The earliest device that qualifies as a digital computer is?
The earliest device that qualifies as a digital computer is Abacus
The history of computing hardware covers the developments from early simple devices to aid calculation to modern day computers. Before the 20th century, most calculations were done by humans. Early mechanical tools to help humans with digital calculations, such as the abacus, were called "calculating machines", called by proprietary names, or referred to as calculators. The machine operator was called the computer.