Tablet computer

iPad (1st generation), a tablet computer
A tablet computer, or simply tablet, is a mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen and instead of using a physical keyboard it often uses an onscreen virtual keyboard. A tablet computer may be connected to a keyboard with a wireless link or a USB port. Convertible notebook computers have an integrated keyboard that can be hidden by a swivel joint or slide joint, exposing only the screen for touch operation. Hybrids have a detachable keyboard so that the touch screen can be used as a stand-alone tablet. Booklets include dual-touchscreens, and can be used as a notebook by displaying a virtual keyboard in one of them.
An early information tablet concept, named the Dynabook, was described by a Xerox scientist Alan C Kay, in his Aug 1972 paper: A Personal Computer for children of all Ages, the paper proposes a touch screen as a possible alternative means of input for the device. The first commercial portable electronic tablets appeared at the end of the 20th century. In 2010, Apple Inc. released the iPad which became the first mobile computer tablet to achieve worldwide commercial success. The iPad used technology similar to Apple's iPhone. Other manufacturers have produced tablets of their own including Samsung, HTC, Motorola, RIM, Sony, Amazon, HP, Microsoft, Google, Asus, Toshiba, and Archos. Tablets use a variety of operating systems such as iOS (Apple), Android (Google), Windows (Microsoft), and QNX (RIM).
As of March 2012[update], 31% of U.S. Internet users were reported to have a tablet, which was used mainly for viewing published content such as video and news. Among tablets available in the market in 2012, the top-selling device is Apple's iPad with 100 million sold by mid October 2012 since it was released in April 3, 2010, followed by Amazon's Kindle Fire with 7 million, and Barnes & Noble's Nook with 5 million. Contents * * 1 Background * 1.1 History * 1.2 Traditional tablet PCs * 1.3 "Post-PC" tablets * 2 Touch user interface * 2.1 Handwriting recognition * 2.2 Touchscreen hardware * 3 Typical functions * 4 Other features * 5 Form factors * 5.1 Slate * 5.2 Booklet * 5.3 Convertible * 5.4 Hybrid * 6 Mini tablet * 7 Phablet * 8 System architecture * 9 Operating systems and vendors * 9.1 Traditional Tablet PC operating systems * 9.1.1 Microsoft * 9.1.2 Linux * 9.1.3 Intel and Nokia * 9.1.3.1 MeeGo * 9.2 Post-PC operating systems * 9.2.1 iPad * 9.2.2 Blackberry * 9.2.3 Android * 9.2.4 HP * 9.2.5 One Laptop per Child organization * 10 Developing software for tablet computers * 11 Sales * |

