Devices

Devices

Wireless devices as they exist today will be obsolete by the time wireless communication becomes the status quo. Recall the desktop PCs with hard drives less than 1MB capacity and monitors with black screens and green lettering. This is how antiquated today's devices will seem in the next generations of devices and technology which presents quite a dilemma. Developers and designers have to make a decision: Code to existing devices to maximize their functionality, or code more generally so that as devices evolve, they will be compatible with legacy code. Unfortunately, the answer is both. In all fairness, it is virtually impossible to predict what the devices of the future will look like, how they will function, and how they will be used. However, developers must bear in mind that applications have to be scalable. Without a doubt, they will need to be scaled in the very near future.

The wired world sees computers and their components and accessories coming down in price rapidly. Their wireless counterparts are in such a state of flux that some pieces are dropping in price while others are temporarily rising. Consumers who buy the most recent devices on the market pay the early-adopter tax of expensive equipment and communications costs, as well as the tax of having devices that will not necessarily become the standard.

Cell Phones and Personal Digital Assistants (PDAs)

It is best to think of wireless devices in terms of the generation to which they belong. First-generation cell phones, for example, were popular in the last five years of the twentieth century (see Figure 1.3). These phones were analog, had poor reception, were typically large and cumbersome, and weighed more than the commonest second-generation phones of the early twenty-first century. Access plans were expensive per minute, coverage was strictly limited, and concepts such as browsing the World Wide Web on your phone were foreign and futuristic.

Figure 1.3. PDAs, cell phones, and wireless laptops

Towards the end of the 1990s, wireless network providers began to forge digital networks across the globe. These networks supported much sleeker devices, from digital phones with configurable ringing tones and primitive Web-browsing capabilities to PDAs in the form of Palm Pilots, BlackBerries, Pocket PCs, or Visors. These PDAs serve as combination organizers and limited computers. They afford early adopters the ability to browse the Web, albeit slowly, synchronize information between a PC and a PDA, and send text messages or e-mails via wireless networks. Hybrid devices are also available, combination mobile phones and PDAs such as the Microsoft Smart Phone 2002 and the Handspring Treo.

Several debates have ensued since the advancement of cellular phones and PDAs into a third generation of devices. Which will become the treasured device? Cell phones are decreasing in size but need larger display screens. PDAs are being produced with larger display screens but are not getting smaller. Will one become obsolete? Will they be interconnected with short-range wireless technologies so that the cell phone calls an ISP for a PDA to connect to the Internet? These answers may be known even by the time this text is published.

Third-generation devices, often referred to as 3G, are still in conceptual phases. While the world waits for better network operations and faster communication speeds, devices are being developed and tested. The initial wave of 3G devices is gaining market share.

Wireless Laptops

Another wireless device that bears mentioning is a wireless-enabled laptop (refer to Figure 1.3). Laptops are certainly heavier and much more cumbersome than phones or PDAs, but they perform with significantly higher capabilities and potential. They can serve as both connected and nonconnected devices, depending on where they are in relationship to a wireless network. Wireless LAN (WLAN) access via a laptop or desktop is becoming an attractive alternative to the cluttered, cable-ridden offices that are the norm. Each of these technologies will need to be compatible with wireless systems, which introduces the first security problem into the mix.

The numerous devices, software available on devices, networks, service providers, vendors, device manufacturers, implementations, and technologies expected to interoperate in the wireless world present a serious risk. For all systems to be compatible with one another, holes will inevitably be left open. Several characteristic features of wireless devices will continue to evolve.

Consumer Issues

When examining device characteristics, there are consumer issues and technical issues. Some consumer issues cross over into technical ones, and vice versa. For the sake of discussion, though, it is easiest to distinguish consumer issues as those usability and external functionality issues associated with a wireless device. Technical issues are those issues concerning operation of the device, the hardware it comprises, and the software that runs on it. Consumer issues are important to consider in making purchasing decisions for consumers and businesses alike.

Display Screen and Input Devices

The most obvious characteristic, frequently given only cursory attention, is the size of the display screen on a wireless device. Anyone who has attempted to run an application or use functionality on a device can attest that the screen size is a limiting factor if it is not large enough. Factors that are not always considered but have implications for development are

         Resolution

         Colors

         Behavior under certain conditions, such as heat (left on a car dash in the summer) or cold (left in a trunk during the winter)

         Backlighting

         Contrast

         Behavior with different amounts of light

Another related issue is how a user operates the device. Some devices work with numeric keypads, some with touch screens and a stylus, some with detachable keyboards. All these seemingly insignificant factors contribute to a device's functionality and should be considered when choosing devices for specific scenarios.

Peripherals and Expansion

Peripherals and expansion are important consumer issues to consider. If a device has the capability of having components attached to it, it provides extra functionality but also potential vulnerabilities. Peripherals, for example, can turn cell phones into PDAs or give PDAs modem capabilities. By extension, cell phones could become scanners, credit card readers, or cameras, given the right equipment. Not all devices have this capability, and depending on system and user needs, the ability to add external interfaces or functionality may be adding value or creating danger. Some technologies, such as Bluetooth, a short-range wireless technology, open the possibility for devices to become peripherals of one another, enabling users to customize on-the-fly configurations to suit their needs on a changing basis.

