Network: In a cleft stick with my laptop: You can take a computer anywhere - but beware, warns Raymond Whitaker

PERHAPS it was in Afghanistan, where the local electricity supply melted the casing of my laptop and blew the screen backlighting, that I began to appreciate some of the problems of taking computers to the rougher parts of the world.

These are countries at the bottom of the graph for computer friendliness. When computer manufacturers boast of portability and ease of use anywhere in the world, they picture business types moving from one industrialised nation to another, not places where the ox cart is standard technology.

I was not even thinking of trying to connect my computer to Kabul's telephone system when I had finished my piece: I was going to have to retype on a telex machine. But journalists have become addicted to keyboards and screens because the ease of shifting text about has fundamentally changed the way they write. Instead of having to order their thoughts before they start, they can begin almost at random, experimenting and refining until a shape emerges. It becomes almost impossible to revert to old technology, as I discovered when I had another crippling encounter with the Third World, this time in Cambodia.

A 'spike' in the local power supply came just as the hard disk was spinning in my Toshiba, jamming it irretrievably. The rest of my reports had to be written with nothing more sophisticated than pen and paper, and it was like learning to speak again after a stroke.

Why had I been so stupid as to plug into what passes for the national grid in either country? The answer is that while satellites can make it possible to bypass local telephone systems, advances in power technology have not been so rapid.

The first machine to persuade journalists that it might be worth taking off the beaten track was the Tandy 200. It was light, the word-processing and communications software were built in (no disk drive to go wrong) and, best of all, it ran on four AA batteries. Even though you could not obtain decent batteries in many developing countries, and had to lug them out with you, it was better than risking electrocution or irreparable computer failure.

But the many disadvantages of the Tandy 200 included slow operation, a liquid crystal screen that was hard to see, and minimal storage capacity. Articles which had not yet been used by the paper - and could therefore still go astray - had to be deleted to make room for the next one.

It was tempting, then, to contemplate the next generation of portables. They had virtually limitless memory compared with the Tandy, their backlit screens were easy on the eye and they ran much faster. But they were power-hungry: they had hard disks and built-in fans to keep the works cool, not to mention fancy software such as Windows. They needed heavy nickel-cadmium battery packs, but could not do without mains power for long.

If you avoided using the hard disk too often, and switched off the machine while you thought, a battery pack could last four hours. That might seem plenty of time to finish one's work, but it was never that simple.

Unless nickel-cadmium batteries are charged up fully, then drained fully, they lose their ability to retain any charge at all. Short of carrying a battery charger and spare packs, the peripatetic computer-user sooner or later has to use the mains to power the machine in the middle of a work session, with the kind of consequences described above.

Enter the next generation of portables, which attempt to return to the virtues of the Tandy 200 while retaining the advantages of its successors. My Hewlett Packard Omnibook 300 weighs 3lb, eschews backlighting and uses 'flash card' technology, which requires scarcely any power, instead of hard or floppy disks. The small nickel-metal-hydride battery pack can be partially recharged without ill effects and can keep running for five hours. And it can run on four AA batteries as well.