Background

History

1888 telautograph patent schema
Main article: History of tablet computers
The tablet computer and the associated special operating software is an example of pen computing technology, and thus the development of tablets has deep historical roots.
Electrical devices with data input and output on a flat information display have existed as early as 1888 with the telautograph.[7] Throughout the 20th century many devices with these characteristics have been imagined and created whether as blueprints, prototypes, or commercial products. In addition to many academic and research systems, there were several companies with commercial products in the 1980s.
Tablet computers appeared in a number of works of Science Fiction in the second half of the 20th century, with the depiction of Arthur C. Clarke's NewsPad[8], in Stanley Kubrick's 1968 film 2001: A Space Odyssey, the description of Calculator Pad in the 1951 novel Foundation by Isaac Asimov, the Opton in the 1961 novel Return from the Stars by Stanislaw Lem, The Hitchhikers Guide to the Galaxy in Douglas Adams 1978 comedy of the same name, and not forgetting the numerous devices depicted in Gene Roddenberry 1966 Star Trek series, all helping to promote and disseminate the concept to a wider audience.[9]
Alan Kay attempted to formulate his Dynabook portable computer concept as early as 1968; with his 1972 paper: "A personal computer for children of all ages" detailing possible uses and functionality for his Dynabook concept.[10]
In 1994 the European Union initiated the 'OMI-NewsPAD' project (EP9252), requiring a consumer device be developed for the receipt and consumption of electronically delivered news / newspapers and associated multi-media. The NewsPad name and project goals were borrowed from and inspired by Arthur C. Clarke's 1965 screen play and Stanley Kubrick's 1968 film 2001: A Space Odyssey.[11] Acorn Computers developed and delivered an ARM based touch screen tablet computer for this program, branded the NewsPad. The device was supplied for the duration of the Barcelona based trial, which ended in 1997.
Intel announced a Strong ARM based touch screen tablet computer in 1999, under the name WebPAD, the tablet was later re-branded as the "Intel Web Tablet".[12]
During the 2000s, Microsoft attempted to define with the Microsoft Tablet PC the tablet personal computer product concept[13] as a mobile computer for field work in business,[14] though their devices failed to achieve widespread usage mainly due to price and usability problems that made them unsuitable outside of their limited intended purpose.[15]
In April 2010 Apple Inc. released the iPad, a tablet computer with an emphasis on media consumption. The shift in purpose, together with increased usability, battery life, simplicity, lower weight and cost, and overall quality with respect to previous tablets, was perceived as defining a new class of consumer device[16] and shaped the commercial market for tablets in the following year.[17]
As a result, two distinctly different types of tablet computing devices exist as of 2012, the Tablet PC and the Post-PC tablet, whose operating systems are of different origin.

Traditional tablet PCs
Main article: Early tablet computers
A tablet personal computer (tablet PC) is a portable personal computer equipped with a touchscreen as a primary input device, and running a modified desktop OS[18] designed to be operated and owned by an individual.[19] The term was made popular as a concept presented by Microsoft in 2000[20] and 2001[21] but tablet PCs now refer to any tablet-sized personal computer regardless of the (desktop) operating system.[22] Unlike modern tablet computers, traditional tablet PCs usually had a physical keyboard.
Tablet personal computers are mainly based on the x86 IBM-PC architecture[23] and are fully functional personal computers employing a slightly modified personal computer OS (such as Windows or Linux) supporting their touch-screen, instead of a traditional display, mouse and keyboard. A typical tablet personal computer needs to be stylus driven, because operating the typical desktop based OS requires a high precision to select GUI widgets, such as a close window button.

"Post-PC" tablets
See also: Mobile operating system
In 2005, an internet tablet, the Nokia 770, was introduced. This product line used the Maemo Linux operating system. Mobile operating systems have a different kind of interface than the traditional desktop OS, and represent a new type of computing device.[24] These "post-PC" mobile OS tablet computer devices are normally finger driven and most frequently use capacitive touch screens with multi-touch, unlike earlier stylus-driven resistive touchscreen devices.
The most successful tablet computer is the Apple iPad using the iOS operating system. Its debut in 2010 popularized tablets into mainstream.[25][26] Samsung's Galaxy Tab and others followed, continuing the now common trends towards multi-touch and other natural user interface features, as well as flash memory solid-state storage drives and "instant on" warm-boot times; in addition, standard external USB and Bluetooth keyboards can often be used. Most frequently the operating system running on a tablet computer (one not based on the traditional Windows/x86 PC architecture) is a Unix-like OS, such as Darwin, Linux or QNX. Some have 3G mobile telephony capabilities.[27]
In forgoing the x86 precondition (a requisite of Windows compatibility), most tablet computers released since mid-2010 use a version of an ARM architecture processor for longer battery life versus battery weight, heretofore used in portable equipment such as MP3 players and smartphones. Especially with the introduction of the ARM Cortex family, this architecture is now powerful enough for tasks such as internet browsing, light production work and mobile games.[28]
A significant trait of tablet computers not based on the traditional PC architecture is that most mobile apps including third party ones are supplied through online distribution, rather than more traditional methods of boxed software or direct sales from software vendors. These sources, known as "app stores", provide centralized catalogues of software from the OS supplier or device manufacturer and from outside parties, and allow simple "one click" on-device software purchasing, installation, and updates.

