Mobile computing refers to computing on handheld smartphones and tablet computers. These devices share the distinguishing physical features of being portable and lightweight. Historically, compared with desktop and laptop computers, mobile systems gave up screen size, memory capacity, and overall functionality in return for handheld mobile access to services such as e-mail and web browsing. Over the past few years, however, features on mobile devices have become so rich that the distinction in functionllity between, say, a comsumer laptop and tablet computer amy be difficult to discern, In fact we might argue that the features of a contemporary mobile device allow it toprovide functionality that is either unavailable or impractical on a desktop or laptop computer.
Today, mobile systems are used not only for e-mail and web browsing but also for playing music and video, reading digital books, taking photos, and recording and editing high-definition video. Accordingly, tremendous growth continues in the wide range of applications that run on such devices. Many developers are now designing applications that take advantage of the unique features of mobile devices, such as global prositioning system (GPS) chips, accelerometers, and gyroscopes. An embedded GPS chip allows a mobile device to use satelites to determine its precise on Earth. That functionality is especially useful in designing applications that provide navigation-for example, telling users which way to walk or drive or perhaps directing them to nearby services, such as restaurants. An accelerometer allows a mobile device to detect its orientation with respect to the ground and to detecct certain other forces, such as titling and shaking. In serveral computer games that employ accelerometers, players interface with the system not by using a mouse or a keyboard but rather by tilting and shaking. In serveral computer games that employ accelerometers, players interface with the system not by using a mouse or a keyboard but rather by tilting and shaking. In several computer games that employ accelerometers, players interface with the system not by using a mouse or a keyboard but rather by titing, roating, and shaking the mobile device! Perhaps more a practial use of these features is found in augmented-reality applications, which overlay information on a display of the current environment. It it difficult to imagine how equivalent applications could be developed on traditional laptop or desktop computer systems.
To provide access to on-line services, mobile devices typically use either IEEE standard 802.11 wireless or cellular data networks. The memory capacity and processing speed of mobile devices, however, are more limited than those of PCs. Whereas a smarphone or tablet may have 256GB in storage, it isi not uncommon to find 8 TB in storage on a desktop computer, Similarly, because power consumption is such a concern, mobile devices often use processors that are smaller, are slower, and offer fewer processing core than processors found on traditional desktop and laptop computers.
Two operating systems currently dominate mobile computering: Apple iOS and Google Android. iOS was designed to run on Apple iPhone and iPad mobile devices, Android powers smartphones and tablet computers available from many manufacturers. We examine these two mobile operating system in further detail in Chapter 2.
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