Tablet computer

History

The tablet computer and its associated operating system began with the development of pen computing. Electrical devices with data input and output on a flat information display existed as early as 1888 with the telautograph, which used a sheet of paper as display and a pen attached to electromechanical actuators. Throughout the 20th century devices with these characteristics have been imagined and created whether as blueprints, prototypes, or commercial products. In addition to many academic and research systems, several companies released commercial products in the 1980s, with various input/output types tried out:

Fictional and prototype tablets

Tablet computers appeared in a number of works of science fiction in the second half of the 20th century; all helped to promote and disseminate the concept to a wider audience. Examples include:

A device more powerful than today's tablets appeared briefly in Jerry Pournelle and Larry Niven's The Mote in God's Eye (1974).

Additionally, real-life projects either proposed or created tablet computers, such as:

Early tablets

Following earlier tablet-computer products such as the Pencept PenPad, and the CIC Handwriter, in September 1989, GRiD Systems released the first commercially successful tablet-type portable computer, the GRiDPad. All three products were based on extended versions of the MS-DOS operating system. In 1992, IBM announced (in April) and shipped to developers (in October) the 2521 ThinkPad, which ran the GO Corporation's PenPoint OS. Also based on PenPoint was AT&T's EO Personal Communicator from 1993, which ran on AT&T's own hardware, including their own AT&T Hobbit CPU. Apple Computer launched the Apple Newton personal digital assistant in 1993. It utilised Apple's own new Newton OS, initially running on hardware manufactured by Motorola and incorporating an ARM CPU, that Apple had specifically co-developed with Acorn Computers. The operating system and platform design were later licensed to Sharp and Digital Ocean, who went on to manufacture their own variants.

In 1996, Palm, Inc. released the first of the Palm OS based PalmPilot touch and stylus based PDA, the touch based devices initially incorporating a Motorola Dragonball (68000) CPU. Also in 1996 Fujitsu released the Stylistic 1000 tablet format PC, running Microsoft Windows 95, on a 100 MHz AMD486 DX4 CPU, with 8 MB RAM offering stylus input, with the option of connecting a conventional Keyboard and mouse. Intel announced a StrongARM processor-based touchscreen tablet computer in 1999, under the name WebPAD. It was later re-branded as the "Intel Web Tablet". In 2000, Norwegian company Screen Media AS and the German company Dosch & Amand Gmbh released the " FreePad". It was based on Linux and used the Opera browser. Internet access was provided by DECT DMAP, only available in Europe and provided up to 10Mbit/s. The device had 16 MB storage, 32 MB of RAM and x86 compatible 166 MHz "Geode"-Microcontroller by National Semiconductor. The screen was 10.4" or 12.1" and was touch sensitive. It had slots for SIM cards to enable support of television set-up box. FreePad were sold in Norway and the Middle East; but the company was dissolved in 2003.

In April 2000, Microsoft launched the Pocket PC 2000, utilizing their touch capable Windows CE 3.0 operating system. The devices were manufactured by several manufacturers, based on a mix of: x86, MIPS, ARM, and SuperH hardware. In 2002, Microsoft attempted to define the Microsoft Tablet PC as a mobile computer for field work in business, though their devices failed, mainly due to pricing and usability decisions that limited them to their original purpose - such as the existing devices being too heavy to be held with one hand for extended periods, and having legacy applications created for desktop interfaces and not well adapted to the slate format.

Nokia had plans for an Internet tablet since before 2000. An early model was test manufactured in 2001, the Nokia M510, which was running on EPOC and featuring an Opera browser, speakers and a 10-inch 800×600 screen, but it was not released because of fears that the market was not ready for it. In 2005, Nokia finally released the first of its Internet Tablet range, the Nokia 770. These tablets now ran a Debian based Linux OS called Maemo. Nokia used the term internet tablet to refer to a portable information appliance that focused on Internet use and media consumption, in the range between a personal digital assistant (PDA) and an Ultra-Mobile PC (UMPC). They made two mobile phones, the N900 that runs Maemo, and N9 that run Meego. Before the release of iPad, Axiotron introduced an aftermarket, heavily modified Apple MacBook called Modbook, a Mac OS X-based tablet computer. The Modbook uses Apple's Inkwell for handwriting and gesture recognition, and uses digitization hardware from Wacom. To get Mac OS X to talk to the digitizer on the integrated tablet, the Modbook was supplied with a third-party driver.

