Designers of portable computers for US military personnel are giving soldiers more options to take into the field, including tablet PCs and fully functional notebook devices so small that they can fit into someone's pocket. But one thing the vendors aren't giving users is Windows Vista.

For instance, defense contractor General Dynamics doesn't sell retail PCs, but it offers a line of laptops aimed at the military, police officers and other workers whose occupations require the use of PCs in extreme environments.

Last June, the company's Itronix unit introduced what it claimed is the smallest ruggedized notebook PC, the GoBook MR-1. General Dynamics claims that the MR-1 is small enough that military users could carry the PC in a pocket on their combat fatigues. It has a 5.6-inch display, a 1.2-GHz Intel Core Solo U1400 processor, a variety of wireless connectivity options and GPS capabilities. Pricing begins at about US$4,450.

Jan O'Hara, vice president of federal markets at General Dynamics, said at the FOSE 2008 Conference and Exposition, in the US, that the US Air Force helped develop the MR-1 and is using the system to call in bomb strikes.

The MR-1 comes with Windows XP installed on it, and it was hard to find Windows Vista among the systems that vendors were displaying at the FOSE show. The military, in particular, still relies on XP. O'Hara said that because of application-porting issues, it could be two years before federal users of products such as the MR-1 move to Vista. "Federal is all XP," she said.

Panasonic Corporation of North America, which makes ruggedized Toughbook laptops, had one machine loaded with Vista at FOSE. But Jan Ruderman, senior director of the government sector at Panasonic Computer Solutions, said there's no real demand for that operating system. "Right now, customers are saying they don't want it anytime soon," he said.

Ruderman said there are government customers who still use even older versions of Windows than XP, such as Windows 2000. For those customers, all that Panasonic can provide now are drivers, not the operating system itself.

Ruggedized PCs vary in size and shape, but they're all designed to meet the military's MIL-STD 810 technical specifications, which set standards for durability. The systems generally don't have air vents and are designed to be used in extreme conditions such as tropical rainstorms, snow, desert sandstorms and intensely bright light.

A key feature is their ability to survive impacts. If you leave one of the PCs on the roof of your car and drive off, there's a chance it may still be working after you hear it bounce in your driveway. That requires the ability to survive, at a minimum, a three-foot drop.

For instance, Getac equips its systems with an accelerometer that can detect if a fall is occurring and then park the disk drive head into a safe position. Joe Chernof, a technical sales manager at Getac, said the accelerometer technology was adapted from products in the aerospace industry. Getac recently added a tablet PC called the E100 to its collection of ruggedized systems.

Scott Nettleton, president of Ridgeline Technology, a reseller of military-grade laptops, said the purchasing options are growing for buyers. "In the last three years, we've started to see more competition for ruggedized products," he said. Prices generally range from US$2,400 to $3,700 for the ruggedized systems, according to Nettleton, who said users are pushing vendors for lighter and more secure products.