Mobile and wireless devices are fast becoming first class citizens of the Internet as well as of corporate enterprises. The device landscape, once dominated by personal computers (PCs), is becoming littered with a variety of different form factors, user interface (UI) paradigms, and vertical market use cases. This is not surprising as we have always shared our homes and offices with a multitude of "things" alarm clocks, boom boxes, stereo systems, telephones, printers, televisions, and many more.
What is changing, however, is that these "things" are becoming digital and digital platforms that are capable of receiving renewable software, content, and services, which can then be delivered to the user through the device's unique ergonomics and form factors. Not only is there emerging a large number and variety of these digital platforms, but device add-ons, such as bar code scanners and cameras, are further enhancing the capabilities of these digital platforms.
A personal digital assistant (PDA) that was once used for appointment and contact management can now be augmented with a bar code scanner add-on and be used to track and manage inventory. The same PDA can have its abilities further increased with a digital camera add-on to take, edit, and annotate pictures. Add-ons not only enhance the capabilities of each device, but also the number and type of software and services that the device can usefully run.
Many of these devices are being developed to support wireless connectivity because the lack of wires simplifies their configuration and use. With wireless capability, users do not have to worry about having the right connectors or the right cables. There is no need to purchase network hubs or routers as more devices are added. Within homes and offices, there is no need to figure out how to route cables from one machine to another machine, which may be in separate rooms.
It is important to note that wireless and mobile are not the same: wireless does not necessarily mean mobile. As shown in Figure 10-1, the classic example of this is a standard television set. Receiving television programming signals over the air certainly makes televisions wireless, but their one-hundred to two-hundred pound weight does not qualify them as being very mobile.
Figure 10-1. Wireless devices are not necessarily mobile.
Mobile devices are those devices that can be easily used anywhere in any situation. They do not require special configurations of their users. Instead, all of the devices' capabilities can be used while the user is "on the go."
In order for devices that support communications with other devices to be considered mobile, they have to use wireless connectivity. Clearly a physical cable cannot tie down a device that can be used while "on the go." Wireless connectivity also allows the user to access any information at any time, thus ensuring that all of the capabilities of the device are available no matter where the user is.
A cellular phone is mobile. A mobile phone can be used wherever there is cellular wireless network coverage. While within these coverage areas, mobile phones allow users to utilize their capabilities while sitting down, walking, or even while driving a car. Voice-based dialing features and hands-free headsets further cement cellular phones' position as mobile devices.
On the other hand, contrary to popular belief, laptop computers are not mobile. At the very least, laptops require their users' laps, thus necessitating that users be sitting or kneeling. Using the laptop's keyboard also requires at a minimum one hand, and ideally two to be more productive. Using a laptop anywhere in any situation, say, while walking, is not practical. Laptop computers, even those with wireless connections, do not fit within the definition and requirements of mobile devices.
Although many of the concepts and issues we discuss herein are relevant for both wireless as well as mobile devices, in this chapter we focus on mobile devices. Their small form factors and simplified usage paradigms allow mobile devices to be used seamlessly in all situations, while pervasive wireless networks enable these devices to access information and communicate from anywhere.