Jim argues that one of the biggest problems with UPCs is their battery life; he points out that the Vulcan FlipStart device will last for just two hours, while the OQO device is expected to last for four hours. I agree that four hours may actually be around half of what the class needs. However, fuel cell technology is improving and expected in the market in 2005 from such companies as Toshiba, and in the meantime, you can buy and carry spare batteries; many airlines also have power available. Also, the majority of these devices will drop into a lower power mode for PDA and multimedia functions, which could extend the effective battery life significantly. For instance, if you were just listening to music the battery life could exceed that of an iPod as long as you left the screen powered down. How each vendor addresses the power problem will be one of the big differentiators once UPCs hit the market.Finally, think subsidies. These new devices are e-mail engines and ideally suited for the wireless networks being rolled out internationally. Much like cell phones today, they could be attractive to carriers who want to drive data use and could easily be subsidized. In the case of an airborne wireless service, like Boeings Connexion service, they could be handed out to folks who dont have wireless laptops so they could make use of that service in flight. On the ground, they could be rented in places like Starbucks.Challenges to Overcome People dont always embrace new designs when they first come to market. Sometimes thats temporary, other times more permanent. SUVs and minivans eventually caught on, while the Newton is still seen as a curiosity. This class of computer is either too big to be a handheld, and too small to be a laptop. While Japan has experimented with small laptops for years they just havent been popular in Europe or the United States. In fact, ultralight laptops, which are much larger than this new class, havent been able to manage more than 20 percent market share and have been well below 10 percent for much of the last decade. Its all perception, though. As users realize that they need to read more than they have to write, these devices will become more palatable. Add in attachments like keyboards, mice and monitors, and theyll become even more useful. With one device you dont have to sync, and unlike the BlackBerry, youll always be able to open all attachments. For IT this means we are back to one image and one device per employee. That cuts down on complexity and makes mobile users easier to support. It also improves security because it reduces complexity, and complexity increases security risk. Jim argues that people dont like all-in-one devices, and in most cases he would likely be right. Certainly in the kitchen, refrigerator/stoves and dishwasher/storage drawers (I actually have the latter) havent exactly set the market on fire. But I have portable DVD players, PDAs, cell phones, and laptops. And, frankly, Im starting to feel like Quasimodo when I lug this stuff around. Going through security at airports has become a nightmare as I have to remember to take all of this stuff off, and then not leave it behind when I leave the security station. If there was an adequate all-in-one device, Id likely buy it myself. But the key word is "adequate." I still dont think the UPC will replace the cell phone. However, Jim should remember that the PC itself is an all-in-one device that is quickly gaining phone capability through VOIP, and has been increasingly becoming a full consumer electronics device over the last several years. Next page: Looking ahead to the future.