It is clearly the era of miniaturisation. Today, when cell phones, smart phones, PDAs and notebook computers are as common at the corner coffee shop as they are in an office set-up, the ranks of the mobile workforce have formulated some opinions about the ideal mobile device.

The only problem may be that each worker's ideal device has a different set of functions from the next worker.

Result: having a mass favourite is close to impossible.

But a few companies think they know what legions of consumers and mobile workers really want. Their answer -- the ultra-mobile personal computer.

Smaller than a notebook, bigger than a PDA and most often not including any kind of phone, this is a full-fledged PC running a modified Windows XP Tablet PC edition (now Vista) operating system, which makes it capable of running any application made for Windows XP.

Typically, it is a steno-pad-size device that can stream video from the Internet, providing users with a mobile entertainment experience.

"Ultra Mobile PCs overcome the computing limitations of handheld devices such as PDAs and smartphones, while simultaneously addressing the mobility constraints of PCs," notes market analyst In-Stat.

It also predicts that the UMPC market will touch the 8-million mark by 2011, provided it gets the thrust from industry heavyweights such as Microsoft and Intel.

Sony, Fujitsu and Samsung have started work in this category, and analysts maintain that the competition between these players will be fierce and thereby beneficial for the consumer.

In terms of processors that power any mobile device, Intel will be going up against a different competitor, Via, the Singapore-based maker of low-power x86 microprocessors.

Although Intel is aggressive within the UMPC market, "the processing solution will have to meet increasingly stringent power requirements as improvements in battery technology are not advancing at the same pace as the requirements", says In-Stat's report on the market.

However, Gartner deems the UMPCs as a "lifestyle category, not just another hardware form factor." As such, UMPCs let users store and carry their digital "stuff" such as photos, videos and MP3 files, and would function as a real-time email client, Gartner states.

In-Stat, meanwhile, contends that though UMPCs might not sport any killer features yet, they will still have the effect of "building a new usage model around defined price points".

One might wonder if there really exists a need for a device that sits between an ultra-portable notebook and a fully featured PDA?

Sachin Thapar, head (IT sales and marketing), Sony India quips, "The UMPC is a device that is purchased in addition to the notebook users already own, and is small enough to fit in a small backpack or purse."

It is completely justified for consumers to expect this Rs 1 lakh UMPC to run Windows Vista's AeroGlass interface just as fast as dual-core notebook, a permanent connection to the Internet, a GPS navigation device, a slim solid state disk and a battery time of eight or more hours, but the hardware and software just isn't there yet.

Thapar makes his point: "Our mini-PCs, like Sony Vaio UX and TX, may have value in semi-vertical segments such as field sales and education."

Students, he feels, stand to benefit with a product like Vaio UX which is both trendy and a powerful entertainment handheld device. A mobile workforce, on the other hand, should find solace from Sony's Vaio TX that is nothing but a miniaturised notebook.

A typical UMPC packs in a touch-screen, a compact LCD display that can be operated with a stylus and the installed Windows applications fit the small form factor perfectly.

The units coming to market in 2007 are basically just "proofs of concept," says a Gartner report on the UMPC market, but also adds that the technology for its successful implementation is "at least two years away."

Yes, the price is at an "ultra premium" level too.

On average, these tiny handheld PCs are in the price range of Rs 90,000 onwards, which means they are costlier than most high-end notebooks, and have comparable prices to any Tablet PC.

The form factor of the UMPC won't go away, but these devices are not meant to seduce the mass market. As expected, companies like Samsung, Sony, Fujitsu have redirected their attention towards the enterprise segment, for example field technicians who use Tablet PCs today would be the most likely to convert to these mini-PCs.

And if Intel has its way, then what is the mass market UMPC will eventually morph into much smaller and less powerful mobile Internet devices.

So, are UMPCs a fine example of getting the "right idea but wrong software"?

Perhaps only the consumers can decide. Meanwhile, if you have been dreaming about a cute little UMPC you can take on vacation instead of dragging that beefy notebook bag along, stop dreaming and go buy one!