Mobile computing

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Mobile computing is a generic term describing one's ability to use technology while moving, as opposed to portable computers, which are only practical for use while deployed in a stationary configuration.

Many types of mobile computers have been introduced since the 1990s, including the:

[edit] Technical and other limitations of mobile computing

Insufficient bandwidth

If the user needs access to a network such as the internet on the go, they must resort to slow wireless WAN systems primarily intended for telephone use. Higher speed wireless LANs are only available in specific sites

Security standards

When working mobile one is dependent on public networks, requiring careful use of VPNs.

Power consumption

Since the grid can not be used, mobile computers must rely entirely on battery power. Combined with compact size, this means unusually expensive batteries must be used

Transmission interferences

Weather and terrain problems as well as distance-limited connection exist with some technologies. Reception in tunnels and some buildings is poor.

Potential health hazards

Potential health damage from cellular radio frequency emission is not known yet. However, more car accidents are related to drivers who were talking through a mobile device. Also, cell phones may interfere with sensitive medical devices.

Human interface with device

As HMDs are still uncommon, screens are often too small. Keyboards are impractical, especially one-handed, and alternate methods such as speech or handwriting recognition require training.

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T Imielinski, BR Badrinath "mobile wireless computing, challenges in data management- Communications of the ACM, 1994 - portal.acm.org

[edit] Mobile computing: in-vehicle computing and fleet computing

Many commercial and government field forces deploy a ruggedized portable computer such as the Panasonic Toughbook or larger rack-mounted computers with their fleet of vehicles. This requires the units to be anchored to the vehicle for driver safety, device security, and user ergonomics. Ruggedized computers are rated for severe vibration associated with large service vehicles and off-road driving, and the harsh environmental conditions of constant professional use such as in EMS, fire and public safety.

Other elements that enables the unit to function in vehicle:

Operating Temperature: A vehicle cabin can often experience temperature swings from -20F to +140F. Computers typically must be able to withstand these temperatures while operating. Typical fan based cooling has stated limits of 95F-100F of ambient temperature, and temperature below freezing require localized heaters to bring components up to operating temperature(based on independent studies by the SRI Group and by Panasonic R&D).
Vibration: Vehicles typically have considerable vibration that can decrease life expectancy of computer components, notably rotational storage such as HDDs.
Daylight, or sunlight readability: Visibility of standard screens becomes an issue in bright sunlight.
Touchscreens: These enable users to easily interact with the units in the field without removing gloves.
High-Temperature Battery Settings:. Lithium Ion batteries are sensitive to high temperature conditions for charging. A computer designed for the mobile environment should be designed with a high-temperature charging function that limits the charge to 85% or less of capacity.
External wireless Connections, and External GPS Antenna Connections: Necessary to contend with the typical metal cabins of vehicles and their impact on wireless reception, and to take advantage of much more capable external tranception equipment.

Several specialized manufacturers such as National Products Inc (Ram Mounts), Gamber Johnson and LedCo build mounts for vehicle mounting of computer equipment for specific vehicles. The mounts are built to withstand the harsh conditions and maintain ergonomics.

Specialized installation companies, such as TouchStar Pacific, specialize in designing the mount design, assembling the proper parts, and installing them in a safe and consistent manner away from airbags, vehicle HVAC controls, and driver controls. Frequently installations will include a WWAN modem, power conditioning equipment, and WWAN/WLAN/GPS/etc… transceiver antennæ mounted external to the vehicle.