1.
Computer network
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A computer network or data network is a telecommunications network which allows nodes to share resources. In computer networks, networked computing devices exchange data with other using a data link. The connections between nodes are established using either cable media or wireless media, the best-known computer network is the Internet. Network computer devices that originate, route and terminate the data are called network nodes, nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices can be said to be networked together when one device is able to exchange information with the other device, Computer networks differ in the transmission medium used to carry their signals, communications protocols to organize network traffic, the networks size, topology and organizational intent. In most cases, application-specific communications protocols are layered over other more general communications protocols and this formidable collection of information technology requires skilled network management to keep it all running reliably. The chronology of significant computer-network developments includes, In the late 1950s, in 1960, the commercial airline reservation system semi-automatic business research environment went online with two connected mainframes. Licklider developed a group he called the Intergalactic Computer Network. In 1964, researchers at Dartmouth College developed the Dartmouth Time Sharing System for distributed users of computer systems. The same year, at Massachusetts Institute of Technology, a group supported by General Electric and Bell Labs used a computer to route. Throughout the 1960s, Leonard Kleinrock, Paul Baran, and Donald Davies independently developed network systems that used packets to transfer information between computers over a network, in 1965, Thomas Marill and Lawrence G. Roberts created the first wide area network. This was an precursor to the ARPANET, of which Roberts became program manager. Also in 1965, Western Electric introduced the first widely used telephone switch that implemented true computer control, in 1972, commercial services using X.25 were deployed, and later used as an underlying infrastructure for expanding TCP/IP networks. In July 1976, Robert Metcalfe and David Boggs published their paper Ethernet, Distributed Packet Switching for Local Computer Networks, in 1979, Robert Metcalfe pursued making Ethernet an open standard. In 1976, John Murphy of Datapoint Corporation created ARCNET, a network first used to share storage devices. In 1995, the transmission speed capacity for Ethernet increased from 10 Mbit/s to 100 Mbit/s, by 1998, Ethernet supported transmission speeds of a Gigabit. Subsequently, higher speeds of up to 100 Gbit/s were added, the ability of Ethernet to scale easily is a contributing factor to its continued use. Providing access to information on shared storage devices is an important feature of many networks, a network allows sharing of files, data, and other types of information giving authorized users the ability to access information stored on other computers on the network
2.
Embedded system
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An embedded system is a computer system with a dedicated function within a larger mechanical or electrical system, often with real-time computing constraints. It is embedded as part of a device often including hardware. Embedded systems control many devices in use today. Ninety-eight percent of all microprocessors are manufactured as components of embedded systems, examples of properties of typically embedded computers when compared with general-purpose counterparts are low power consumption, small size, rugged operating ranges, and low per-unit cost. This comes at the price of limited processing resources, which make them more difficult to program. For example, intelligent techniques can be designed to power consumption of embedded systems. Modern embedded systems are based on microcontrollers, but ordinary microprocessors are also common. In either case, the processor used may be ranging from general purpose to those specialised in certain class of computations. A common standard class of dedicated processors is the signal processor. Since the embedded system is dedicated to tasks, design engineers can optimize it to reduce the size and cost of the product and increase the reliability. Some embedded systems are mass-produced, benefiting from economies of scale, complexity varies from low, with a single microcontroller chip, to very high with multiple units, peripherals and networks mounted inside a large chassis or enclosure. One of the very first recognizably modern embedded systems was the Apollo Guidance Computer, an early mass-produced embedded system was the Autonetics D-17 guidance computer for the Minuteman missile, released in 1961. When the Minuteman II went into production in 1966, the D-17 was replaced with a new computer that was the first high-volume use of integrated circuits. Since these early applications in the 1960s, embedded systems have come down in price and there has been a rise in processing power. An early microprocessor for example, the Intel 4004, was designed for calculators and other systems but still required external memory. By the early 1980s, memory, input and output system components had been integrated into the chip as the processor forming a microcontroller. Microcontrollers find applications where a computer would be too costly. A comparatively low-cost microcontroller may be programmed to fulfill the role as a large number of separate components
3.