Android was the first of the 2000s-era dominating platforms for tablet computers to reach the market. In 2008, the first plans for Android-based tablets appeared. The first products were released in 2009. Among them was the Archos 5, a pocket-sized model with a 5-inch touchscreen, that was first released with a proprietary operating system and later (in 2009) released with Android 1.4. The Camangi WebStation was released in Q2 2009. The first LTE Android tablet appeared late 2009 and was made by ICD for Verizon. This unit was called the Ultra, but a version called Vega was released around the same time. Ultra had a 7-inch display while Vega's was 15 inches. Many more products followed in 2010. Several manufacturers waited for Android Honeycomb, specifically adapted for use with tablets, which debuted in February 2011.

Modern tablets

Apple is often credited for defining a new class of consumer device with the iPad, which shaped the commercial market for tablets in the following years, and was the most successful tablet at the time of its release. iPads and competing devices were tested by the US military in 2011 and cleared for secure use in 2013. Its debut in 2010 pushed tablets into the mainstream. Samsung's Galaxy Tab and others followed, continuing the trends towards the features listed above. In March 2012, PC Magazine reported that 31% of U.S. Internet users owned a tablet, used mainly for viewing published content such as video and news. The top-selling line of devices was Apple's iPad with 100 million sold between its release in April 2010 and mid-October 2012, but iPad market share (number of units) dropped to 36% in 2013 with Android tablets climbing to 62%. Android tablet sales volume was 121 million devices, plus 52 million, between 2012 and 2013 respectively. Individual brands of Android operating system devices or compatibles follow iPad with Amazon's Kindle Fire with 7 million, and Barnes & Noble's Nook with 5 million.

As of February 2014, 83% of mobile app developers were targeting tablets, but 93% of developers were targeting smartphones. By 2014 around 23% of B2B companies were said to have deployed tablets for sales-related activities, according to a survey report by Corporate Visions. The iPad holds majority use in North America, Western Europe, Japan, Australia, and most of the Americas. Android tablets are more popular in most of Asia (China and Russia an exception), Africa and Eastern Europe. In 2015 tablet sales did not increase. Apple remained the largest seller but its market share declined below 25%. Samsung vice president Gary Riding said early in 2016 that tablets were only doing well among those using them for work. Newer models were more expensive and designed for a keyboard and stylus, which reflected the changing uses. As of early 2016, Android reigns over the market with 65%. Apple takes the number 2 spot with 26%, and Windows take a distant third with the remaining 9%.

Types

Tablets can be loosely grouped into several categories, by physical size, operating system installed, input/output technology and usage.

Slate

A slate's size may vary, starting from 6 inches (approximately 15 cm). Some models in the larger than 10-inch category include the Samsung Galaxy Tab Pro 12.2 at 12.2 inches, the Toshiba Excite at 13.3 inches and the Dell XPS 18 at 18.4 inches. As of March 2013, the thinnest tablet on the market was the Sony Xperia Tablet Z at only 0.27 inches (6.9 mm) thick. On 9 September 2015, Apple released the iPad Pro with a 12.9 inches (33 cm) screen size, larger than the regular iPad.

Mini tablet

Mini tablets are smaller and lighter than standard slates, with a typical screen size between 7–8 inches (18–20 cm). The first successful ones were introduced by Amazon (Kindle Fire), Barnes & Noble (Nook Tablet), and Samsung (7-inch Galaxy Tab) in 2011, and by Google (the Nexus 7) in 2012. They work the same as larger tablets, however with lower specifications when compared to the larger tablets. On September 14, 2012, Amazon released an upgraded version of the Kindle Fire, called the Kindle Fire HD, with higher resolution and more features compared with the original Kindle Fire, though it remained 7 inches. In October 2012, Apple released the iPad Mini with a 7.9 inch screen size, about 2 inches smaller than the regular iPad, but less powerful than the then current iPad 3. On July 24, 2013, Google released an upgraded version of the Nexus 7, with FHD display, dual cameras, stereo speakers, more color accuracy, performance improvement, built-in wireless charging, and a variant with 4G LTE support for AT&T, T-Mobile, and Verizon. In September 2013, Amazon further updated the Fire tablet with the Kindle Fire HDX. In November 2013, Apple released the iPad Mini 2, which remained at 7.9 inches and nearly matched the hardware of the iPad Air.

