Techno-File: Deconstructing the Latest and the Greatest

Reducing the power a computer needs would give us a portable worthy of its name

Most people require only a few things from a portable computer: It should be small enough to carry easily. It should allow you to perform basic tasks, such as writing, reviewing files, and retrieving E-mail. Its batteries should last a reasonable amount of time. The screen should be readable indoors and out. And it should wake up quickly when you turn it on.

But no portable computer today meets those basic requirements. Today's models are essentially desktop computers shoehorned into small boxes--power eaters with too much muscle.

Interestingly, the first widely distributed laptop, the Tandy Model 100, introduced in 1983, was arguably a better portable computer than anything currently on the market. This four-pound machine ran for 15 hours on four AA batteries, had a full-size keyboard, powered up instantly, and saved all information automatically.

Battery technology is partly to blame. In the past 10 years, battery capacity has hardly changed at all, while the capacity of components such as memory and storage have increased one- to two-thousandfold. And despite several improvements in battery chemistry, no breakthrough in capacity appears likely in the near future.

A partial solution is to make it easier to recharge batteries. Duracell has attempted to persuade computer manufacturers to standardize a battery shape so that you could, say, swap a depleted battery for a fully charged one in the airport. But computer makers have refused because they make so much money on their proprietary battery shapes.

A solution from the airlines promises some relief. A few airlines, led by Delta, have installed EmPower connectors, developed by PRIMEX Aerospace Co., at first-class and business-class seats. The connector, located near the headphone plug, supplies 15-volt power, up to 80 watts, and acts like a small version of a car's cigarette-lighter connector. About 50 planes now come equipped with EmPower connectors, and PRIMEX expects to install them in 1,000 more by the end of 1998.

We've also got to be smarter about using the power we have. That means manufacturers must figure out the optimal configuration of operating system, software, speed, memory, and drives. The first two must be rewritten in simpler versions for portables yet still be file-compatible with PCs. Processor speeds should be kept as low as practical because every time the speed is doubled, the power consumption is quadrupled. Today's laptops usually have 16 MB or 32 MB of memory in addition to the hard drive. But with that much memory you don't really need a hard drive, which uses a lot of power.

Amazingly, you can't get a laptop with a full-size keyboard today that doesn't have a color screen, even though a color screen hogs power and goes black outdoors. But one promising color-screen technology is now in development, based on a type of liquid crystal display (LCD) that uses so-called guest-host chemistry. Guest-host LCDs provide two to four pale colors. And their power requirements are low, partly because they don't need backlighting.

Within three years we can expect a three- pound true portable with a readable screen and a full-size keyboard that runs for perhaps 10 hours on batteries. Once it's here, you may wonder why you need a desktop PC at all.

Cary Lu is writing Understanding Bandwidth , to be published this fall by Microsoft Press.