Transport

A definite consumer issue is that of transportability. Can I fit the device in my hand? my pocket? or my briefcase? Each option comes with its own constraints and benefits. If a device can be held in one hand, it can be transported easily. It can also, however, be easily stolen, lost, or perhaps broken. Devices that fit in a briefcase are less likely to be lost or misplaced and offer greater potential for processing and storing information. These devices are more attractive to a user who is more concerned with performance than portability. Features inherent to each device make its users more or less able to perform desired tasks. If a user does not save time and energy with a device, she will discard it quickly in favor of one that is either more portable or more capable.

Battery Life

The single biggest limiting factor in wireless devices is physics the battery. If the Energizer bunny were wireless, devices with wireless capabilities would take on a new life of their own. As for the "It keeps going and going" part, batteries in wireless devices do nothing of the sort. Unbeknownst to the novice user, the types of applications performed on a device directly affect its battery life. A cell phone in use takes far more battery power than a cell phone lying idle. A PDA can outlast a cell phone in terms of power and lifetime, but its applications have to be developed with careful consideration to battery usage. Security capabilities can be significant drains on battery power and can be discarded as wasteful in favor of faster processing without functions like robust encryption. (See Chapter 6, "Cryptography," for a more detailed discussion.)

Communication

Some wireless devices include a property known as peer-to-peer capability. This capability enables device users to form fast, easy connections with each other and to "beam" information to each other. The peer-to-peer feature makes use of an infrared (IR) port on a device, allowing users, in effect, to create their own personal networks. IR communication requires that users be within a short distance of each other but offers significant, attractive possibilities. One limitation of this type of communication is that systems built to make use of IR are often closed systems. Palm and Microsoft systems are closed and therefore cannot talk to each other. Most of their applications use the same standards for transport but not for application exchange. This prevents communication across platforms. If one user has a Palm Pilot, she can likely talk to other Palm users but not necessarily to someone with a Pocket PC. If each device ran an application that enabled the two to exchange information, it would be possible, but the operating systems themselves could not interact. This technology has not been fully developed and may not come to fruition before other forms of wireless networking do. The idea is popular, however, and should be considered when developing wireless applications.

Technical Issues

All operating systems (OSs), development tools, applications, and browsers present complex issues to be investigated. Until one device or operating system manufacturer begins to assert itself as an authority or leader, all of them will be limited in their capability to operate seamlessly with others. Palm Pilots operate with Palm OS, RIM BlackBerry devices operate with their own proprietary operating system, and Pocket PCs operate with the Microsoft platform Windows CE. Some vendors produce devices and license these operating systems for their own use, but these are not highly configurable and are best used as they are delivered. Each device has its own niche in the current market. Palm is easy to use, RIM allows wireless e-mail access, and CE is highly compatible with Microsoft products.

Software Development Kits (SDKs) are another important factor to investigate when examining a device. If application designers find more comprehensive SDKs for one device than for another, they may choose to streamline their development process and gear applications to the device with the better SDK.

When considering all the ramifications of analyzing a device, it is important to note the three major players involved: the hardware manufacturer for the device, the operating system or software vendor, and the wireless network service provider. The hardware manufacturer has extensive control over what can go on the device. In most cases, this company provides a limited set of options from which service providers can choose. Often, too, a partnership exists between the operating system vendor and hardware manufacturer (or the two may be from the same company). The joint OS and hardware production efforts present options to service providers, who choose limited customization options.

The browser, for instance, on a mobile device such as a cell phone or PDA is preconfigured when it is purchased, and the ability to update it is still evolving. Surely, in the near future, this will be a must in devices. The ability to tweak the software installed on a device is a necessity for properly protecting oneself from discovered security vulnerabilities. Just as in the wired world, there will be patches and updates, and there will need to be easy ways for them to be applied by average users. Currently, some devices allow this capability with hardware that can be connected to a PC, but the demand for faster, wireless methods of doing so is increasing.

In the cell phone realm, for instance, one wireless service provider's phones come with a software application that provides a type of list to the device, including identification information about those bearers with which the phone can communicate. As new bearers are installed, the software must be updated for the phone to be able to communicate with the new towers. Currently, this function can be performed only at a retail store or an authorized reseller. Updating this software is a cumbersome and undesirable process. If the software could be updated transparently each time a person initiated a call, say, on the first of each month, the device would be more attractive. Also, the device would incur a new set of security risks.

The service provider often dictates which features will be available on a device in order for it to agree to provide service for device owners. This can be something simple, such as the preset bookmarks in a browser, or something more complex, such as limiting the gateways the device can access to the provider's own.

The involvement by each of these entities in configuring devices is often at the expense of a user's ability to customize a device or protect herself against compromise. In most cases, this cannot be prevented, but it is important to remember when assessing the risks involved in a certain system.