Phablet

Since 2010, crossover touch-screen mobile phones with screens larger than 5-inches have been released. That size is generally considered larger than a traditional smartphone, creating a hybrid category called a phablet by Engadget and Forbes. Phablet is a portmanteau of phone and tablet. Examples of phablets are the Dell Streak, LG Optimus Vu, and Samsung Galaxy Note. Samsung announced they had shipped a million units of the Galaxy Note within two months of introducing it.

Convertibles and hybrids are crossover devices, featuring traits of both tablets and laptops. Convertibles have a chassis design allowing to conceal the keyboard, for example folding it behind the chassis. Hybrids' keyboards can be completely detached even when the device is running. 2-in-1s can have either the convertible or hybrid form, dubbed 2-in-1 convertibles and 2-in-1 detachables respectively, but distinct by support of desktop operating system, such as Windows 10. When traditional tablets are primarily used as a media consumption devices, 2-in-1s capable of both that and a content creation. For this reason they are often dubbed as a laptop or desktop replacement computers.

2-in-1s have a number of typical laptop I/O-ports, such as USB 3 and DisplayPort, run desktop operating system, like Windows 10, and can connect to a number of traditional PC peripheral devices and external displays. Asus Transformer Pad-series devices, which run variants of Android OS, are example of hybrids. The latest addition to the Apple iPad series, iPad Pro with an optional detachable keyboard and a stylus is a prominent example of a modern hybrid. Microsoft's Surface Pro-series devices and Surface Book exemplify 2-in-1 detachables, whereas Lenovo Yoga-series computers are notable 2-in-1 convertibles.

Gaming tablet

Some tablets are modified by adding physical gamepad buttons such as D-pad and thumb sticks for better gaming experience combined with the touchscreen and all other features of a typical tablet computer. Most of these tablets are targeted to run native OS games and emulator games. Nvidia's Shield Tablet, with a 8 inches (200 mm) display, and running Android, is an example. It runs Android games purchased from Google Play store. PC games can also be streamed to the tablet from computers with some higher end models of Nvidia-powered video cards. The Nintendo Switch console is a gaming tablet.

Booklet

Booklets are dual-touchscreen tablet computers with a clamshell design that can fold like a laptop. Examples include the Microsoft Courier, which was discontinued in 2010, the Sony Tablet P (which was considered a flop), and the Toshiba Libretto W100.

Customized business tablet

Customized business tablets are built specifically for a business customer's particular needs from a hardware and software perspective, and delivered in a business-to-business transaction. For example, in hardware, a transportation company may find that the consumer-grade GPS module in an off-the-shelf tablet provides insufficient accuracy, so a tablet can be customized and embedded with a professional-grade antenna to provide a better GPS signal. Such tablets may also be ruggedized for field use. For a software example, the same transportation company might remove certain software functions in the Android system, such as the internet browser, to reduce costs from unnecessary cellular network data consumption of an employee, and add custom package management software. Other applications may call for a resistive touchscreen and other special hardware and software.

System architecture

Two major architectures dominate the tablet market, ARM Holdings' ARM architecture and Intel's and AMD's x86. Intel's x86, including x86-64 has powered the "IBM compatible" PC since 1981 and Apple's Macintosh computers since 2006. The CPUs have been incorporated into tablet PCs over the years and generally offer greater performance along with the ability to run full versions of Microsoft Windows, along with Windows desktop and enterprise applications. Non-Windows based x86 tablets include the JooJoo. Intel announced plans to enter the tablet market with its Atom in 2010. In October 2013, Intel's foundry operation announced plans to build FPGA-based quad cores for ARM and x86 processors.

ARM has been the CPU architecture of choice for manufacturers of smartphones (95% ARM), PDAs, digital cameras (80% ARM), set-top boxes, DSL routers, smart televisions (70% ARM), storage devices and tablet computers (95% ARM). This dominance began with the release of the mobile-focused and comparatively power-efficient 32-bit ARM610 processor originally designed for the Apple Newton in 1993 and ARM3-using Acorn A4 laptop in 1992. The chip was adopted by Psion, Palm and Nokia for PDAs and later smartphones, camera phones, cameras, etc. ARM's licensing model supported this success by allowing device manufacturers to license, alter and fabricate custom SoC derivatives tailored to their own products. This has helped manufacturers extend battery life and shrink component count along with the size of devices.

