What is mobile Computing?

Mobile Computing is a generic term describing your ability to use technology to wirelessly connect to and use centrally located information and/or application software through the application of small, portable, and wireless computing and communication devices. This includes devices like laptops with wireless LAN technology, mobile phones, wearable computers and Personal Digital Assistants (PDAs) with Bluetooth or IRDA interfaces, and USB flash drives.

History of mobile devices
Originally, electronic devices such as radio transmitters, wireless communications systems, and the like, were base stations, operated at fixed locations, typically with large antenna towers. Widespread use of automobiles gave rise to smaller devices operating at 6 volts. In the 1950s, the transition to 12 volt automotive electrical systems gave rise to a large number of 12 volt devices, such as two-way radios, referred to as mobile rigs. A large industry, with companies such as Motorola (Motor-ola) sprung up to support the growing need for mobile devices, such as taxicab radios, police radios, and other 12 volt underdash equipment, as well as trunk mount systems. Today there are a wide variety of mobile computing platforms, including dash-mount VGA displays, and computers that can provide GPS and other navigation functions for automobile users.

Base-Mobile-Portable hierarchy
In ham radio, there is a base-mobile-portable hierarchy, as follows:
Base station: fixed location, incorporated into a building or other architecture;
Mobile: attached to or in a vehicle or used by a mobileer:
Portable: worn or carried. (The word "portable" derives from French "porter" = "to wear", but also includes handheld devices such as handie-talkies, walkie talkies, handheld computers, as well as wearable computers).

Blurring the boundary between mobile and portable
Around the early 1980s the boundary between "mobile" (vehicular) and "portable" (wearable or hand-held) computing platforms began to blur. This started with the so-called "bag phones" that had a cigarette lighter plug for automotive use, but were small enough to carry around for portable use. Thus there began a blurring in both use, as well as terminology, between mobile devices and portable devices. 12 volt mobile phones began to be used as portable phones, and similarly 12 volt portable computers, such as the Osborne, began to appear. These could be used in a vehicle, from the vehicular power source, or could also be carried around by a pedestrian. Today, there is a fuzzy boundary between mobile and portable wherein many small handheld phones and computers will operate on 12 volts from a cigarette lighter socket, as well as from self contained batteries. Presently almost every vehicle currently manufactured has numerous onboard computers. There is also a proposal to have these connect by wireless ad-hoc networks, to form what would likely be the world's largest network. Since we are almost never away from someone's car somewhere, we could also use such a network to link to portable handheld or wearable computers, and thus have a near complete coverage of most urban or suburban areas.

Mobile Computing: In-Vehicle Computing and Fleet Computing
Many commercial field forces deploy a ruggedized portable computer such as the Panasonic Toughbook 29 with their fleet of vehicles. This requires the units to be anchored to the vehicle for driver safety, device security, and user ergonomics. The rugged laptops are rated for severe vibration associated with large service vehicles and off-road driving, and 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 Toughbook R&D).
Vibration: Vehicles typically have considerable vibration that can decrease life expectancy of computer components, notably rotational hard drives.
Daylight, or sunlight readability: Visibility of standard screen 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.
Several specialized manufacturers such as 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 USAT Corp. and TouchStar Pacific specialize in architecting 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 WAN modem, power conditioning equipment, and a WAN, WLAN, and GPS antenna mounted external to the vehicle.