Nine days with a Treo 600 wasn’t enough to convince me that I should jump on the bandwagon. At the same time, it was entirely too long.

I completely understand the desire to combine multiple gadgets into one. I don’t really care to carry a phone, a PDA, and an iPod everywhere I go. Yet, I do, and it’s because at this point each of those devices is optimized for what it does. There are competing pressures when you attempt to combine them. For example:

Screen size – The size of the screen on a music player isn’t terribly important. The smallest screen you’d want on an iPod is not all that much bigger than the screen on a mobile phone. However, all the rage seems to be combining a PDA with a mobile phone, as with the Treo devices. On the one hand, the Treo’s display is too small to make a good PDA. On the other, the Treo’s display makes it entirely too big to be a phone.

Battery life – As long as my phone will survive three days in standby with an occasional call, I’m happy. The PDA should be able to go at least a couple of days with moderate use. However, a music player wants every drop of energy you can give it. My iPod mini won’t last more than five hours, and usually not more than four. That’s a bit frustrating, but I can’t even imagine how much shorter it would be if it had to drive either a radio or a big PDA screen, as well.

Overall size – This is related to screen size, but of course includes the bulk added by the battery, as well. A device that combines an adequate screen and battery to be a PDA or a music player doesn’t have much room left to add a mobile phone radio. I’m curious as to how the announced-but-not-yet-available Motorola iTunes phone will work out. Is the delay in rolling out this device political (RIAA, et al), or is it technological? I’m starting to think that it’s the latter.

I don’t see any way to resolve these issues with current technology and approaches, whether they are used in current production or on the near horizon. In fact, I’m pretty well convinced that we’re going to need a paradigm shift. We’re entirely too dependent on visual interaction with these devices, and for very good reasons; it’s simply more efficient to give the users of these devices visual feedback from a both both practical and tech viewpoints. Speech generation and recognition is getter better all the time. Even so, it still has a long way to go to scale to devices like these.