Touch user interface

Samsung Galaxy Tab demonstrating multi-touch
A key and common component among tablet computers is touch input. This allows the user to navigate easily and intuitively and type with a virtual keyboard on the screen. 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.[29]
The event processing of the operating system must respond to touches rather than clicks of a keyboard or mouse, which allows integrated hand-eye operation, a natural part of the somatosensory system. Although the device implementation differs from more traditional PCs or laptops, tablets are disrupting the current vendor sales by weakening traditional laptop PC sales in favor of the current tablet computers. This is even more true of the "finger driven multi-touch" interface of the more recent tablet computers, which often emulate the way actual objects behave.

Handwriting recognition

Chinese characters like this one meaning "person" can be written by handwriting recognition (, Mandarin: rén, Korean: in, Japanese: jin, nin; hito, Cantonese: jan4). The character has two strokes, the first shown here in dark, and the second in red. The black area represents the starting position of the writing instrument.
Some tablet personal computers use a stylus. These tablets often implement handwriting recognition. Tablet computers with finger driven screens usually do not. Finger driven screens are potentially better suited for inputting "variable width stroke based" characters, like Chinese/Japanese/Korean writing, due to their built in capability of "pressure sensing". However at the moment not much of this potential is already used, except in digital art applications like Autodesk Sketchbook for the iPad, and as a result even on tablet computers Chinese users often use a (virtual) keyboard for input.[33]

Touchscreen hardware
Touchscreens are usually one of two forms; * Resistive touchscreens are passive and can respond to any kind of pressure on the screen. They allow a high level of precision, useful in emulating a pointer as is common in tablet computers) but may require calibration to be accurate. Because of the high resolution of detection, a stylus or fingernail is often used for resistive screens. Limited possibilities exist for implementing multi-touch on a resistive touch-screen. As modern tablet computers tend to heavy use of multi-touch, this technology has faded out on high-end devices where it has been replaced by capacitive touchscreens. * Capacitive touchscreens tend to be less accurate, but more responsive than resistive screens. Because they require a conductive material, such as a finger tip, for input, they are not common among (stylus using) Tablet PCs but are more prominent on the smaller scale "tablet computer" devices for ease of use, which generally do not use a stylus, and need multi-touch capabilities.
Other touch technology used in tablets include: * Palm recognition. It prevents inadvertent palms or other contacts from disrupting the pen's input. * Multi-touch capabilities, which can recognize multiple simultaneous finger touches, allowing for enhanced manipulation of on-screen objects.[34]
Some professional-grade Tablet PCs use pressure sensitive films that additionally allow pressure sensitivity such as those on graphics tablets.
Concurrently capacitive touch-screens, which use finger tip detection can often detect the size of the touched area, and can make some conclusions to the pressure force used, for a similar result.[35]

Typical functions
Typical functions of tablet computers in 2012 are: * Wireless mobile browser functions (using 2G, 3G, 4G or WiFi) * E-mail and social media devices (typically with integration apps to bring all feeds into the same view) * Potential cell phone functions (Messaging, video calling, speakerphone or headset cellphone uses) * GPS satellite navigation * Stills and video camera functions, photo and video viewing and editing * E-book reading (including electronic versions of periodicals) * Downloadable apps (games, education, utilities) * Portable media player function * Weigh around one or two pounds (0.5 - 1 kilogram) * Battery life of three to twelve hours depending on usage pattern.

