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B U Y E R ' S G U I D E

Networking in the Palm of Your Hand

August 5, 2002
By Sean Ginevan

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Data Sync, Expansion

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	In this article
	Introduction
	Data Sync, Expansion
	Pick a Platform That Suits Your Philosophy
	Major PDA Operating Systems
	Interactive Buyer's Guide
	PDAs
	Chart
	Customize Chart
	Product Directory
	Search

As important as OS features is data synchronization. Both Microsoft ActiveSync and Palm HotSync programs can use serial, USB, Ethernet, 802.11b and other media to synchronize data. However, the similarities between the two end there. ActiveSync automatically detects a connection between the host PC and the PDA, and synchronizes data automatically. If the connection is established and a user changes information in Outlook, the PDA will receive the updated data automatically. ActiveSync synchronizes data only from the PIM portion of the PDA (Outlook, My Documents and so on). This means that data can be lost despite having been synchronized.

Unlike ActiveSync, HotSync synchronizes all data (including installed applications) on the PDA. But synchronization does not occur automatically; it happens only when the HotSync program is run by executing the program on the PDA or by pressing the HotSync button on the cradle.

In the enterprise market, synchronizing data between one host computer and one PDA is becoming passé in favor of centralized synchronization and management. Several companies offer management servers that let IT departments centrally distribute applications to PDAs at one time. PIM sync servers are also available and let IT departments distribute information from a database or groupware system directly to a fleet of PDAs (see review, "Enable Your Mobile Apps").

As if the variety of OSs weren't confusing enough, a host of expansion options is available. The most popular standards are MMCs (multimedia cards), SD (secure digital) cards and Compact Flash cards. MMCs are nonvolatile (data is not lost when power is cut) cards used to store data. Capacity ranges from 16 MB to 64 MB, and transfer rates go up to 2.5 MBps.

The successor to MMCs, SD cards, has capacity from 16 MB to 512 MB and a transfer rate of up to 10 MBps. SD also supports content encryption to ensure copy protection and can be used for I/O expansion, as demonstrated by the Palm/ Toshiba SD Bluetooth card. With prices of SD and MMC similar, the SD cards are a better investment.

Compact Flash cards have a capacity ranging from 16 MB to 1 GB and a transfer rate up to 3.5 MBps. They are also used for I/O expansion, as with Symbol's Spectrum24. Compact Flash has the most versatility for I/O applications and offers more storage, so if you are concerned with expansion, go with Compact Flash.

Networking Options

Once you have chosen a PDA platform, how do you connect it to the network? Among the options are infrared, Ethernet, 802.11b, Bluetooth, wireless WANs and modems. These are all supported by Palm and Pocket PC. Many Linux devices have support for some or all of these networking standards.

Which networking solution is right for your enterprise? That depends on your requirements. Ethernet has great speed but leaves users tethered to cables. Infrared operates at relatively slow speed and requires line of sight, but it allows for more mobility. 802.11b and Bluetooth allow for mobility but are vulnerable to RF interference (a big issue for manufacturing environments). Wireless WAN access may not be available in all areas, can be expensive and is slow.

For the security conscious, VPNs can be implemented for use with PDAs. In addition to Microsoft's integrated VPN client, third-party solutions, such as Certicom's movianVPN, are available for Pocket PC and Palm. From a performance standpoint, Pocket PC 2002 tends to have better network I/O performance than Palm. This may be because the Palm OS was not designed with high-speed networking performance in mind. Performance may increase with Palm OS 5, though there are now no clear performance tests for Palm OS 5 or the various Linux OSs.

What The Future Holds

Mobile computing will grow beyond PDAs in the next few years. Intel's X-Scale architecture promises to increase the speed of mobile devices. Already we are seeing PDAs and other devices like cellular phones converge into all-in-one mobile devices (see buyer's guide, "It's a PDA! It's a Phone! It's a Data-Enable Cell Phone"). Microsoft's tablet PC may offer even more versatility for mobile devices as it blurs the line between PDAs and laptops. Only time will tell how much the role of mobile devices in the enterprise will increase.

Sean Ginevan is a research associate with the Center for Emerging Network Technologies at Syracuse University. He has conducted research in convergent multimedia and electronic books, and has spoken at Dickinson College and the National Archives College Park on oral history and the Web. Send your comments on this article to him at sean@ginevan.com.