Twitter
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Twitter is an online news and social networking service where users post and interact with messages, tweets, restricted to 140 characters. Registered users can post tweets, but those who are unregistered can only read them, users access Twitter through its website interface, SMS or a mobile device app. Twitter Inc. is based in San Francisco, California, United States, Twitter was created in March 2006 by Jack Dorsey, Noah Glass, Biz Stone, and Evan Williams and launched in July. The service rapidly gained worldwide popularity, in 2012, more than 100 million users posted 340 million tweets a day, and the service handled an average of 1.6 billion search queries per day. In 2013, it was one of the ten most-visited websites and has described as the SMS of the Internet. As of 2016, Twitter had more than 319 million monthly active users. On the day of the 2016 U. S. presidential election, Twitter proved to be the largest source of breaking news, Twitters origins lie in a daylong brainstorming session held by board members of the podcasting company Odeo. Jack Dorsey, then a student at New York University. The original project name for the service was twttr, an idea that Williams later ascribed to Noah Glass, inspired by Flickr. The developers initially considered 10958 as a code, but later changed it to 40404 for ease of use. Work on the project started on March 21,2006, when Dorsey published the first Twitter message at 9,50 PM Pacific Standard Time, Dorsey has explained the origin of the Twitter title. we came across the word twitter, and it was just perfect. The definition was a short burst of inconsequential information, and chirps from birds, and thats exactly what the product was. The first Twitter prototype, developed by Dorsey and contractor Florian Weber, was used as a service for Odeo employees. Williams fired Glass, who was silent about his part in Twitters startup until 2011, Twitter spun off into its own company in April 2007. Williams provided insight into the ambiguity that defined this early period in a 2013 interview, With Twitter and they called it a social network, they called it microblogging, but it was hard to define, because it didnt replace anything. There was this path of discovery with something like that, where over time you figure out what it is, Twitter actually changed from what we thought it was in the beginning, which we described as status updates and a social utility. It is that, in part, but the insight we eventually came to was Twitter was really more of an information network than it is a social network, the tipping point for Twitters popularity was the 2007 South by Southwest Interactive conference. During the event, Twitter usage increased from 20,000 tweets per day to 60,000, the Twitter people cleverly placed two 60-inch plasma screens in the conference hallways, exclusively streaming Twitter messages, remarked Newsweeks Steven Levy
4.
Facebook
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Facebook is an American for-profit corporation and an online social media and social networking service based in Menlo Park, California. Facebook gradually added support for students at other universities. Since 2006, anyone age 13 and older has been allowed to become a user of Facebook, though variations exist in the minimum age requirement. The Facebook name comes from the face book directories often given to United States university students, Facebook may be accessed by a large range of desktops, laptops, tablet computers, and smartphones over the Internet and mobile networks. After registering to use the site, users can create a user profile indicating their name, occupation, schools attended and so on. Additionally, users may join common-interest user groups organized by workplace, school, hobbies or other topics, in groups, editors can pin posts to top. Additionally, users can complain about or block unpleasant people, because of the large volume of data that users submit to the service, Facebook has come under scrutiny for its privacy policies. Facebook makes most of its revenue from advertisements which appear onscreen, Facebook, Inc. held its initial public offering in February 2012, and began selling stock to the public three months later, reaching an original peak market capitalization of $104 billion. On July 13,2015, Facebook became the fastest company in the Standard & Poors 500 Index to reach a market cap of $250 billion, Facebook has more than 1.86 billion monthly active users as of December 31,2016. As of April 2016, Facebook was the most popular social networking site in the world, Facebook classifies users from the ages of 13 to 18 as minors and therefore sets their profiles to share content with friends only. Zuckerberg wrote a program called Facemash on October 28,2003 while attending Harvard University as a sophomore, to accomplish this, Zuckerberg hacked into protected areas of Harvards computer network and copied private dormitory ID images. Facemash attracted 450 visitors and 22,000 photo-views in its first four hours online, the site was quickly forwarded to several campus group list-servers, but was shut down a few days later by the Harvard administration. Zuckerberg faced expulsion and was charged by the administration with breach of security, violating copyrights, Zuckerberg expanded on this initial project that semester by creating a social study tool ahead of an art history final exam. He uploaded 500 Augustan images to a website, each of which was featured with a corresponding comments section and he shared the site with his classmates, and people started sharing notes. The following semester, Zuckerberg began writing code for a new website in January 2004 and he said that he was inspired by an editorial about the Facemash incident in The Harvard Crimson. On February 4,2004, Zuckerberg launched Thefacebook, originally located at thefacebook. com. com and they claimed that he was instead using their ideas to build a competing product. The three complained to The Harvard Crimson and the newspaper began an investigation and they later filed a lawsuit against Zuckerberg, subsequently settling in 2008 for 1.2 million shares. Membership was initially restricted to students of Harvard College, within the first month, eduardo Saverin, Dustin Moskovitz, Andrew McCollum, and Chris Hughes joined Zuckerberg to help promote the website
5.
