The history of computer science began long before the modern discipline ofcomputer science that emerged in the 20th century, and hinted at in the centuries prior.[dubious – discuss][citation needed] The progression, from mechanical inventions and mathematical theories towards the modern computer concepts and machines, formed a major academic field and the basis of a massive worldwide industry.[1]
The earliest known tool for use in computation was the abacus, developed in period 2700–2300 BCE in Sumer .[citation needed] The Sumerians’ abacus consisted of a table of successive columns which delimited the successive orders of magnitude of their sexagesimal number system.[2] Its original style of usage was by lines drawn in sand with pebbles .[citation needed]Abaci of a more modern design are still used as calculation tools today.[3]

The Antikythera mechanism is believed to be the earliest known mechanical analog computer.[4] It was designed to calculate astronomical positions. It was discovered in 1901 in theAntikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to c. 100 BCE. Technological artifacts of similar complexity did not reappear until the 14th century, when mechanical astronomical clocks appeared in Europe.[5]

When John Napier discovered logarithms for computational purposes in the early 17th century,[citation needed] there followed a period of considerable progress by inventors and scientists in making calculating tools. In 1623Wilhelm Schickard designed a calculating machine, but abandoned the project, when the prototype he had started building was destroyed by a fire in 1624 .[citation needed] Around 1640, Blaise Pascal, a leading French mathematician, constructed a mechanical adding device based on a design described byGreekmathematician Hero of Alexandria.[6] Then in 1672 Gottfried Wilhelm Leibnitzinvented the Stepped Reckoner which he completed in 1694.[7]