iPad
The iPad is a tablet PC from Apple. The first iPads were introduced at the beginning of 2010. After the Newton, the iPad is the second mobile computer( PDA) without keyboard from Apple. The iPad is suitable for playing music, videos, photos and e-books. The built-in web browserSafari allows access to the Internet via WLAN or UMTS with High Speed Downlink Packet Access( HSDPA) and GSM with EDGE. The iPad uses a 1 GHz Apple A4 ARM processor with SOC design from P.A. Semi, formerly "Palo Alto Semiconductor", a Santa Clara-based semiconductor manufacturer acquired by Apple in 2008.
Touchscreen of the iPad
The iPad is controlled via a touch-sensitive multi-touch screen. The display has a diagonal of 9.7 inches (24.63 cm) and backlight with LED array, glossy display and IPS technology, in-plane switching(IPS). The resolution of the first models of iPad was 1024 x 768 pixels at 132 ppi. Successor devices like the iPad 3, which use Retina display, have four times the resolution of 2,048 x 1,536 pixels, which is equivalent to 3.146 million pixels. The IPS display responds to the user's finger pressure gestures (multi-touch), and its brightness is adjusted via an ambient light sensor. An acceleration sensor allows controlling applications as well as switching between vertical or horizontal display of the screen content.
The user can activate different functions with multitouch gestures, e.g. a spreading motion with two fingers enlarges an image file. As with the iPhone, the iPad's capacitive touchscreen does not allow input with a stylus. In many apps, a keyboard can be displayed at the bottom of the screen for entering characters, and an external keyboard can optionally be connected via Bluetooth.
Apps from the App Store
Most of the software apps offered in Apple's App Store can also be used with the iPad, sometimes with a loss of quality in the visual display if they were originally developed for the iPhone or iPod Touch. Apple offers an iPad version of the office suite iWork, which can be used with Multitouch. With Apple's iBooks, e-books can be read in EPUB format and PDF format and purchased from Apple's iBook store.
Apps are written with the Xcode development environment, which also includes a simulator for the iPhone and iPad. Adobe Flash was not implemented in the development of the iPad. As a result, websites with Flash content cannot be played on the iPad.
Features and interfaces
The iPad has a stereo headphone jack (3.5 mm), integrated speakers, a microphone and a 30- pin connector for docking stations. An adapter allows the connection of a USB interface or the VGA interface and SD cards.A rechargeable lithium polymer battery with a capacity of 25 watt hours(Wh) is permanently installed and offers a runtime of up to 10 hours for WLAN surfing or playing video or music, according to the manufacturer. The battery life is stated at 5 years.
The iPad can be operated on computers with USB 2.0 port and iTunes, including the Apple Macintosh or a personal computer with Windows 7, Vista, XP Home or Professional with Service Pack 3. The Micro-USB interface has been replaced by the Lightning interface. The iPad provides only one user account, so multiple users have to share the email client, calendar or personal settings.