Say the word "computer" and most people think of the machine on their desktop-a machine they love, hate, or a little of both. But that notion of computer is going the way of the Univac: less than one-tenth of one percent of all computing devices today have Intel inside, or run Windows. The computers that are having the biggest impact on our lives are the ones embedded in thousands of pieces of equipment that surround us every day. These are the devices that tell our antilock brakes when to unlock. They manage factory automation systems. They tell Tickle Me Elmo when he's being tickled. Soon they will allow our home appliances to diagnose their own malfunctions, and will even call and order their own replacement parts before they fail. These new computers will eventually make a stand-alone desktop system look as anachronistic as the vacuum tube.

But the little smart machines infiltrating our surroundings lack one thing that has made desktop computing so-well, so ordinary. The missing piece is a dominant operating system. Many contenders are already battling for dominance, and it looks as though the proponents of open-source software have a chance to vanquish Microsoft. In some respects, though, the future of "ubiquitous computing," in which computing power is found in the common objects that pervade our environment, depends less on the particular winner of this battle than on there simply being a winner at all: a common standard that everyone can agree on.

Too Many Choices

For most casual computer users, the phrase "operating system" conjures up a mental image of the Microsoft Windows screen. But an operating system is not just an arrangement of windows and icons; it is the layer of software that coordinates all actions of the computer. The operating system interprets our inputs and translates them into commands that the hardware understands. In very simple embedded devices, these commands can be etched into the hardware itself (that is the case with the heat sensors in digital thermometers, for instance). But the fastest growing segment of the embedded devices market includes personal digital assistants, Internet-capable cell phones, and other Internet access devices, all of which need operating systems nearly as sophisticated as the one running your desktop computer. Which operating system will dominate these newer devices is still up for grabs.