I bought a new laptop yesterday.

And to my surprise I violated my Iron Law.

Dana's Iron Law of Laptops holds that an ounce on the desk is a pound in my hands.

My favorite laptop of all time was a 2-pound Sinclair ZX-81. It had a tiny screen (nearly non-existent) but it had a pliant membrane keyboard that let me write and send stories from a beach. I haven't seen anything so light, rugged and useful since.

Instead, laptops have been desktop analogs. When desktop power increased, so did that of laptops, and they became no lighter in the process. Even today most laptops on the market weigh 7-8 pounds.

So why did I get one?

• To get weight down manufacturers sacrifice keyboard quality. Fujitsu has a very nice 4-pounder, but the keys are very close together, and their tactile feel is poor compared with the same company's 8-pounder.
• Small laptops cost more money. The Fujitsu 4-pounder cost twice as much as equally-powerful 8-pounders.
• Laptop battery life is still abysmal, and most laptop users must still lug power cords behind them.
• A rugged laptop is also a heavy laptop. Dropping weight means an increased risk your laptop will stop working.

These compromises result from an artifact in chip design.

As circuit lines get closer together, chips get hotter. Intel responded last year by sacrificing speed for lower-power designs. One product is the M Chip powering the Fujitsu. But new costs money at first, and M Chip designs at popular prices are still at least a year away.

This still leaves the problem of bad keyboards. I don't know why no one has brought back that old Sinclair membrane design, in which a one-piece rubberized keypad is placed over a set of electronics, rendering them waterproof. All laptops today are very vulnerable to sand and salt. They're vulnerable, period.

The bottom line is I violated my Iron Law and picked up a reconditioned Presario R3000 for $750. When something better comes along this can go with my daughter to college.

I'm just surprised nothing better is available in 2005.