If You have been hankering for a portable, full-function Windows PC to take along to the field, but are put off by the bulk of a laptop, a relatively new class of computers — the ultra-mobile PC — may fit the bill.

Unless you are a computer geek, you may not have heard of ultra-mobile PCs, or UMPCs for short. The brainchild of Microsoft, Intel and several computer manufacturers, the concept was rolled out in 2006. The companies conceived of a small (no more than 8 in. diagonally) touch-screen computer weighing less than 2 lbs. that would bridge the gap between handheld Windows CE computers and laptops. Envision an oversized BlackBerry or PDA with a small keyboard, but with the processing power of a PC.

UMPCs emphasize communications technologies to keep users connected via e-mail and the Internet. All are Wi-Fi ready, and most offer standard or optional GPS and broadband cards.

In general, consumer reaction to these computers has been ho-hum. But a niche version of the UMPC — the rugged UMPC — has attracted attention from industries, like farming, that need a mobile computer to operate in tough environments.

When married to a daylight-readable screen, a shockproof case and other innards designed to withstand tough conditions, the UMPC can be an excellent choice for a field computer.

“It is a niche product for people who want more than a handheld computer or PDA can give them, but don't want something that is too large,” says Conrad Blickenstorfer, editor and publisher of several Web sites devoted to specialized computers and electronics, including www.ruggedpcreview.com. “I am fairly optimistic that the UMPC concept will prevail in the rugged market. But it will not be mainstream.”

The rugged UMPCs also may not be ideal for all types of fieldwork. For example, if your goal is to work on spreadsheets and other mainstream PC applications during spare moments, a UMPC may not be the computer for you.

Although screens on rugged UMPCs are bright, they are small, so eyestrain is likely under heavy use. And inputting data is challenging with the tiny keyboards on these devices.

“Any time you talk about a UMPC you have compromises,” Blickenstorfer notes. “Screens are small. Keyboards are tiny, somewhere between a PDA and a real PC. How much inconvenience are you going to put up with for mobility?”

To offset that challenge, many UMPCs have ports and/or docking stations that allow users to hook to larger monitors and full-sized keyboards for use in the office.

SwitchBack

The SwitchBack (see photo on page 35) has a tablet shape, with overall dimensions of 7.5 × 5.5 × 2 in., and weighs 3 lbs. It is powered by a 1.0-gigahertz (GHz) Intel Celeron M processor, up to 2 GB of RAM, removable 80- or 120-GB hard drives (or 32- or 64-GB solid-state drives) and a hot-swappable lithium-ion battery offering 2 to 4 hours of run time. It meets the military's MIL-STD-810F specifications for ruggedness and IP-67 (ingress protection) for operating in conditions of extreme shock, vibration, temperature and immersion.

A base model SwitchBack, available directly from Roper Mobile Technologies, sells for about $4,500. Call 480/705-4200, visit www.ropermobile.com or www.freeproductinfo.net/fin, or circle 106.

GoBook MR-1

With its clamshell design, the GoBook MR-1 from General Dynamics Intronix is the most traditional looking of the rugged UMPCs. The clam opens to a 5.6-in. daylight-readable screen at the top, 76-key sealed keyboard at the bottom. When closed, it measures 4.3 × 6 in., is 1.6 in. thick and weighs 2 lbs.

It is powered by a 1.2-GHz Intel Core Solo processor and is available with up to 1 GB of RAM. A 40-GB hard drive is standard. An 80-GB drive is optional. It meets or exceeds the military's MIL-STD 810F standard for temperature and drop, as well as vibration testing. The unit is also IP-54 rated for dust and humidity, making it suitable for use in harsh and unpredictable environments. It has a projected battery life of 3 hours.

When introduced in May 2007, it had a retail price of $4,450. A base model is available for $4,200 from an Internet vendor linked from the GD-Intronix Web site. Call 800/441-1309, visit www.gd-itronix.com or www.freeproductinfo.net/fin, or circle 107.

Toughbook CF-U1

The Toughbook CF-U1 from Panasonic is 7 in. wide, 6 in. deep and 2 in. high and weighs 2.3 lbs. It has a tablet design, with a 5.6-in. sunlight-viewable touch screen and a mini 61-key keyboard.

It is powered by Intel's low-energy, 1.33-GHz Atom processor and comes with 1 GB of memory. The base version includes a 16-GB, removable solid-state drive. Dual hot-swappable batteries provide up to 9 hours of operation.

Panasonic says the CF-U1 is rugged enough to survive a 4-ft. drop. Its fan-less design enables a sealed, all-weather enclosure. The CF-U1 has integrated Wi-Fi and Bluetooth connectivity and USB and SD card slots.

A base model Toughbook CF-U1 retails for $2,499. Call 800/211-7262, visit www.panasonic.com or www.freeproduct info.net/fin, or circle 108.

Q1 Ultra Premium

The Q1 Ultra Premium UMPC has a 7-in. touch screen, which splits the keypad. About 5 in. high, 9 in. wide and 1 in. thick, it weighs 1.9 lbs.

Powered by a 1.33-GHz ultralow-voltage Intel Core Solo processor, it has 2 GB of RAM, an 80-GB hard drive and a lithium ion battery providing 7.5 hours of operation. Standard features include an integrated Wi-Fi and Bluetooth, a 300-pixel Webcam and a 1.3-megapixel camera.

Price is $1,399. Call 800/726-7864, visit www.samsung.com/us or www.freeproductinfo.net/fin, or circle 109.

OQO Model 2

The Model 2 UMPC from OQO comes in three versions that start at $1,300 and top out at $3,000. The company claims that its UMPC, which is just over 3 in. high, about 5.6 in. wide and 1 in. thick, is the world's smallest Windows-capable PC. It weighs 1 lb.

The 5-in. touch display slides forward to reveal a 58-key thumb board and track stick. The magnesium case has been engineered with nine integral antennas to support wireless communications technologies. Estimated run time with a standard battery is 3 hours.

The high-end Model 2 is powered by a 1.6-GHz VIA processor, a shock-mounted hard drive of up to 120 GB and 1 GB of RAM. Call 877/676-6688, visit www.oqo.com or www.freeproductinfo.net/fin, or circle 110.