PC makers are exhibiting worrisome signs of the same kind of calcified thinking that has brought the U.S. auto industry to its creaking knees.Echoing consumer demand for more fuel-efficient vehicles, PC buyers are looking beyond traditional bloatbooks, and snapping up a newer class of lightweight notebooks. And that has PC makers worried, according to The New York Times.

These more-energy-efficient ultra mobile PCs, sometimes called ultra mobile PCs (UMPCs), or mobile Internet devices (MIDs), are a product category that isn't yet clearly defined, but Bill O'Brien takes a crack at it:

The one thing to remember is that UMPCs are niche devices. They're trying to be something more than a PDA, but not quite a PC, and they're almost succeeding ... the only real distinction right now seems to be that if they're Windows-based you call them UMPCs, but they're MIDs if they run Linux; they are doing an excellent job of muddying the water.

If consumers are buying these power-sipping clamshells and tablets, then they're not buying traditional notebooks, the thinking goes. But not all UMPCs and MIDs are bought as notebook-replacement units. They're also being bought as alternate devices, for checking e-mail without having to boot up Windows, for example.

Instead of rejoicing that a new device market has dropped into their laps, many PC manufacturers are whining about cannibalized notebook sales and low margins. That's like a Honda dealer crying about stagnant Pilot (SUV) sales while he's breaking sales records for moving Honda Civics.

Some of these devices -- you also can call them netbooks or micro notebooks -- eventually will replace shoulder-separating workhorse notebooks crammed with apps. The streamlined machines, some of them running Linux, will plug into the cloud to connect with apps. In fact, a new, slimmer, trimmer version of Ubuntu, called Netbook Remix, and built for this purpose, is ready now.

PC makers need to wipe away their tears, and -- like the scrambling auto industry -- shift gears and try to catch up with what consumers really want: task-specific, energy-efficient devices.