Linux
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Linux is a Unix-like computer operating system assembled under the model of free and open-source software development and distribution. The defining component of Linux is the Linux kernel, an operating system kernel first released on September 17,1991 by Linus Torvalds, the Free Software Foundation uses the name GNU/Linux to describe the operating system, which has led to some controversy. Linux was originally developed for computers based on the Intel x86 architecture. Because of the dominance of Android on smartphones, Linux has the largest installed base of all operating systems. Linux is also the operating system on servers and other big iron systems such as mainframe computers. It is used by around 2. 3% of desktop computers, the Chromebook, which runs on Chrome OS, dominates the US K–12 education market and represents nearly 20% of the sub-$300 notebook sales in the US. Linux also runs on embedded systems – devices whose operating system is built into the firmware and is highly tailored to the system. This includes TiVo and similar DVR devices, network routers, facility automation controls, televisions, many smartphones and tablet computers run Android and other Linux derivatives. The development of Linux is one of the most prominent examples of free, the underlying source code may be used, modified and distributed—commercially or non-commercially—by anyone under the terms of its respective licenses, such as the GNU General Public License. Typically, Linux is packaged in a known as a Linux distribution for both desktop and server use. Distributions intended to run on servers may omit all graphical environments from the standard install, because Linux is freely redistributable, anyone may create a distribution for any intended use. The Unix operating system was conceived and implemented in 1969 at AT&Ts Bell Laboratories in the United States by Ken Thompson, Dennis Ritchie, Douglas McIlroy, first released in 1971, Unix was written entirely in assembly language, as was common practice at the time. Later, in a key pioneering approach in 1973, it was rewritten in the C programming language by Dennis Ritchie, the availability of a high-level language implementation of Unix made its porting to different computer platforms easier. Due to an earlier antitrust case forbidding it from entering the computer business, as a result, Unix grew quickly and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of Bell Labs, freed of the legal obligation requiring free licensing, the GNU Project, started in 1983 by Richard Stallman, has the goal of creating a complete Unix-compatible software system composed entirely of free software. Later, in 1985, Stallman started the Free Software Foundation, by the early 1990s, many of the programs required in an operating system were completed, although low-level elements such as device drivers, daemons, and the kernel were stalled and incomplete. Linus Torvalds has stated that if the GNU kernel had been available at the time, although not released until 1992 due to legal complications, development of 386BSD, from which NetBSD, OpenBSD and FreeBSD descended, predated that of Linux. Torvalds has also stated that if 386BSD had been available at the time, although the complete source code of MINIX was freely available, the licensing terms prevented it from being free software until the licensing changed in April 2000
6.
Android (operating system)
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Android is a mobile operating system developed by Google, based on the Linux kernel and designed primarily for touchscreen mobile devices such as smartphones and tablets. In addition to devices, Google has further developed Android TV for televisions, Android Auto for cars. Variants of Android are also used on notebooks, game consoles, digital cameras, beginning with the first commercial Android device in September 2008, the operating system has gone through multiple major releases, with the current version being 7.0 Nougat, released in August 2016. Android applications can be downloaded from the Google Play store, which features over 2.7 million apps as of February 2017, Android has been the best-selling OS on tablets since 2013, and runs on the vast majority of smartphones. In September 2015, Android had 1.4 billion monthly active users, Android is popular with technology companies that require a ready-made, low-cost and customizable operating system for high-tech devices. The success of Android has made it a target for patent, Android Inc. was founded in Palo Alto, California in October 2003 by Andy Rubin, Rich Miner, Nick Sears, and Chris White. Rubin described the Android project as tremendous potential in developing smarter mobile devices that are aware of its owners location. The early intentions of the company were to develop an operating system for digital cameras. Despite the past accomplishments of the founders and early employees, Android Inc. operated secretly and that same year, Rubin ran out of money. Steve Perlman, a friend of Rubin, brought him $10,000 in cash in an envelope. In July 2005, Google acquired Android Inc. for at least $50 million and its key employees, including Rubin, Miner and White, joined Google as part of the acquisition. Not much was known about Android at the time, with Rubin having only stated that they were making software for mobile phones, at Google, the team led by Rubin developed a mobile device platform powered by the Linux kernel. Google marketed the platform to handset makers and carriers on the promise of providing a flexible, upgradeable system, Google had lined up a series of hardware components and software partners and signaled to carriers that it was open to various degrees of cooperation. Speculation about Googles intention to enter the communications market continued to build through December 2006. In September 2007, InformationWeek covered an Evalueserve study reporting that Google had filed several patent applications in the area of mobile telephony, the first commercially available smartphone running Android was the HTC Dream, also known as T-Mobile G1, announced on September 23,2008. Since 2008, Android has seen numerous updates which have improved the operating system, adding new features. Each major release is named in order after a dessert or sugary treat, with the first few Android versions being called Cupcake, Donut, Eclair. In 2010, Google launched its Nexus series of devices, a lineup in which Google partnered with different device manufacturers to produce new devices and introduce new Android versions
7.
