Another family of devices that is rapidly changing the way that we communicate and connect to network resources is the personal digital assistant. So, what is a Personal Digital Assistant (PDA)? PDAs started out as handheld devices that made it convenient to take information such as addresses, phone numbers , and appointments on the road. These devices were really just electronic organizers with a limited amount of memory; however, these early PDAs still provided a user with the ability to sync with Personal Information Managers (PIMs), such as Microsoft Outlook and Lotus Organizer (or PC-based programs included with these handheld devices that provided address book and calendar features).
PDAs have evolved into handheld computers, and for our purposes we will limit our discussion of PDAs to devices that actually have processing power (meaning you can manipulate data, even send and receive data, on the PDA without being attached to a PC). This means that the PDA must have a processor, memory, and an operating system.
PDAs are basically built with two major designs in mind: handheld pen devices and slightly larger units that provide an attached keyboard (although keyboards are available for nearly all the PDAs as add-ons). PDAs come in a variety of sizes and price ranges. For example, the Palm Pilot, which runs its own Palm operating system, provides a range of devices that vary in functionality and price. Other PDAs that also run the Palm OS include devices from Handspring (which recently joined forces with Palm) and Sony. Figure 17.9 shows a Handspring Visor Deluxe, which uses the Palm OS and provides an expansion port for add-on devices, such as a modem and a cellular phone.
Figure 17.9. PDAs such as the Handspring Visor are pen-based, handheld computers.
Another family of PDAs runs the Windows CE .NET operating system. A number of companies have handheld devices on the market that run the Windows CE .NET OS, including Microsoft, HP, Compaq, Casio, and Hitachi.
Applications on a Windows CE device are launched either via the Start menu or by using icons on the desktop. Figure 17.10 shows the Windows CE desktop on an HP color handheld device.
Figure 17.10. Windows CE handheld devices provide the familiar Windows environment.
PDA and PC Synchronization
PDAs are designed primarily for offline "on the road" computing. However, PDAs outfitted with a modem or cellular connectivity technology can connect to a service provider and access email or the Web, or even the corporate network. For example, in the Windows CE environment, Microsoft has developed a Terminal Server client for Windows-based PDAs. This allows these handheld devices to become mobile network clients that can directly access network applications using a modem or wireless connection.
In most cases, however, the most common method of moving information to and from the PDA is synchronizing the PDA with a PC. For example, in the Palm environment, the Mail, Address Book, and Calendar applications can all be synchronized with the different services provided by Microsoft Outlook (Inbox, Contacts, and the calendar). In the Pocket PC environment, the pocket version of Outlook can be synchronized with the desktop version of Outlook on the PC.
The implication of synchronization is that information temporarily held on the PDA ends up on the desktop computer. What's more, if the computer is connected to a network where groupware applications such as Outlook are used to share calendar information, the PDA information will eventually dovetail with information that can be accessed by different users on the network (in an environment where groupware applications are being used).
In fact, Palm has developed an Ethernet cradle; Palm devices placed in the cradle can be synchronized directly on the network using Palm's Hotsync Server software. This means that a network administrator could allow users to sync their Palm devices with groupware applications found on a Microsoft Exchange Server or in a Lotus Notes environment. The Hotsync Server software allows handhelds to be basically managed like any other device on the network.
Synchronizing a PDA with a PC typically requires a physical connection. All the PDAs available support serial synchronization, where a connection is made between the PDA and a COM port on the computer. Many PDAs also can be synchronized to a PC or Macintosh computer via a USB connection.
In the case of both Palm OS-based handhelds and Windows CE devices, the synchronization software is part of the default application installation on the PDA itself. The software that resides on the PC has to be installed and is typically provided with the PDA on a CD-ROM. Synchronization itself can be initiated from the PDA; in many cases, a button on the sync cradle begins the sync process. The sync software residing on the PC can also be used to initialize synchronization between the PDA and the PC.
Before leaving the subject of PDAs, we need to take a look at relatively new technology called BlackBerry. BlackBerry, developed by Research in Motion, Limited (or RIM as it is often referred to), provides a wireless (and secure) environment that allows a BlackBerry device to access email, the Web, and other communication services. While many cellular providers are providing connectivity for BlackBerry devices, a company can actually deploy its own BlackBerry server, which provides wireless connectivity directly to the corporate network.
BlackBerry devices can access communication platforms such as Lotus Domino and Microsoft Exchange. This means that a BlackBerry user can directly connect to network messaging services such as email and scheduling. BlackBerry devices can also access Web data, and most of the newer BlackBerry devices provide cellular phone support.
BlackBerry devices provide a simple-to-use operating system and a full functioning keyboard. Figure 17.11 shows the BlackBerry 6700.
Figure 17.11. BlackBerry devices provide an easy-to-use operating system.
BlackBerry devices are now being made available by a number of cellular phone providers such as T-Mobile and AT&T. Compaq and other makers of PDAs are also creating new handhelds that provide BlackBerry support. BlackBerry devices are even sold by Internet service providers such as Earthlink in combination with connection packages that provide wireless Web access and access to email accounts provided by the ISP.