The multiple licensees ensured that multiple fabricators could supply near-identical products, while encouraging price competition. This forced unit prices down to a fraction of their x86 equivalents. The architecture has historically had limited support from Microsoft, with only Windows CE available, but with the 2012 release of Windows 8, Microsoft announced additional support for the architecture, shipping their own ARM-based tablet computer, branded the Microsoft Surface, as well as an x86-64 Intel Core i5 variant branded as Microsoft Surface Pro. Intel tablet chip sales were 1 million units in 2012, and 12 million units in 2013. Intel chairman Andy Bryant has stated that its 2014 goal is to quadruple its tablet chip sales to 40 million units by the end of that year, as an investment for 2015.

Display

A key component among tablet computers is touch input on a touchscreen display. This allows the user to navigate easily and type with a virtual keyboard on the screen or press other icons on the screen to open apps or files. The first tablet to do this was the GRiDPad by GRiD Systems Corporation; the tablet featured both a stylus, a pen-like tool to aid with precision in a touchscreen device as well as an on-screen keyboard. The system must respond to on-screen touches rather than clicks of a keyboard or mouse. This operation makes precise use of our eye–hand coordination.

Touchscreens usually come in one of two forms:

Since mid 2010s, most tablets use capacitive touchscreens with multi-touch, unlike earlier resistive touchscreen devices which users needed styluses to do input.

Handwriting recognition

Some ARM powered tablets, such as the Galaxy Note 10, support a stylus and support handwriting recognition. Wacom and N-trig digital pens provide approximately 2500 DPI resolution for handwriting, exceeding the resolution of capacitive touch screens by more than a factor of 10. These pens also support pressure sensitivity, allowing for "variable-width stroke-based" characters, such as Chinese/Japanese/Korean writing, due to their built-in capability of "pressure sensing". Pressure is also used in digital art applications such as Autodesk Sketchbook. Apps exist on both iOS and Android platforms for handwriting recognition and in 2015 Google introduced its own handwriting input with support for 82 languages.

Other features

After 2007, with access to capacitive screens and the success of the iPhone, other features became common, such as multi-touch features (in which the user can touch the screen in multiple places to trigger actions and other natural user interface features, as well as flash memory solid state storage and "instant on" warm-booting; external USB and Bluetooth keyboards defined tablets. Some tablets have 3G mobile telephony applications.

Most tablets released since mid-2010 use a version of an ARM processor for longer battery life. The ARM Cortex family is powerful enough for tasks such as internet browsing, light production work and mobile games.

Other features are, High-definition, anti-glare display, Touchscreen, Front- and/or back- facing camera(s) for photographs and video, Lower weight and longer battery life than a comparably-sized laptop, Wireless local area and internet connectivity (usually with Wi-Fi standard and optional mobile broadband), Bluetooth for connecting peripherals and communicating with local devices, Ports for wired connections and charging, for example USB ports, Early devices had IR support and could work as a TV remote controller, Docking station: Keyboard and additional connections, On-board flash memory, Ports for removable storage, Various cloud storage services for backup and syncing data across devices, Local storage on a LAN

Besides a touchscreen and keyboard, many tablets can also use these input methods:

Operating system

Tablets, like conventional PCs, run on multiple operating systems (though dual-booting on tablets is relatively rare). These operating systems come in two classes, desktop-based and mobile-based ("phone-like") OS. Desktop OS-based tablets are currently thicker and heavier, require more storage, more cooling and give less battery life, but can run processor-intensive applications such as Adobe Photoshop in addition to mobile apps and have more ports, while mobile-based tablets are the reverse, only run mobile apps. Those that focus more so on mobile apps use battery life conservatively because the processor is significantly smaller. This allows the battery to last much longer than the common laptop. At the end of Q1 2013, GlobalWebIndex noted that in two years tablet usage increased by 282 percent, with 156 million Android tablet users and 122 million iPad users making up 75 percent. By year-end 2013, Gartner found that 121 million (plus 53M in 2012) Android tablets, 70 million (plus 61M in 2012) iOS tablets, and 4 million (plus 1M in 2012) Windows tablets had been sold to end-users (2013 and 2012 results). In early 2016 Android tablets had 65% of the market, Apple's iOS had 26% of the market and Windows 10 had 9% of the market.