Symbian
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Symbian is a discontinued mobile operating system and computing platform designed for smartphones. Symbian was originally developed as a closed-source OS for PDAs in 1998 by Symbian Ltd, Symbian OS was a descendant of Psions EPOC, and runs exclusively on ARM processors, although an unreleased x86 port existed. Symbian was used by major mobile phone brands, like Samsung, Motorola, Sony Ericsson. Symbian OS was essentially a system and required an additional user interface to form a complete operating system. Symbian OS became prominent from the S60 platform built by Nokia, first released in 2002, Symbian eventually became the most widely used smart mobile operating system. UIQ was another Symbian user interface used by Motorola and Sony Ericsson. Applications of these interfaces were not compatible with other, despite each being built atop Symbian OS. Nokia was the majority shareholder in Symbian Ltd. and purchased the entire share in 2008, the non-profit Symbian Foundation was then created to make a royalty-free successor to Symbian OS - seeking to unify the platform, S60 became the Foundations favoured UI and UIQ stopped development. Symbian^1 was created as a result in 2009, Symbian^2 was only used by carrier NTT DoCoMo, one of the members of the Foundation, for the Japanese market. Symbian^3 was released as in 2010, by time it became fully open source. Symbian^3 received the Anna and Belle updates in 2011, the Symbian Foundation disintegrated in late 2010 and Nokia took back control of the OS development. Two months later, Nokia moved the OS to closed licensing, and later outsourced Symbian development to Accenture. Although support was promised until 2016, there was little development from Accenture, in January 2014, Nokia stopped accepting new or changed Symbian software from developers. The Nokia 808 PureView was officially the last Symbian smartphone from Nokia, however NTT DoCoMo continued releasing OPP devices in Japan, which still act as middleware on top of Symbian. Phones running this include the F-07F（Japanese：--） from Fujitsu and SH-07F（Japanese：--） from Sharp in 2014, Symbian originated from EPOC32, an operating system created by Psion in the 1990s. In June 1998, Psion Software became Symbian Ltd. a major joint venture between Psion and phone manufacturers Ericsson, Motorola, and Nokia, afterwards, different software platforms were created for Symbian, backed by different groups of mobile phone manufacturers. They include S60, UIQ and MOAP, with no major competition in the smartphone OS then, Symbian reached as high as 67% of the global smartphone market share in 2006. All of this discouraged third-party developers, and served to cause the native app ecosystem for Symbian not to evolve to a scale later reached by Apples App Store or Androids Google Play
8.
Computer hardware
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Computer hardware is the collection of physical components that constitute a computer system. By contrast, software is instructions that can be stored and run by hardware, hardware is directed by the software to execute any command or instruction. A combination of hardware and software forms a usable computing system, the template for all modern computers is the Von Neumann architecture, detailed in a 1945 paper by Hungarian mathematician John von Neumann. The meaning of the term has evolved to mean a stored-program computer in which an instruction fetch and this is referred to as the Von Neumann bottleneck and often limits the performance of the system. For the third year, U. S. business-to-business channel sales increased. The impressive growth was the fastest sales increase since the end of the recession, sales growth accelerated in the second half of the year peaking in fourth quarter with a 6.9 percent increase over the fourth quarter of 2012. There are a number of different types of system in use today. The personal computer, also known as the PC, is one of the most common types of computer due to its versatility, laptops are generally very similar, although they may use lower-power or reduced size components, thus lower performance. The computer case is a plastic or metal enclosure that houses most of the components, a case can be either big or small, but the form factor of motherboard for which it is designed matters more. A power supply unit converts alternating current electric power to low-voltage DC power for the components of the computer. Laptops are capable of running from a battery, normally for a period of hours. The motherboard is the component of a computer. It is usually cooled by a heatsink and fan, or water-cooling system, most newer CPUs include an on-die Graphics Processing Unit. The clock speed of CPUs governs how fast it executes instructions, many modern computers have the option to overclock the CPU which enhances performance at the expense of greater thermal output and thus a need for improved cooling. The chipset, which includes the bridge, mediates communication between the CPU and the other components of the system, including main memory. Random-Access Memory, which stores the code and data that are being accessed by the CPU. For example, when a web browser is opened on the computer it takes up memory, RAM usually comes on DIMMs in the sizes 2GB, 4GB, and 8GB, but can be much larger. Read-Only Memory, which stores the BIOS that runs when the computer is powered on or otherwise begins execution, the BIOS includes boot firmware and power management firmware
9.
