The history of computer science began long before the modern discipline of computer science that emerged in the twentieth century, and hinted at in the centuries prior. The progression, from mechanical inventions and mathematical theories towards the modern concepts and machines, formed a major academic field and the basis of a massive worldwide industry.
The earliest known tool for use in computation was the abacus, and it was thought to have been invented in Babylon circa 2400 BCE. Its original style of usage was by lines drawn in sand with pebbles. This was the first known computer and most advanced system of calculation known to date - preceding Greek methods by 2,000 years. Abaci of a more modern design are still used as calculation tools today.
In 1115 BCE, the South Pointing Chariot was invented in ancient China. It was the first known geared mechanism to use a differential gear, which was later used in analog computers. The Chinese also invented a more sophisticated abacus from around the 2nd century BCE, known as the Chinese abacus.
In the 5th century BCE in ancient India, the grammarian Pāṇini formulated the grammar of Sanskrit in 3959 rules known as the Ashtadhyayi which was highly systematized and technical. Panini used metarules, transformations and recursions.
The Antikythera mechanism is believed to be the earliest known mechanical analog computer.[2] It was designed to calculate astronomical positions. It was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa 100 BC. Technological artifacts of similar complexity did not reappear until the 14th century, when mechanical astronomical clocks appeared in Europe.[3]
Mechanical analog computing devices appeared again a thousand years later in the medieval Islamic world. Examples of devices from this period include the equatorium by Arzachel,[4] the mechanical geared astrolabe by Abū Rayhān al-Bīrūnī,[5] and the torquetum by Jabir ibn Aflah.[6] Muslim engineers built a number of Automata, including some musical automata that could be 'programmed' to play different musical patterns. These devices were developed by the Banū Mūsā brothers[7] and Al-Jazari[8] Muslim mathematicians also made important advances in cryptography, such as the development of cryptanalysis and frequency analysis by Alkindus.[9]
When John Napier discovered logarithms for computational purposes in the early 17th century, there followed a period of considerable progress by inventors and scientists in making calculating tools. In 1623 Wilhelm Schickard designed a calculating machine, but abandoned the project, when the prototype he had started building was destroyed by a fire in 1624. Around 1640, Blaise Pascal, a leading French mathematician, constructed the first mechanical adding device[10] based on a design described by Greek mathematician Hero of Alexandria.[11] Then in 1672 Gottfried Wilhelm Leibniz invented the Stepped Reckoner which he completed in 1694.[12]
None of the early computational devices were really computers in the modern sense, and it took considerable advancement in mathematics and theory before the first modern computers could be designed.