Android

Android is a Linux-based operating system that Google offers as open source under the Apache license. It is designed primarily for mobile devices such as smartphones and tablet computers. Android supports low-cost ARM systems and others. Many such systems were announced in 2010. Vendors such as Motorola and Lenovo delayed deployment of their tablets until after 2011, when Android was reworked to include more tablet features. Android 3.0 (Honeycomb) and later versions support larger screen sizes, mainly tablets, and have access to the Google Play service. Android includes operating system, middleware and key applications. Other vendors sell customized Android tablets, such as Kindle Fire and Nook, which are used to consume mobile content and provide their own app store, rather than using the larger Google Play system, thereby fragmenting the Android market. Hardware makers that have shipped Android tablets include Acer, Asus, Lenovo, Samsung, Sony, and Toshiba. Additionally, Google introduced the Nexus 7 and Nexus 10 tablets in 2012.

iOS

The iPad runs on iOS, which was created for the iPhone and iPod Touch. Although built on the same underlying Unix implementation as MacOS, its user interface is radically different. iOS is designed for fingers and has none of the features that required a stylus on earlier tablets. Apple introduced multi-touch gestures, such as moving two fingers apart or together to zoom in or out, also known as "pinch to zoom". iOS is built for the ARM architecture.

Windows

Following Windows for Pen Computing for Windows 3.1 in 1991, Microsoft supported tablets running Windows XP under the Microsoft Tablet PC name. Microsoft Tablet PCs were pen-based, fully functional x86 PCs with handwriting and voice recognition functionality. Windows XP Tablet PC Edition provided pen support. Tablet support was added to both Home and Business versions of Windows Vista and Windows 7. Tablets running Windows could use the touchscreen for mouse input, hand writing recognition and gesture support. Following Tablet PC, Microsoft announced the Ultra-mobile PC initiative in 2006 which brought Windows tablets to a smaller, touch-centric form factor. In 2008, Microsoft showed a prototype of a two-screen tablet called Microsoft Courier, but cancelled the project.

In 2012, Microsoft released Windows 8, which features significant changes to various aspects of the operating system's user interface and platform which are designed for touch-based devices such as tablets. The operating system also introduced an application store and a new style of application optimized primarily for use on tablets. Microsoft also introduced Windows RT, an edition of Windows 8 for use on ARM-based devices. The launch of Windows 8 and RT was accompanied by the release of devices with the two operating systems by various manufacturers (including Microsoft themselves, with the release of Surface), such as slate tablets, hybrids, and convertibles. Windows RT was discontinued in 2014.

Released in July 2015, Windows 10 introduces what Microsoft described as "universal apps"; expanding on Metro-style apps, these apps can be designed to run across multiple Microsoft product families with nearly identical code‍—‌including PCs, tablets, smartphones, embedded systems, Xbox One, Surface Hub and Windows Holographic. The Windows user interface was revised to handle transitions between a mouse-oriented interface and a touchscreen-optimized interface based on available input devices‍—‌particularly on 2-in-1 PCs; both interfaces include an updated Start menu which incorporates elements of Windows 7's traditional Start menu with the tiles of Windows 8.

Ubuntu Touch

Ubuntu uses the Unity UI. Canonical hinted that Ubuntu would be available on tablets by 2014. In February 2016 there was a commercial release of an Ubuntu tablet. TabletKiosk was the first to offer a hybrid digitizer / touch device running openSUSE Linux.

Hybrid OS operation

Several hardware companies have built hybrid devices with the possibility to work with both the Windows 10 and Android operating systems.

Discontinued operating systems

BlackBerry Tablet OS

The BlackBerry PlayBook is a tablet computer announced in September 2010 that runs the BlackBerry Tablet OS. The OS is based on the QNX system that Research in Motion acquired in early 2010. The BlackBerry PlayBook was officially released to US and Canadian consumers on April 19, 2011. As of 2014, Playbook is not available on sale on any Blackberry websites.

Firefox OS

Firefox OS is an open-source operating system based on Linux and the Firefox web browser, targeting low-end smartphones, tablet computers and smart TV devices. In 2013, the Mozilla Foundation started a prototype tablet model with Foxconn. Firefox OS was discontinued in 2016.

WebOS

Hewlett Packard announced that the TouchPad, running WebOS 3.0 on a 1.2 GHz Qualcomm Snapdragon CPU, would be released in June 2011. On August 18, 2011, HP announced the discontinuation of the TouchPad, due to sluggish sales. In February 2013, HP announced they had sold WebOS to LG Electronics.

MeeGo/Maemo/Moblin

Nokia entered the tablet space in May 2005 with the Nokia 770 running Maemo, a Debian-based Linux distribution custom-made for their Internet tablet line. The product line continued with the N900, with phone capabilities. The user interface and application framework layer, named Hildon, was an early instance of a software platform for generic computing in a tablet device intended for internet consumption. But Nokia didn't commit to it as their only platform for their future mobile devices and the project competed against other in-house platforms and later replaced it with the Series 60.

