By NANCY BETH JACKSON - New York Times

MAGINE this: Lieutenant Smith, a United States Army platoon leader at a base camp in Uzbekistan, is preparing for a three-day mission in Afghanistan. For four hours, he and his fellow officers have been going over maps and hundreds of details that must be nailed down. They retrieve the information they need from a new addition to their battle packs: hand-held computers.

In his tent, the lieutenant obtains a satellite photo of the target area from his hand-held device. Calling up a checklist from his digital field manual on the device, he makes sure that machine guns and mortars are ready for firing.

As his platoon embarks, he notes with a tap on the screen that each soldier has his rifle, grenades and his own hand-held computer, loaded with software including the Army Survival Manual and an English-Pashto translator. In the field the lieutenant uses the hand-held device to transmit digital photos and his exact position back to headquarters by satellite.

The chain of events may sound more like a video game than a battle plan. But applications like those may become routine in a war in which infrared satellite photography is being used to spot campfires in caves and global positioning system receivers identify a scout's precise location.

The hand-held computer is already in evidence in the military, which is using off- the-shelf software tested by the road warriors of the business world as well as applications designed specifically for the armed forces. While researchers work to meet battlefield challenges involving transmission, power sources and security, the makers of hand-held devices - most notably Palm and Handspring - are trying to move their military usefulness from niche to necessity.

"It is an extremely efficient way of replacing the cumbersome notebook, which was very traditional," said John Inkley, Palm's federal product manager, of the military transition from paper to hand-held devices. "But now it's gone way beyond that."

Describing the devices as "the electronic Swiss Army Knife," a company called Military Advantage (www.military.com) sells Palms with basic military applications and software bundles tailored for special operations forces, linguists, pilots, sailors, soldiers and medics. The site offers a free Afghanistan map, a basic Pashto-English lexicon and a chance to win a camouflage faceplate.

The Army Survival Manual, long available to civilians in paperback, can be loaded onto the Palm, as can a stack of Army field manuals. What's more, the digital information does not tear, get wet and muddied or blow away.

Charles Stibrany, a retired Army lieutenant colonel who helped construct the Lieutenant Smith situation for a reporter, saw his first Palm in 1997 in Sarajevo, in the hands of an American reservist who had been called up as part of a Bosnian peacekeeping mission. Borrowing it overnight, Mr. Stibrany became so intrigued with the possibilities of military applications that after retiring in 1999, he became a founder of Warrior Solutions, a developer of mobile military software in Boulder, Colo.

In March his company introduced software for the Palm operating system called Platoon Warrior that is intended to replace the bulky administrative books used by Army officers. The digital version allows users to pull together personnel information and contains checklists and memory aids "for routine operations in the field and in training."

Warrior Solutions makes the software available for downloading from the Web (www.warriorsolutions .com) or on CD-ROM for customers ranging from individual soldiers to battalions. An individual would pay $59.95 for a package; a battalion might pay about $5,700 for a package with 150,000 licenses. Palm and Military Advantage include it in bundled software.

Warrior Solutions is developing nine more programs related to the core module and plans to adapt the concept for the Marines, the Navy and the Air Force as well as for British, Canadian and Australian forces. No direct government financing or contract is involved.

All military branches have begun using hand-held computers, but the Navy has been the most aggressive in incorporating the technology. It began issuing Palms to its newly commissioned officers in 1999 as an investment in information technology in peacetime. The devices, which the Navy called Job Performance Aids, or J.P.A.'s, were introduced as "advanced administrative tools to enhance individual productivity and quality of work," according to an overview of the program on the Navy Web site.

More than 12,000 officers, including graduates of the Naval Academy and of the Naval Chaplains School in Newport, R.I., have received Palms in the last two years, most recently the Palm IIIxe (discontinued by Palm) and the Palm Vx, which would cost a civilian as much as $300.

The devices are meant to replace wheel books, used by generations of sailors from the ship's captain on down. A combination of to-do list, memory jogger, diary and record of lessons learned, wheel books ensured that all hands received and were accountable for orders and instructions. Still in use today, they are generally small spiral notepads that can be tucked in a pocket.

As more and more new officers started beaming messages on their hand-held computers, other sailors decided to buy their own. So far, the Navy has furnished 30,000 to 50,000 Palms, Mr. Inkley said. (Lt. Pauline Storum, a Navy spokeswoman at the Pentagon, said that while there was no specific Navy initiative to issue hand-held computers to every sailor, some individual units have supplied them out of general operating funds. "It's like buying a calculator or a fax machine," she said.)

The hand-held devices have been used for administrative duties ranging from transmitting orders of the day via the infrared ports installed around the ship to downloading e- mail. But programs tailored to specific military needs are also being developed. Two Navy aviators working on their own created software called PASS that allows landing signal officers to use hand-held devices to grade pilot landings on aircraft carriers and transfer the ratings immediately into the computer system rather than juggle paper, pens and flashlights on the flight deck.

Applications yet to be tested in the field suggest that hand-held devices could take on even more responsibility in wartime. Digital Sandbox (www.dsbox.com), a software developer whose name is a play on the sand tables of war games, has adapted its complex graphical programs for risk assessment and management to hand-held devices so that users can get quick access.

"Most people can't believe it's possible on the Palm, but we're not trying to put supercomputers on hand-helds," said Bryan Ware, lead designer and product manager at the company, based in Reston, Va. "Click a few buttons and you know the size of the problem - the most likely targets and the people most likely to do it." The full database of terrorism information could yield an instant assessment of security issues before an American ship pulls into a foreign harbor, he noted, recalling the terrorist attack on the destroyer Cole last year in Yemen.

Palm Elvis (for Enhanced Linked Virtual Information System), a system developed by Northrop Grumman Information Technology, would allow commanders to share information, including detailed maps, on the Palm, creating a common operational picture that could be updated from the field. Information is shared through infrared ports or transmitted back to a central server.

"Sometimes you are in somewhere where you are in danger and it would be good to know what information everyone else has about the situation," said David Tribble, a senior software engineer with Northrop Grumman.

But Mr. Tribble is the first to point out some of the technical problems that must be addressed before such communication takes place in the middle of battle. Just how much information can be displayed on a screen that fits in the hand? How will the devices be powered far from their ports? Can wireless Internet connections be extended far enough to allow communication on the battlefield? What kind of encryption will prevent the enemy from intercepting messages or gaining access to sensitive information if the device falls into the wrong hands?

Mr. Inkley of Palm contends that a hand-held computer can be made at least as secure as a desktop computer and considerably more secure than the traditional notebook that might be seized by the enemy. In his plan, plugging in the wrong password three or four times would destroy all of the data in the device.

After 24 years in the Army, Mr. Stibrany favors a simpler approach: before being captured, the soldier would drop his hand-held device and crush it to dust with his combat boot. That is far easier and faster, he says, than the old tactic of swallowing wads of paper.