Other features * Accelerometer: A device that detects the physical movements of the tablet. This allows greater flexibility of use since tablets do not necessarily have a fixed direction of use. The accelerometer can detect the orientation of the tablet relative to the horizontal plane, and movement of the tablet, both of which can be used as an alternative control interface for a tablet's software. * Ambient light and proximity sensors are additional "senses", that can provide controlling input for the tablet. * Storage drive: Large tablets use storage drives similar to laptops, while smaller ones tend to use drives similar to MP3 players or have on-board flash memory. They also often have ports for removable storage such as Secure Digital cards. Due to the nature of the use of tablets, solid-state memory is often preferable due to its better resistance to damage during movement. * Wireless: Because tablets by design are mobile computers, wireless connections are less restrictive to motion than wired connections. Wi-Fi connectivity has become ubiquitous among tablets. Bluetooth is commonly used for connecting peripherals and communicating with local devices in place of a wired USB connection. * 3D: Following mobile phone, there are also 3D slate tablet with dual lens at the back of the tablet and also provided with blue-red glasses.[36] * Docking station: Some newer tablets are offering an optional docking station that has a full size qwerty keyboard and USB port, providing both portability and flexibility.

Form factors
Tablet computers come in a range of sizes, currently ranging from tablet PCs to PDAs. Traditional tablet personal computers tend to be as large as laptops and often are the largest usable size for mobile tablet computing while the new generation of tablet computers can be much smaller and use a RISC (ARM or MIPS) CPU, and in size can border on PDAs.

Slate

Writing slate with sponge (~1950). The slate format is named with a metaphor of this low-tech writing device.
Slate computers, which resemble writing slates, are tablet computers without a dedicated keyboard. For text input, users rely on handwriting recognition via an active digitizer, touching an on-screen keyboard using fingertips or a stylus, or using an external keyboard that can usually be attached via a wireless or USB connection.
Slate computers typically incorporate small (8.4–14.1 inches/21–36 centimetres) LCD screens and have been popular in vertical markets such as health care, education, hospitality, aviation (pilot documentation and maps),[37] and field work. Applications for field work often require a tablet computer that has rugged specifications that ensure long life by resisting heat, humidity, and drop/vibration damage. This added focus on mobility and/or ruggedness often leads to elimination of moving parts that could hinder these qualities.

Booklet
Booklet computers are dual-touchscreen tablet computers that fold like a book. Typical booklet computers are equipped with multi-touch screens and pen writing recognition capabilities. They are designed to be used as digital day planners, Internet surfing devices, project planners, music players, and displays for video, live TV, and e-reading.

Convertible

A Lenovo X61 in slate mode
Convertible notebooks have a base body with an attached keyboard. They more closely resemble modern laptops, and are usually heavier and larger than slates.
Typically, the base of a convertible attaches to the display at a single joint called a swivel hinge or rotating hinge. The joint allows the screen to rotate through 180° and fold down on top of the keyboard to provide a flat writing surface. This design, although the most common, creates a physical point of weakness on the notebook.
Some manufacturers have attempted to overcome these weak points. The Panasonic Toughbook 19, for example, is advertised as a more durable convertible notebook. (Panasonic also offers the Toughpad, a water- and shockproof Android tablet.) Meanwhile, the HP EliteBook 2760p convertible notebook uses a reinforced hinge that protrudes slightly from the rear of the unit. And, one model by Acer, the TravelMate C210, has a sliding design in which the screen slides up from the slate-like position and locks into place to provide the laptop mode.
Sliding screens were presented at CES 2011. The first product to use it is the Samsung Sliding PC7 Series,[38] a tablet with Intel Atom hardware and a unique sliding screen that allows the product to be used as a laptop or slate tablet when the screen is locked in place covering the whole keyboard. The concept must still prove its reliability, but is intended to combine the virtues of tablet PCs with those of notebooks. Also presented was the upcoming Inspiron Duo from Dell, which rotates the screen horizontally when opened. Convertibles like that with hardware specs of a netbook are called netvertibles.

Hybrid
Hybrids, a term coined by users of the HP/Compaq TC1000 and TC1100 series, share the features of the slate and convertible by using a detachable keyboard that operates in a similar fashion to a convertible when attached. Hybrids are not to be confused with slate models with detachable keyboards; detachable keyboards for pure slate models do not rotate to allow the tablet to rest on it like a convertible.

