Although Apple's iPad is being credited with a paradigm shift from traditional PCs to smaller form factor touch devices, it was actually Apple's iPhone and iPod Touch that ignited the trend. Prior smartphones (notably the Palm Treo) led the way as general-purpose computing devices but the compelling design of the iPhone and iPod Touch and their emergence as important game platforms were the kindling for the fire.

As a result, it has now become fashionable to predict the demise of the computing platform that has been dominant for over 30 years, the traditional personal computer and the slightly more recent laptop personal computer. When one just looks around, it seems obvious - iPads, iPhones and their spawn abound.

It would be silly to try to deny the trend. However, those stirring these particular waters would have you believe that traditional PCs are on their way out. I doubt it, certainly for this decade.

Tablets like the iPad and tiny tablets like the iPhone have two great strengths - convenience and mobility. Despite the esteem in which these devices are held, their attributes are attained through compromise. In order to get great battery life, processing power is reduced. In order to get the convenient form factor and low weight, capacity is constrained. And because these devices do not include well-established input devices like keyboard and mouse and have less capability on the output side, the user's productivity is impacted.

Before I discuss productivity, let me provide some perspective on the output side of these devices by pointing out one technical specification of the iPad. The screen size is 1024 pixels wide and 768 pixels tall (when viewed in landscape mode). That screen size started becoming dominant in about 2000, 10 years ago; today the most common 4:3 size is 1280x1024 and the majority of laptops have a 16:9 or 16:10 screen (i.e., "HD") that is much wider.

Through the years, my displays have been getting bigger and bigger, not regressing to earlier, smaller sizes. That so many accept accept the compromise of less display space surely means that the convenience and mobility of small devices is compelling. I have no quarrel with that; it sounds perfectly reasonable to me.

Productivity

To illustrate my point about compromises in productivity, let's compare one person dashing off a text message with an iPhone and another doing the same with a full-sized PC with a keyboard. Assuming equal alacrity, I would expect the person at the PC to complete the data entry first, by a noticeable margin. For a few text messages limited to a few hundred characters the difference, while noticeable, will probably not be significant. But suppose a person texts 50 times per day?

The Web sites I build these days have back ends (based on my SiteCommander system) that allows my clients to maintain their own sites. Mostly the clients use a PC but a few have actually made changes using their iPhones. I've tried to make sure that SiteCommander remains accessible by small devices to accommodate such usage. However, I've also asked these clients about the experience. Specifically, I asked them if they were sitting with PC and iPhone both at hand, which would they choose to make the change to the site? In every case the answer was the PC. In every case the difference was the keyboard, mouse, and relative speed of completing the task.

In other words, the use of the iPhone was not preferred, it was simply convenient when the person was away from their PC.

It could be argued that convenience can be productive. For example, if you're out and about and you have a brainstorm, you can either make a note to take care of it when you are next with your PC or you can whip out the iPhone and do it on the spot. Jordan Lally, the songwriter and lead singer of the band Fiction 20 Down, almost always writes lyrics using his iPhone. This makes sense; as with any artist, who can say when the muse will strike? On the other hand, he writes them as emails, which means the content is easily transported to other computers.

Voice

The emergence of Siri for the iPhone is a significant event. Siri is an "assistant" that responds to voice commands. I have not tried this technology yet but Apple's promotion of the feature implies that you can talk to Siri just as you would a human assistant and you will be understood.

I'm going to assume that Siri works as advertised. For years, though, I've argued that talking to your device is not all it's cracked up to be. For example, if you're sitting in an airplane do you really want to speak "Buy 100 shares of XYZ when it drops to $5" or "Schedule my herpes test for Friday at 3?"

The very reason we have conference rooms and private offices and that we sometimes whisper is that many of the things we say are private, either personally or to a small group. These are not things we say aloud without regard to the setting. Will we change that behavior because Siri is non-human? I say no because it's not a question of to whom we are speaking but rather a question of what we are saying.

Power

There is certainly power in the ability to deal with matters instantly because you carry a device capable of connecting you to everything you need. Nonetheless, the higher productivity of a full-scale PC remains at least attractive if not important.

To me, this means that mobile devices will be an adjunct of traditional PCs for the forseeable future.

Just so I don't sound like some kind of curmudgeon, let me mention Arthur C. Clarke's personal computer of the year 3001 (3001: The Final Odyssey, the fourth and final book in the "2001" series). If you haven't read the book I almost hesitate to reveal this because it's part of the fun factor in the story [spoiler alert]. The computer is a form-fitting, personalized skull cap. Everyone shaves bald in order to wear the cap, which covers the head and is worn at all times except when sleeping. The cap provides world-wide communication and enormous processing power. It works via a man-machine interface (the cap connects "wirelessly" to the brain).

Fiction or fantasy? Suppose somebody had been handed an iPhone in 1940. They would have thought it impossible (or, as Clarke postulated, "indistinguishable from magic"). As far-fetched as the skull cap might seem today and considering the difference in size between typical computers of the '50s and the iPhone today, less than 60 years later, maybe Clarke's skull cap is even larger than the actual system will be a thousand years from now and maybe our progeny won't have to shave bald after all.

The key to the skull cap, of course, is that you communicate with it mentally, without spoken word. Power, but with privacy.

For now, I continue to think of this decade's crop of compact, mobile devices as useful, second computers. I think the traditional PC still has legs.