‘DIGITAL NOMAD’ is a term that’s come to describe people whose primary place for using a computer is anywhere and everywhere as they move from meeting to meeting. You recognise them by this trait: as soon as they arrive, they are looking for a power socket to give their exhausted laptop a fresh ‘fix’ of electricity. The truly serious cases also suffer from anxiety if they are not wirelessly connected to the Internet. And there’s something of a paradox about being wirelessly Internetted — but forced to crash to earth at frequent intervals to recharge.

There are laptops which offer radically better battery performance: this was one of the aims, and indeed achievements, of the team who built the One Laptop Per Child XO machine. In the high street you can also find the ASUS EeePC, with WiFi 802.11n connectivity and up to eight hours of battery power, achieved in part by replacing the hard drive with a solid-state one (as in USB memory sticks).

Dell recently announced the Latitude E4300 laptop which is said to give up to 14 hours of continuous battery operation, yet runs Vista and has a proper hard disk. Since most laptops in this class manage only two to three hours on battery, you may well wonder by what feat of engineering this is achieved. The truth, as usual, is a little more nuanced.

The E3400 is a hybrid system:it’s as if it had a EeePC personality living inside the case alongside Vista. The ‘Latitude ON’ feature means users power up the machine in 5 seconds to a simplified environment providing a small range of communication facilities: wireless and wired networking, web browsing and Skype. In this mode, the E3400 works well as a ‘thin client’ machine for Net-centric operations. If the user needs to work in Windows apps, they can continue to boot up into Vista.

The secret is Splashtop, an innovative operating system solution from Chinese-American start-up company DeviceVM. Computers with Splashtop installed have a modified BIOS, and pressing the power button boots up a compact GNU/Linux OS. The startup screen gives immediate access to a Web browser (based on Firefox 2), photo browser, music player, Skype or chat – or a button to fire up the main heavy-lifting operation system, which can be Windows or Linux.

The ASUS EeePC is based around Splashtop, where it is rebranded as Express Gate. ASUSTek announced in May 2008 an intention to deploy Splashtop across a wide range of laptops, motherboards and desktop systems.

Details of the workings of the Dell Latitude E4300 and its little brother the E4200 are as yet unclear, but one report suggests that the Splashtop-based Latitude ON system uses a dedicated low-voltage processor. I would guess, therefore, that the estimates of 14 to 19 hours of battery operation are based on a mix of Splashtop-based net-centric operation and Vista-based orthodox working. Which, for many digital nomads, may accurately reflect the working day, though I personally would prefer to have at least a reasonable Open Source word-processor available within the Splashtop environment.