speaker is a loudspeaker built into most IBM PC compatible computers. The first IBM Personal Computer, model 5150, employed a standard 2.25 inch magnetic driven speaker. More recent computers use a piezoelectric speaker instead. The speaker allows software and firmware to provide auditory feedback to a user, such as to report a hardware fault. A PC speaker generates waveforms using the programmable interval timer. == Usage == === BIOS error codes === The PC speaker is generally the first output device to be activated during the boot process. Since it...

Ontology is the philosophical study of the nature of being, becoming, existence or reality as well as the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology often deals with questions concerning what entities exist or may be said to exist and how such entities may be grouped, related within a hierarchy, and subdivided according to similarities and differences. Although ontology as a philosophical enterprise is highly theoretical, it also has practical application in information science and technology, such...