Mini tablet

Nexus 7, a 7 inch tablet computer
Mini tablets are smaller and lighter than full-sized tablets. The first successful ones were introduced by Samsung (Galaxy Tab 7-inch), Barnes and Noble (the Nook), Blackberry Playbook, and Amazon (the Kindle Fire) in 2011, and by Google (the Nexus 7) in 2012. Most of them work like a regular tablet, though some of them may not have all the features and functions found in bigger tablet computers. The typical mini tablet is generally 6 or 7 inches (15 - 17.6 cm) diagonal. Mini tablets, such as the Toshiba Regza 6-inch tablet and the Sylvania 7-inch, are easier to transport in pockets and purses than the larger 9+ inch types, such as the iPad.[39][40]
Apple has released their own smaller version of the iPad tablet, called the iPad Mini. Its size is 7.9 inches, almost 2 inches smaller than the regular size iPad tablet, which is at 9.7 inches. This is thought to compete with other mini-tablets, such as the Nexus 7 and Kindle Fire. Apple announced the new smaller-sized tablet on October 23, 2012.[41]

Phablet
Since 2010, crossover touch-screen devices with screens of 5-inches and above have been released. That size is generally considered too large for a touch-screen smartphone and too small for a tablet, creating a hybrid category different from the previous common classifications. This hybrid is being called a phablet by Forbes and Engadget. Phablet is a portmanteau of the words phone and tablet.[42] Popular examples of phablets are the LG Optimus Vu, Samsung Galaxy Note and Dell Streak. The rival term 'PhoneTab' has not caught on. Samsung claims they had shipped a million units of the Galaxy Note within two months of introducing it.[43][44]

System architecture
See also: Comparison of tablet computers
Two major computer architectures dominate the tablet market,[45] Intel's x86 and ARM architecture.
Intel's x86, including x86-64 has provided the brains of the IBM compatible PC since 1981, and Apple's Mac computers since 2006. The CPU's have been incorporated into a number of tablet PCs over the years and have generally offered greater performance along with the ability to run a full versions of Microsoft Windows, along with the associated 25 years of associated Windows desktop and enterprise applications on the devices. There are also non-Windows based x86 tablets like the JooJoo.
ARM has been the CPU architecture of choice for: mobile phone, pda, camera, set-top box, dsl routers, television, storage device and tablet computer manufacturers this century. This dominance dates back to the release of the mobile focused and comparatively power / battery efficient 32 bit ARM610 SoC (System On a Chip) originally designed for the Apple Newton and Acorn A4 back in 1993. The chip was rapidly adopted by the likes of Psion, Palm and Nokia for their own PDA offerings and later smart phones, camera phones, cameras, etc..... ARM's licensing model has also helped in this spread and current dominance of the mobile device space; by allowing device manufacturers to: licence, alter and fabricate custom SoC derivatives, specifically tailored to their own products. This has helped manufacturers extend battery life and shrink the component count along with the devices size. The multiple licensee have also ensured multiple generic ARM fabricators are supplying near identical products into the market, while encouraging price competition.This has historically forced unit prices down to a fraction of their x86 equivalents, as well as offering the manufacture some insurance against supply insecurities. The architecture has historically had limited support from Microsoft, with only Windows CE available, but with the release of Windows 8, in 2012, Microsoft has announced greater support for the architecture, as well as shipping their own range of ARM based tablet computers, branded as the Microsoft Surface, though a later x86 Atom based PRO variant of the Surface will be delivered[46][47][48][49]

Operating systems and vendors
Tablets, like regular computers, can run a number of operating systems. These come in two classes, namely traditional desktop-based operating systems and post-PC mobile-based ("phone-like") operating systems.
For the former class popular OS's are Microsoft Windows, and a range of Linux distributions. HP is developing enterprise-level tablets under Windows and consumer-oriented tablets under webOS. In the latter class the popular variants include Apple iOS, and Google Android. Manufacturers are also testing the market for products with Windows CE, Chrome OS,[50][51] and so forth.

