We face similar challenges in today's mobile computing space. Traditional LANs and WANs have evolved to the point where users are not so reluctant to be dependent on the availability of those network services to get their work done. In many organizations, the network is viewed as a utility, much like the telephone or the electrical distribution system. System availability is measured in nines, as in 99.999 percent. We have developed the management discipline to deliver high availability, and the technology is there as well. But that just isn't the case for mobile systems.

When designing mobile applications, there is a need to focus much more on disconnected operations. The infrastructure needed to provide 99+ percent availability of mobile network services simply isn't there today, and it won't be for the foreseeable future. Thus, the assumptions of network availability that have driven so much progress in the information industry over the past 20 years are suddenly irrelevant. Yet, I'm not so sure that many IT professionals, let alone companies that specialize in mobile technologies, fully appreciate all the implications.

Recently, we've spent some time working with Handspring's new Treo smart-phone, a device that integrates a cell phone and a PalmOS computer into a single device. The form factor is elegantly designed, and Handspring deserves credit for a solid job of engineering. But when we fired up the e-mail system, we discovered that it was based on the POP3 mail protocol. Now, if I was carrying a notebook computer around and doing all my mail processing from that device, POP3 would be ideal. I could connect to the network, download all my mail, disconnect, compose responses offline, reconnect and send. But the Treo is not, and for most people cannot be, the primary mail machine. It lacks adequate storage capacity, the underlying wireless networking is too slow and people can't really be expected to use that tiny keyboard for all their messaging. Clearly, users need something more sophisticated.

A number of vendors have given a lot of thought to this challenge. Seven Networks, for instance, has developed a mobile messaging system that takes a different approach. Rather than downloading all new mail via POP, Seven provides a window to the user's desktop e-mail system or, alternatively, to an Exchange server. When Sprint and Cingular begin offering this service, subscribers can use those carriers as a secure conduit to their native mail environment. In fact, Seven goes beyond simple mail, providing users access to file systems as well. It's very cool technology, but there's a catch. The Seven paradigm is great for as long as you have mobile network connectivity, but it provides no solution for disconnected operation. If users can't process mail while in flight from New York to Los Angeles, the problem hasn't been solved.

One solution we've been fairly impressed by in the labs is mobile synchronization software from companies like Extended Systems and Synchrologic. These companies start from the assumption that mobile device connectivity will be intermittent. So, rather than provide real-time access, the software periodically synchronizes the mail store on users' mobile devices with the mail store on their home systems. Best of all, that synchronization can take place through wired or wireless networks; the system doesn't care.

It's a solid solution. But, of course, there's a catch. If your volume of e-mail is significant, you'll still need considerable local storage resources on the mobile device. The good news is that most of the new generation Pocket PC and PalmOS devices provide storage expansion slots and that solid-state flash memory is very inexpensive these days. Unfortunately, among the wonderful smart-phones from Handspring, Samsung and Kyocera Wireless, not a single one has memory expansion capabilities.

For more information on Seven Networks' mobile messaging system, go to:
http://www.seven.com/lvl2.jsp?menu=news&sec=article&newsobj_id=1010449442036

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