In contrast to the plethora of ruggedised handheld computers now available, the choice of ruggedised notebooks is much more restricted. Still, there are a few manufacturers prepared to meet the challenge of making sensitive electronics indestructible. Sharon Clancy reports

Despite the transformation of ruggedised handheld computers from simple data capture devices into sophisticated mobile computers, often able to run a wide variety of applications, there are some activities which simply demand a notebook computer.

It's obvious why. Some mobile workers have requirements too complicated for handhelds. They might need to view a complicated schematic on a reasonable-sized screen, or simply to enter complicated data or large amounts of text. Some need to work offline for considerable periods of time, using major applications held locally on the device rather than remotely on a server.

However, for some operations standard notebooks, even those aimed at professionals, are simply not up to the job. Although users may not intentionally abuse them, they may not always treat them with tender loving care either.

One answer is a semi-rugged notebook - similar to business and consumer models, but somewhat more robust. But for operations where the notebook is used out of doors or on industrial sites, or where the risk of its being accidentally dropped is higher, it also needs to be resistant to heat, cold, dirt and shock. In these situations toughness is the name of the game.

Historically, ruggedised notebooks were first developed to meet the demands of the military, especially the US military. Handily, that makes it relatively easy to compare specifications; manufacturers often cite their ability to pass the US Army's military specification tests, MIL-SPEC, so you just have to check which model conforms to what standards.

However, there are different types of test for each category, so you need to check that you are comparing apples with apples. The MIL-STD-810F test for water ingress, for example, can be a drip check, a water immersion test or a spray test. Makers also quote IP54 and IP65 environmental standards for water and dust resistance.

It can also be worthwhile asking how the notebook actually performed, not whether it simply passed. One key MIL-STD test for shock-resistance, for example, involves twenty-six one-metre drops on to concrete. Manufacturers are allowed to use up to five notebooks to achieve that result. Itronix, however, not only passed the test with a single computer from its GoBookMax range; it also reports that the model survived fifty-four drops, on all sides, open and closed, and with the computer switched on. Hard to imagine, isn't it? It is dust-resistant sufficiently to withstand a typhoon blowing, and the waterproofing standards are high enough for the notebook to be washed down with a hose.

Shock-absorbing mounts are the usual method of protecting the hard drive and screen from vibration and hard knocks, plus flexible connections between disk drives and system boards.

Tests for ruggedness certainly require faith in your machine. For instance, consider the testing Panasonic carries out on its ToughBooks to check data loss and operation in extreme conditions. The computers are turned on and heated to 60 deg C, switched off, heated some more to 71 deg and turned on again to check they will boot up. For cold conditions, the test is down to minus 29 deg switched on and to an even chillier minus 51 deg C switched off.

Panasonic went further: the ToughBooks then went through three cycles of high temperatures (96 deg C ) to low (minus 51 deg C), just to prove it wasn't a fluke.

All the ruggedised notebooks come with anti-glare screens, so can be used in bright daylight. ItroniX GoBookMax notebooks also include a full-sized NiteVue QWERTY keyboard with phosphorescent white plastic keys that make the black letters easily visible at night or in poor light conditions. For less demanding environments, the Itronix range includes GoBook and GoBook II. All have Itronix's CRMA technology, which allows remote upgrades to notebooks as field service IT infrastructure changes.

Panasonic ToughBooks have spill-resistant keyboards and touchpads and slots, and terminals have hinged covers and dust- and water-resistant seals. Even the LCD panel has a sealed protective overlay. The latest model, the CF-29, is one of the first to incorporate Intel's Centrino mobile specification, and comes with WLAN and modem as standard.

Itronix and Panasonic are probably the best-known makers in the ruggedised computer market, but there are other contenders. UK manufacturer Terralogic, for example, is a specialist in rugged mobile computers, supplying military organisations, government agencies and companies working in inhospitable places. There is a range of waterproof computers, but Terralogic is best known for its rugged Toughnote notebooks, which have been used in conditions ranging from polar ice caps to cross-Sahara expeditions.

Meanwhile, Canadian manufacturer Xplore Technologies has made a speciality of ruggedised Tablet PCs (again meeting MIL-STD-810F standards), and has lately signed an agreement under which its range will be sold in Britain through Psion Teklogix (more on page 28).

The arrival of GPRS has made notebooks a more versatile and attractive proposition than in the past. They have been transformed from tools with restricted communications links (often reliant on a land line at the end of the day's work) to multi-mode fully-connected devices. Modem, GPRS, WLAN and WWAN capabilities are often included as standard.

Some users believe notebooks evolve too quickly to make the extra investment in ruggedised computers worthwhile; they don't want to feel left behind with tough but potentially outdated technology. However, a standard notebook in an unsuitable environment is far more likely to become damaged, sometimes irretrievably so, long before it becomes obsolete. If your mobile workers need a notebook to do their jobs, any saving in buying a standard computer would soon be eaten up by lost productivity. It really is a question of getting what you pay for.