Coifman's software would only cost a fraction as much. 7.6 CHIP IMPLANTS Perhaps the final level of pervasive computing is human chip implants, which can be used to identify people or to track their movements. An implanted chip module could also give users the power to communicate and process infor- mation without relying on external devices. That will be good news for anyone who has misplaced a mobile phone, PDA, or laptop computer. Some people favor chip implants because it would simplify life by elimi- nating the need to carry driver's licenses, passports, and other kinds of forge- able identification. Civil libertarians, on the other hand, shudder at the thought of giving governments and corporations the power to track and categorize people. Whether implantable chips ever become a widely used means of identification depends less on technology-for the basic technology is already here-and more on the attitudes of people and their governments. 7.6.1 Getting Under Your Skin Global Positioning System (GPS) technology is popping up in a variety of products from PDAs to handheld navigation units to children's bracelets. But why lug around an external unit when you can have a GPS chip implanted inside your body? Applied Digital Solutions is working on just such a tech- CHIP IMPLANTS nology. The Palm Beach, Florida-based company has developed and recently concluded preliminary testing of a subdermal (under-the-skin) GPS personal location device (PLD). A PLD could support various applications, including tracking missing chil- dren, hikers, or kidnapping victims. More ominously, repressive governments could use the technology to track the movements of political dissidents and other troublesome people. The GPS chip includes a wireless receiver, transmitter, and antenna. Although satellite technology is used to determine a subject's location to within a few feet, the device must connect to a mobile phone network in order to relay information to outside parties. The PLD prototype's dimensions are 2.5 inches in diameter by 