Traditional Tablet PC operating systems

Microsoft
Main article: Microsoft Tablet PC
Following Windows for Pen Computing, Microsoft has been developing support for tablets running Windows under the Microsoft Tablet PC name.[52] According to a 2001 Microsoft definition[53] of the term, "Microsoft Tablet PCs" are pen-based, fully functional x86 PCs with handwriting and voice recognition functionality. Tablet PCs use the same hardware as normal laptops but add support for pen input. For specialized support for pen input, Microsoft released Windows XP Tablet PC Edition. Today there is no tablet specific version of Windows but instead support is built in to both Home and Business versions of Windows Vista and Windows 7. Tablets running Windows get the added functionality of using the touchscreen for mouse input, hand writing recognition, and gesture support. Following Tablet PC, Microsoft announced the UMPC initiative in 2006 which brought Windows tablets to a smaller, touch-centric form factor. This was relaunched in 2010 as Slate PC, to promote tablets running Windows 7, ahead of Apple's iPad launch.[54][55] Slate PCs are expected to benefit from mobile hardware advances derived from the success of the netbooks.
While many tablet manufacterurs are moving to the ARM architecture with lighter operating systems, Microsoft has stood firm to Windows.[56][57][58][59] Microsoft has announced Windows 8 which will have the new Metro user interface suited to touchscreen devices such as tablets. .[60]
For the first time, Windows will be able to run the ARM architecture because of Windows RT which can run on processors from NVIDIA, Qualcomm and Texas Instruments[61][62] Microsoft has also launched their own tablet called the Microsoft Surface.
Prior to Windows 8 and Windows Phone 8, Windows CE was used to target smart phones in the form of Windows Phone 7. Windows Phone 8 uses the same code as Windows 8. Also, some manufacturers, however, still have shown prototypes of Windows CE-based tablets running a custom shell.[63]

Linux
One early implementation of a Linux tablet was the ProGear by FrontPath. The ProGear used a Transmeta chip and a resistive digitizer. The ProGear initially came with a version of Slackware Linux, but could later be bought with Windows 98. Because these computers are general purpose IBM PC compatible machines, they can run many different operating systems. However, the device is no longer for sale and FrontPath has ceased operations. It is important to note that many touch screen sub-notebook computers can run any of several Linux distributions with little customization.
X.org now supports screen rotation and tablet input through Wacom drivers, and handwriting recognition software from both the Qt-based Qtopia and GTK+-based Internet Tablet OS provide promising free and open source systems for future development. KDE's Plasma Active is graphical environments for tablet.[64]
Open source note taking software in Linux includes applications such as Xournal (which supports PDF file annotation), Gournal (a Gnome based note taking application), and the Java-based Jarnal (which supports handwriting recognition as a built-in function). Before the advent of the aforementioned software, many users had to rely on on-screen keyboards and alternative text input methods like Dasher. There is a stand alone handwriting recognition program available, CellWriter, which requires users to write letters separately in a grid.
A number of Linux based OS projects are dedicated to tablet PCs, but many desktop distributions now have tablet-friendly interfaces allowing the full set of desktop features on the smaller devices. Since all these are open source, they are freely available and can be run or ported to devices that conform to the tablet PC design. Maemo (rebranded MeeGo in 2010), a Debian Linux based graphical user environment, was developed for the Nokia Internet Tablet devices (770, N800, N810 & N900). It is currently in generation 5, and has a vast array of applications available in both official and user supported repositories. Ubuntu since version 11.04 has used the tablet-friendly Unity UI, and many other distributions (such as Fedora) use the also tablet-friendly Gnome shell (which can also be installed in Ubuntu if preferred). Previously the Ubuntu Netbook Remix edition was one of the only linux distibutions offering a tablet interface with all the applications and features of a desktop distribution, but this has been phased out with the expansion of Unity to the desktop. A large number of distributions now have touchscreen support of some kind, even if their interfaces are not well suited to touch operation.
Canonical has hinted that Ubuntu will be available on tablets, as well as phones and smart televisions, by 2014.[65]
TabletKiosk currently offers a hybrid digitizer / touch device running openSUSE Linux. It is the first device with this feature to support Linux.

