history of computer

The history of computer science began long before the modern discipline of computer science that emerged in the 20th century, and was hinted at in the centuries prior.The progression, from mechanical inventions and mathematicaltheories towards modern computer concepts and machines, led to a major academic field and the basis of a massive worldwide industry.

The earliest known tool for use in computation was the abacus, developed in the period between 2700–2300 BCE inSumer.The Sumerians' abacus consisted of a table of successive columns which delimited the successive orders of magnitude of their sexagesimal number system.^:11 Its original style of usage was by lines drawn in sand with pebbles .Abaci of a more modern design are still used as calculation tools today.

The Antikythera mechanism is believed to be the earliest known mechanical analog computer.It was designed to calculate astronomical positions. It was discovered in 1901 in the Antikythera wreck off the Greekisland 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 inEurope.

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 1623Wilhelm 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 a mechanical adding device based on a design described byGreek mathematician Hero of Alexandria.Then in 1672 Gottfried Wilhelm Leibnizinvented the Stepped Reckoner which he completed in 1694.

In 1837 Charles Babbage first described hisAnalytical Engine which is accepted as the first design for a modern computer. The analytical engine had expandable memory, an arithmetic unit, and logic processing capabilities able to interpret a programming language with loops and conditional branching. Although never built, the design has been studied extensively and is understood to be Turing equivalent. The analytical engine would have had a memory capacity of less than 1 kilobyte of memory and a clock speed of less than 10 Hertz .

Considerable advancement in mathematics and electronics theory was required before the first modern computers could be designed.

Apple

Apple Inc. is an American multinationaltechnology company headquartered inCupertino, California, that designs, develops, and sells consumer electronics, computer software, and online services. Its hardwareproducts include the iPhone smartphone, theiPad tablet computer

, the Mac personal computer, the iPod portable media player, theApple Watch smartwatch, and the Apple TVdigital media player. Apple's consumer software includes the macOS and iOSoperating systems, the iTunes media player, the Safari web browser, and the iLife andiWork creativity and productivity suites. Its online services include the iTunes Store, theiOS App Store and Mac App Store, and iCloud.

Apple was founded by Steve Jobs, Steve Wozniak, and Ronald Wayne in April 1976 to develop and sell personal computers.It was incorporated as Apple Computer, Inc. in January 1977, and was renamed as Apple Inc. in January 2007 to reflect its shifted focus toward consumer electronics. Apple joined the Dow Jones Industrial Average in March 2015.

Apple is the world's largest information technology company by revenue, the world's largest technology company by total assets,and the world's second-largest mobile phone manufacturer.In November 2014, in addition to being the largest publicly traded corporation in the world by market capitalization, Apple became the first U.S. company to be valued at over US$700 billion.The company employs 115,000 permanent full-time employees as of July 2015 and maintains 478 retail stores in seventeen countries as of March 2016.It operates the online Apple Store and iTunes Store, the latter of which is the world's largest music retailer. There are over one billion actively used Apple products worldwide as of March 2016.

Apple's worldwide annual revenue totaled $233 billion for the fiscal year ending in September 2015.This revenue generation accounts for approximately 1.25% of the totalUnited States GDP.The company enjoys a high level of brand loyalty and, according toInterbrand's annual Best Global Brands report, has been the world's most valuable brand for 4 years in a row,with a valuation in 2016 of $178.1 billion.The corporationreceives significant criticism regarding the labor practices of its contractors and its environmental and business practices, including the origins of source materials.

In August 2016, after a three-year investigation by the EU's competition commissioner that concluded that Apple received "illegal state aid" from Ireland, the EU ordered Apple to pay 13 billion euros ($14.5 billion), plus interest, in unpaid taxes.

Google

Google is an American multinationaltechnology company specializing in Internet-related services and products that includeonline advertising technologies, s

earch, cloud computing, and software.Most of its profits are derived from AdWords, an online advertising service that places advertising near the list of search r

esults.

Google was founded by Larry Page andSergey Brin while they were Ph.D. students atStanford University, California. Together, they own about 14 percent of its shares and control 56 percent of the stockholder voting power through supervoting stock. They incorporated Google as a privately held company on September 4, 1998. An initial public offering (IPO) took place on August 19, 2004, and Google moved to its new headquarters in Mountain View, California, nicknamed the Googleplex.

In August 2015, Google announced plans to reorganize its interests as a holding companycalled Alphabet Inc. When this restructuring took place on October 2, 2015, Google became Alphabet's leading subsidiary, as well as the parent for Google's Internet interests.

Rapid growth since incorporation has triggered a chain of products, acquisitionsand partnerships beyond Google's core search engine (Google Search). It offers services designed for work and productivity (Google Docs, Sheets and Slides), email(Gmail), scheduling and time management (Google Calendar), cloud storage (Google Drive), social networking (Google+), instant messaging and video chat (Google Allo/Duo/Hangouts), language translation(Google Translate), mapping and turn-by-turn navigation (Google Maps), video-sharing (YouTube), taking notes (Google Keep), organizing and editing photos (Google Photos), and a web browser (Google Chrome). The company leads the development of theAndroid mobile operating system and the browser-only Chrome OS for a class ofnetbooks known as Chromebooks anddesktop PCs known as Chromeboxes. Google has moved increasingly into hardware; from 2010 to 2015, it partnered with major electronics manufacturers in the production of its "high-quality low-cost"Nexus devices,and in October 2016, it launched multiple hardware products (theGoogle Pixel, Home, Wifi, and Daydream View),with new hardware chief Rick Osterloh stating that "a lot of the innovation that we want to do now ends up requiring controlling the end-to-end user experience".In 2012, a fiber-optic infrastructure was installed in Kansas City to facilitate a Google Fiber broadband service.

Google has been estimated to run more than one million servers in data centers around the world (as of 2007).It processes over one billion search requests and about 24petabytes of user-generated data each day (as of 2009).In December 2013,Alexa listed Google.com as the most visited website in the world. Numerous Google sites in other languages figure in the top one hundred, as do several other Google-owned sites such as YouTube and Blogger.

Google's mission statement from the outset was "to organize the world's information and make it universally accessible and useful," and its unofficial slogan was "Don't be evil". In October 2015, the motto was replaced in the Alphabet corporate code of conduct by the phrase: "Do the right thing".Google's commitment to such robust idealism has been increasingly been called into doubt due to a number of actions and behaviours which appear to contradict this.