Characteristics

Device mobility can be viewed in the context of several qualities:

• Physical dimensions and weight
• Whether the device is mobile or some kind of host to which it is attached is mobile
• To what kind of host devices can it be bound
• How devices communicate with a host
• When the mobility occurs

Strictly speaking, many so-called mobile devices are not mobile. It is the host that is mobile, i.e., a mobile human host carries a non-mobile smartphone device. An example of a true mobile computing device, where the device itself is mobile, is a robot. Another example is an autonomous vehicle. There are three basic ways mobile devices can be physically bound to mobile hosts: accompanied, surface-mounted or embedded into the fabric of a host, e.g., an embedded controller embedded in a host device. Accompanied refers to an object being loosely bound and accompanying a mobile host, e.g., a smartphone can be carried in a bag or pocket but can easily be misplaced. Hence, mobile hosts with embedded devices such as an autonomous vehicle can appear larger than pocket-sized.

As stated earlier, the most common size of mobile computing device is pocket-sized that can be hand-held, but other sizes for mobile devices exist, too. Mark Weiser, knownby whom? as the father of ubiquitous computing, computing everywhere, referred to device sizes that are tab-sized, pad and board sized, where tabs are defined as accompanied or wearable centimetre-sized devices, e.g. smartphones, phablets and pads are defined as hand-held decimetre-sized devices. If one changes the form of the mobile devices in terms of being non-planar, one can also have skin devices and tiny dust-sized devices. Dust refers to miniaturised devices without direct HCI interfaces, e.g., micro electro-mechanical systems (MEMS), ranging from nanometres through micrometers to millimetres. See also Smart dust. Skin: fabrics based upon light emitting and conductive polymers and organic computer devices. These can be formed into more flexible non-planar display surfaces and products such as clothes and curtains, see OLED display. Also see smart device.

Although mobility is often regardedby whom? as synonymous with having wireless connectivity, these terms are different. Not all network access by mobile users, applications and devices need be via wireless networks and vice versa. Wireless access devices can be static and mobile users can move in between wired and wireless hotspots such as in Internet cafés. Some mobile devices can be used as mobile Internet devices to access the Internet while moving but they do not need to do this and many phone functions or applications are still operational even while disconnected to the Internet. What makes the mobile device unique compared to other technologies is the inherent flexibility in the hardware and also the software. Flexible applications include video chat, Web browsing, payment systems, NFC, audio recording etc. As mobile devices become ubiquitous there, will be a proliferation of services which include the use of the cloud.citation needed Although a common form of mobile device, a smartphone, has a display, another perhaps even more common form of smart computing device, the smart card, e.g., used as a bank card or travel card, does not have a display. This mobile device often has a CPU and memory but needs to connect, or be inserted into a reader in order to display its internal data or state.