Late for an appointment, you grab your "personal information appliance." Prompted by your uttering the words "cell phone," the small gadget awakens and instantly programs itself for a mobile phone call. Done with the call, you say "translator," and the device rewires itself to translate the latest business news from Tokyo. Issue the command "map," and it reconfigures itself again to take a GPS reading and display your location in real time.

One reason that this type of versatility is not possible today is that handheld gadgets are typically built around highly optimized specialty chips that do one thing really well. These chips are fast and relatively cheap, but their circuits are literally written in stone-or at least in silicon. A multipurpose gadget would have to have many specialized chips-a costly and clumsy solution. Alternately, you could use a general-purpose microprocessor, like the one in your PC, but that would be slow as well as expensive. For these reasons, chip designers are turning increasingly to reconfigurable hardware-integrated circuits where the architecture of the internal logic elements can be arranged and rearranged on the fly to fit particular applications.

Dozens of academic research groups and startup companies are pursuing the ideal of the reconfigurable computer (see table). One of the most promising approaches is a technology called "field-programmable gate arrays." The strategy is to build uniform arrays of thousands of logic elements, each of which can take on the personality of different, fundamental components of digital circuitry; the switches and wires can be reprogrammed to operate in any desired pattern, effectively rewiring a chip's circuitry on demand. A designer can download a new wiring pattern and store it in the chip's memory, where it can be easily accessed when needed. "This kind of reconfigurable logic is grabbing a larger and larger share of designs," says physicist Philip Kuekes of Hewlett-Packard Laboratories. "And it will get even bigger."

Basic reconfigurable circuits already play a huge role in telecommunications. For instance, relatively simple versions made by companies such as Xilinx and Altera are widely used for network routers and switches, enabling circuit designs to be easily updated electronically without replacing chips. In these early applications, however, the speed at which the chips reconfigure themselves is not critical.