Web browser
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A web browser is a software application for retrieving, presenting and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier that may be a web page, image, hyperlinks present in resources enable users easily to navigate their browsers to related resources. Although browsers are primarily intended to use the World Wide Web, the most popular web browsers are Google Chrome, Microsoft Edge, Safari, Opera and Firefox. The first web browser was invented in 1990 by Sir Tim Berners-Lee, Berners-Lee is the director of the World Wide Web Consortium, which oversees the Webs continued development, and is also the founder of the World Wide Web Foundation. His browser was called WorldWideWeb and later renamed Nexus, the first commonly available web browser with a graphical user interface was Erwise. The development of Erwise was initiated by Robert Cailliau, andreesens browser sparked the internet boom of the 1990s. The introduction of Mosaic in 1993 – one of the first graphical web browsers – led to an explosion in web use, Microsoft responded with its Internet Explorer in 1995, also heavily influenced by Mosaic, initiating the industrys first browser war. Bundled with Windows, Internet Explorer gained dominance in the web browser market, Internet Explorer usage share peaked at over 95% by 2002. Opera debuted in 1996, it has never achieved widespread use and it is also available on several other embedded systems, including Nintendos Wii video game console. In 1998, Netscape launched what was to become the Mozilla Foundation in an attempt to produce a competitive browser using the open source software model, as of August 2011, Firefox has a 28% usage share. Apples Safari had its first beta release in January 2003, as of April 2011, the most recent major entrant to the browser market is Chrome, first released in September 2008. Chromes take-up has increased year by year, by doubling its usage share from 8% to 16% by August 2011. This increase seems largely to be at the expense of Internet Explorer, in December 2011, Chrome overtook Internet Explorer 8 as the most widely used web browser but still had lower usage than all versions of Internet Explorer combined. Chromes user-base continued to grow and in May 2012, Chromes usage passed the usage of all versions of Internet Explorer combined, by April 2014, Chromes usage had hit 45%. Internet Explorer was deprecated in Windows 10, with Microsoft Edge replacing it as the web browser. The ways that web browser makers fund their development costs has changed over time, the first web browser, WorldWideWeb, was a research project. In addition to being freeware, Netscape Navigator and Opera were also sold commercially, Internet Explorer, on the other hand, was bundled free with the Windows operating system, and therefore it was funded partly by the sales of Windows to computer manufacturers and direct to users. Internet Explorer also used to be available for the Mac, in this respect, IE may have contributed to Windows and Microsoft applications sales in another way, through lock-in to Microsofts browser
10.
WebOS
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WebOS, also known as Open WebOS or LG WebOS, is a Linux kernel-based multitask operating system for smart devices such as Smart TVs and it has been used as a mobile operating system. Initially developed by Palm, HP made the open source. The operating system was sold to LG Electronics. HP still held patents related to WebOS. In January 2014, Qualcomm announced that it had acquired technology patents from HP, various versions of WebOS have been featured on several devices, including Pre, Pixi, and Veer smartphones, TouchPad tablet, LG Smart TVs since 2015. Palm launched WebOS, then called Palm WebOS, in January 2009 as the successor to Palm OS, the first WebOS device was the original Palm Pre, released by Sprint in June 2009. Upgraded Plus versions of both Pre and Pixi were released on Verizon and AT&T, in April 2010 HP acquired Palm, WebOS was described by Leo Apotheker as a key asset and motivation for the purchase. The $1.2 billion acquisition finalized in June, HP indicated its intention to develop the WebOS platform for use in multiple new products, including smartphones, tablets, and printers. In February 2011, HP announced that it would use WebOS as the platform for all its devices. HP announced several WebOS devices, including the HP Veer and HP Pre 3 smartphones, running WebOS2.2, and the HP TouchPad, a tablet computer released in July 2011 that runs WebOS3.0. In March 2011 HP announced plans for a version of WebOS by the end of 2011 to run within Windows, and to be installed on all HP desktop and notebook computers in 2012. Neither ever materialized, although work had begun on an x86 port around this time involving a team in Fort Collins, Colorado and it remained unclear whether HP would consider licensing WebOS software to other manufacturers. When HP reduced the price of the Touchpad to $99, the inventory quickly sold out. Notably, these US Pre 3 units, having been released through unofficial channels, the last HP WebOS version,3.0.5, was released on 12 January 2012. In August 2012, code specific to the devices was released as WebOS Community Edition. Open WebOS includes open source libraries designed to target a range of hardware. HP renamed its WebOS unit as Gram, in February 2012 HP released Isis, a new web browser for Open WebOS. The HP App Catalog was an app store for apps for the devices running WebOS