Following the launch of the Ultra-mobile PC, Intel started the Mobile Internet Device initiative, which took the same hardware and combined it with a tabletized Linux configuration. Intel co-developed the lightweight Moblin (mobile Linux) operating system following the successful launch of the Atom CPU series on netbooks.

MeeGo was a Linux-based operating system developed by Intel and Nokia that supports netbooks, smartphones and tablet PCs. In 2010, Nokia and Intel combined the Maemo and Moblin projects to form MeeGo. The first tablet using MeeGo is the Neofonie WeTab launched September 2010 in Germany. The WeTab uses an extended version of the MeeGo operating system called WeTab OS. WeTab OS adds runtimes for Android and Adobe AIR and provides a proprietary user interface optimized for the WeTab device. On September 27, 2011 the Linux Foundation announced that MeeGo would be replaced in 2012 by Tizen.

Application Store

As with smartphones, most mobile tablet apps are supplied through online distribution. These sources, known as "app stores", provide centralized catalogs of software and allow "one click" on-device software purchasing, installation and updates. The app store is often shared with smartphones that use the same operating system.

Mobile device suppliers typically adopt a "walled garden" approach, wherein the supplier controls what software applications ("apps") are available. Software development kits are restricted to approved software developers. This can be used to reduce the impact of malware, provide software with an approved content rating, control application quality and exclude competing vendors. Apple, Google, Amazon, Microsoft and Barnes & Noble all adopted the strategy. B&N originally allowed arbitrary apps to be installed, but, in December 2011, excluded third parties. Apple and IBM have agreed to cooperate in cross-selling IBM-developed applications for iPads and iPhones in enterprise-level accounts. Proponents of open source software say that it violates the spirit of personal control that traditional personal computers have always provided.

Sales

Around 2010, tablet use by businesses jumped, as business have started to use them for conferences, events, and trade shows. In 2012, Intel reported that their tablet program improved productivity for about 19,000 of their employees by an average of 57 minutes a day. In October 2012, display screen shipments for tablets began surpassing shipments for laptop display screens. Tablets are increasingly used in the construction industry to look at blueprints, field documentation and other relevant information on the device instead of carrying around large amounts of paper.

As of the beginning of 2014, 44% of US online consumers own tablets, a significant jump from 5% in 2011. Tablet use has also become increasingly common among children. A 2014 survey found that touch screens were the most frequently used object for play among American children under the age of 12. Touch screen devices were used more often in play than game consoles, board games, puzzles, play vehicles, blocks and dolls/action figures. Despite this, the majority of parents said that a touch screen device was "never" or only "sometimes" a toy. As of 2014, nearly two-thirds of American 2- to 10-year-olds have access to a tablet or e-reader. The large use of tablets by adults is as a personal internet-connected TV. A 2015 study found that a third of children under five have their own tablet device. While Android tablets sell more units than iPad, the web browser usage share of iPads is about 65% as of the middle of 2015.

By manufacturer

Note: Others consists of small vendors with mostly less market share.

By operating system

According to a survey conducted by the Online Publishers Association (OPA) now called Digital Content Next (DCN) in March 2012, it found that 72% of tablet owners had an iPad, while 32% had an Android tablet. By 2012, Android tablet adoption had increased. 52% of tablet owners owned an iPad, while 51% owned an Android-powered tablet (percentages do not add up to 100% because some tablet owners own more than one type). By end of 2013, Android's market share rose to 61.9%, followed by iOS at 36%. By late 2014, Android's market share rose to 72%, followed by iOS at 22.3% and Windows at 5.7%. As of early 2016, Android has 65% marketshare, Apple has 26% and Windows has 9% marketshare.

Sleep

The blue wavelength of light from back-lit tablets may impact one's ability to fall asleep when reading at night, through the suppression of melatonin. Experts at Harvard Medical School suggest limiting tablets for reading use in the evening. Those who have a delayed body clock, such as teenagers, which makes them prone to stay up late in the evening and sleep later in the morning, may be at particular risk for increases in sleep deficiencies. PC apps such as F.lux and Android apps such as CF.lumen and Twilight attempt to decrease the impact on sleep by filtering blue wavelengths from the display. iOS 9.3 has "Night Shift" built-in that shifts the colors of the device's display to be warmer.