CALL ME a gardener, if you like, for I grow plants from seeds. But you won't find my plants in any garden. They grow in the fertile soil of my computer, and their stems and leaves are made from software. My plants are computer programs that write, adapt and repair themselves. No programmer is required.

They could hardly be more different from today's software. Conventional programs are designed to operate within strictly limited criteria, and these fragile monoliths crash at the slightest hint of an exceptional circumstance. Worse, modern software is fast becoming too complex for any one person to understand, and the bugs and glitches that are now accepted as an inescapable fact of life are the result. Most of us reluctantly put up with the frustration of rebooting our PCs and redoing the work lost in a software crash. But what if the faulty software is in the ...