Intel and Nokia

The Nokia N800
Nokia entered the tablet space 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 which is the first to add 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.[66] 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. The strategic advantage of a modern platform was not exploited, being displaced by the Series 60. [67]
Intel, following the launch of the UMPC, started the Mobile Internet Device initiative, which took the same hardware and combined it with a Linux operating system custom-built for portable tablets. Intel co-developed the lightweight Moblin operating system following the successful launch of the Atom CPU series on netbooks. Intel is also setting tablet goals for Atom, going forward from 2010.[68][69]

MeeGo
Main articles: Maemo, MeeGo, and Tizen
MeeGo is 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 27 September 2011 it was announced by the Linux Foundation that MeeGo will be replaced in 2012 by Tizen, an open source mobile operating system.[70]

Post-PC operating systems
See also: Mobile operating system
Tablets not following the personal computer (PC) tradition use operating systems in the style of those developed for PDAs and smartphones.

iPad
Main articles: iOS (Apple), iPad, and ModBook

The iPad in a case
The iPad runs a version of iOS which was first created for the iPhone and iPod Touch. Although built on the same underlying Unix implementation as MacOS, the operating system differs radically at the graphical user interface level. iOS is designed for finger based use and has none of the tiny features which required a stylus on earlier tablets. Apple introduced responsive multi touch gestures, like moving two fingers apart to zoom in. iOS is built for the ARM architecture, which uses less power, and so gives better battery life than the Intel devices used by Windows tablets. Previous to the iPad's launch, there were long standing rumors of an Apple tablet, though they were often about a product running Mac OS X and being in line with Apple's Macintosh computers.[71] This became partially true when a 3rd party offered customized Macbooks with pen input, known as the Modbook.
Previous to Apple's commercialization of the iPad, Axiotron introduced at Macworld in 2007[72] an aftermarket, heavily modified Apple MacBook called Modbook, a Mac OS X-based tablet personal 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 is supplied with a third-party driver called TabletMagic; Wacom does not provide driver support for this device.

Blackberry
The BlackBerry PlayBook is a tablet computer announced in September 2010 which runs the BlackBerry Tablet OS.[73] The OS is based on the QNX system that Research in Motion acquired in early 2010. Delivery to developers and enterprise customers was expected in October 2010. The BlackBerry PlayBook was officially released to US and Canadian consumers on April 19, 2011.

Android
Main articles: Android (operating system) and Google Chrome OS

An ASUS Eee Pad Transformer running Android 3.2.1 Honeycomb; the keyboard is part of a docking station for the tablet.
Google's Linux-based Android operating system is used by tablet manufacturers following its success on smartphones due to its support for low-cost ARM systems much like Apple's iOS. Many were announced in 2010.[74] However, much of Android's tablet initiative came from manufacturers as long as Google primarily focused on smartphones and restricted the App Market from non-phone devices.[75]
There is perennial talk of tablet support from Google coming to its web-centric Chrome OS.[76][77]
Some vendors such as Motorola[78] and Lenovo[79] delayed deployment of their tablets until after 2011, when Android was reworked to include more tablet features.[80] Android 3.0 (Honeycomb) and later versions are optimized specifically for larger screen sizes, mainly tablets, and have access to the Google Play service. Android is the software stack for mobile devices that includes operating system, middleware and key applications.
Other vendors sell customized tablets such as Nook and Kindle Fire which are used for mobile content from their own Website, and seldom from the larger Google Play system. This has led to market fragmentation.[81]

HP
Hewlett Packard announced the TouchPad, running webOS 3.0 on a 1.2 GHz Snapdragon CPU, would be released in June 2011. On August 18, 2011, HP announced the discontinuation of the TouchPad, due to sluggish sales.[82] HP has announced that they will release webOS as open-source.[83]
[edit] One Laptop per Child organization

