Your smartphone isn't really mobile; you are
Strictly speaking, a smartphone is not a mobile device at all. It goes nowhere on its own; the person carrying it does the moving. Truly mobile computers move themselves, like robots or self-driving cars. The distinction sounds pedantic, but it shapes how engineers think about the handheld gadgets that now dominate computing.
A mobile device is a computer small enough to hold and use in the hand, usually battery-powered, with a flat screen and a touchscreen or keypad. Such devices can be tied to their carriers in different ways: embedded in a host, as a controller is built into a car, or merely accompanying it, like a phone in a pocket that is easy to lose. Mobility and wireless connectivity are also different things. Many phone functions work offline, and a wireless access point can sit perfectly still.
The computing pioneer Mark Weiser, often called the father of ubiquitous computing, sorted devices by scale: centimetre-sized tabs such as phones, decimetre-sized pads such as tablets, and larger boards. Beyond these lie 'dust', microscopic machines with no direct interface, and 'skin', flexible displays woven from light-emitting polymers into clothes or curtains. The most common smart device may not even have a screen: bank and travel smart cards carry a processor and memory but reveal their contents only through a reader.
Early handhelds each did one job well, whether calculators, music players, satellite navigators or digital cameras. Personal digital assistants spread in the 1990s for notes, appointments and reminders. Meanwhile phones grew from voice-only to texting, internet access, multimedia and video calls, and smartphones eventually swallowed all these gadgets. They have been the world's best-selling mobile devices since the late 2000s.
By the early 2010s phones carried accelerometers, magnetometers and gyroscopes to sense motion and orientation, and many now unlock with a face or fingerprint. Rugged enterprise handhelds scan barcodes and RFID tags in the field. Watching television on the move is older than most assume: portable TV receivers have existed since 1960.
Source: Mobile device
