Hardware

Screen and input

The original iPad in its black case.For the iPad 2, Apple sells a Smart Cover rather than a case.

The iPad's (first two generations) touchscreen display is a 1,024 by 768 pixel, 7.75×5.82 in (197×148 mm) liquid-crystal display (diagonal 9.7 in (246.4 mm)), with fingerprint- and scratch-resistant glass. Steve Jobs said a 7-inch screen would be "too small to express the software" and that 10 inches was the minimum for a tablet screen.^[55] Like the iPhone, the iPad is designed to be controlled by bare fingers; normal, non-conductive gloves andstyli do not work,^[56] although there are special gloves and capacitive styli designed for this use.^[57][58]

The display responds to other sensors: an ambient light sensor to adjust screen brightness and a 3-axis accelerometer to sense iPad orientation and switch between portrait and landscape modes. Unlike the iPhone and iPod Touch's built-in applications, which work in three orientations (portrait, landscape-left and landscape-right), the iPad's built-in applications support screen rotation in all four orientations, including upside-down. Consequently, the device has no intrinsic "native" orientation; only the relative position of the home button changes.^[59]

There are four physical switches on the iPad, including a home button near the display that returns the user to the main menu, and three plastic physical switches on the sides: wake/sleep and volume up/down, plus a software-controlled switch whose function has changed with software updates. Originally the switch locked the screen to its current orientation, but the iOS 4.2 changed it to a mute switch, with rotation lock now available in an onscreen menu.^[60] In the iOS 4.3 update, released with the iPad 2, a setting was added to allow the user to specify whether the side switch was used for rotation lock or mute.^[6]

The first generation iPad had no camera; the iPad 2 has a front VGA camera and a rear-facing 720p camera, both capable of still images (but these are only taken at a low quality 0.3 megapixels) and 30fps video. The rear-facing camera has a 5× digital zoom for still images only. Both shoot photo and video in a 4:3 fullscreen aspect ratio, unlike the iPhone 4, which shoots in a 16:9 widescreen aspect ratio. Unlike the iPhone, the iPad does not support tap to focus, but does allow a tap to set auto exposure.^[61] The cameras allow FaceTime video messaging with iPhone 4, fourth generation iPod Touch, and Snow Leopard, Lion, and Mountain LionMacs.^[62]

Ipad

iPad (/ˈaɪpæd/ eye-pad) is a line of tablet computers designed and marketed by Apple Inc., which runs Apple's iOS. The first iPad was released on April 3, 2010; the most recent iPad models, the iPad Air and second generation iPad Mini, were revealed on October 22, 2013 and went on sale November 1, 2013, and November 12, 2013, respectively. The user interface is built around the device's multi-touch screen, including a virtual keyboard. The iPad has built-in Wi-Fi and, on some models, cellular connectivity. There have been over 170 million iPads sold since its release in 2010 (as of October 2013).^[5]

An iPad can shoot video, take photos, play music, and perform Internet functions such as web-browsing and emailing. Other functions—games, reference, GPS navigation, social networking, etc.—can be enabled by downloading and installing apps. As of October 2013, the App Store has more than 475,000 native apps by Apple and third parties.^[14]

There have been five versions of the iPad. The first generation established design precedents, such as the 9.7-inch screen size and button placement, that have persisted through all models. The iPad 2 added a dual coreApple A5 processor and VGA front-facing and 720p rear-facing cameras designed for FaceTime video calling. The third generation added a Retina Display, the new Apple A5X processor with a quad-core graphics processor, a 5-megapixel camera, HD 1080p video recording, voice dictation, and 4G (LTE). The fourth generation added the Apple A6X processor and replaces the 30-pin connector with an all-digital Lightning connector. The iPad Air added the Apple A7 processor, the Apple M7 motion coprocessor and reduced the form factor for the first time since the iPad 2. iOS 5.1 added Siri to the third and fourth generations and the iPad Mini.

There have been two versions of the iPad Mini. The first generation features a reduced screen size of 7.9 inches and features similar internal specifications as the iPad 2. It also uses the Lightning connector. The second generation features the Retina Display, the Apple A7 processor and the Apple M7 motion coprocessor, matching the internals specifications of the iPad Air.