OLPC XO-3 tablet computer[84]
The One Laptop per Child (OLPC) organization is developing a new version of the OLPC, strongly resembling a tablet computer, called the OLPC XO-3, running its "Sugar" operating system, based on Linux. The new XO-3 will be based on ARM technology from Marvell.[85]
India
OLPC plans to introduce a tablet computer to India for $100.[86] Nicholas Negroponte, Chairman of OLPC, has invited the Indian researchers to MIT to begin sharing the OLPC design resources for their tablet computers.[87] OLPC has been awarded a grant for an interim step to their next-generation tablet, OLPC XO-3.[88]

Developing software for tablet computers
See also: Mobile development
The new class of devices heralded by the iPad has spurred the tendency of a walled garden approach, wherein the vendor reserves rights as to what can be installed. The software development kits for these platforms are restricted and the vendor must approve the final application for distribution to users. These restrictions allow the hardware vendor to control the kind of software that can be used and the content that can be seen in the devices; this can be used to reduce the impact of malware on the platform and to provide material of approved content rating, and also to exclude software and content from competing vendors. The walled garden approach to application development has proven to be a competitive advantage for the iPad over HP's TouchPad, triggering HP's withdrawal from the industry, due in large part to sluggish TouchPad sales after only 49 days on the market.[89]
Barnes and Noble adopted the walled garden strategy with its Nook Color and Nook Tablet e-book reader tablets, which FastCompany writer Austin Carr refers to as "an odd idea of progress", since B&N lacks the competitive advantages of number of apps and price enjoyed by Apple and Amazon.com. B&N's strategy became especially notable following pronouncements by B&N executives criticizing Amazon.com's walled garden approach, which they contrasted with B&N's emphasis on user choice. Specifically, in a mid-December interview, B&N CEO William Lynch called Amazon's Kindle Fire a "deficient" media tablet designed as a "vending machine for Amazon's services", and a device aimed to "lock consumers into [Amazon's] ecosystem". In contrast, B&N's Nook Tablet gave users choice and a much more "open" experience which, according to Lynch, may be one of the Nook Tablet's most significant selling points. In the same interview, B&N's director of developer relations Claudia Romanini reiterated, "It's about giving [consumer] choice and range. What we mean in terms of choice, is that we don't lock a customer into a service and say, 'This is the way you're going to get your media.'".[90] Indeed, Nook Tablets shipped until December 2011 were lauded by reviewers and users for permitting users to download and sideload third-party apps,[91][92] but, one week before Christmas, B&N began pushing an automatic, over-the-air firmware update 1.4.1 to Nook Tablets that removed users' ability to gain root access to the device and the ability to sideload apps from sources other than the official Barnes and Noble app store (without modding).[93][94][95][96][97]
Proponents of open source software deem that these restrictions on software installation and lack of administrator rights make this category one that, in their view, cannot be properly named "personal computers".[98][99][100] Some newer tablet computers using mobile operating systems don't use the walled garden concept, and are like personal computers in this regard.[citation needed]

Sales

Among tablets available in the market, Apple's iPad (left) is the top-selling tablet with 100 million units sold by mid October 2012, followed by Amazon's Kindle Fire (right) with 7 million.
According to a survey conducted by the Online Publishers Association (OPA) in March 2012, 31% percent of Internet users in the United States own a tablet, up from 12% in 2011. The OPA estimates that tablet ownership among the U.S. Internet population will rise to 47%. The survey also found that 72% of tablet owners had an iPad, while 32% had an Android tablet in 2011; and by 2012, Android tablet adoption has increased, with 52% of tablet owners using an iPad, while 51% use an Android-powered tablet. The percentages do not add up to 100% because some tablet owners own/use more than one type of tablet.[4]
As of October 2012[update], the top-selling tablet is Apple's iPad with 100 million units sold,[5] and according to estimates by Forrester Research, the iPad family is followed by Amazon's Kindle Fire with 7 million, Barnes and Noble's Nook 5 million, and Google's Nexus 7 with 3 million units.[6]