When most people think about microprocessors, they think about the Athlon XPs, Pentiums, Celerons, and Opterons in desktops, notebooks, and servers. But those chips are just the tip of the iceberg. There are processors in your cell phone, your printer, your monitor, your PlayStation 2, your car, your toaster -- well, maybe if it's a very expensive toaster.

In terms of volume, sales revenue, and sheer impact on our lives, these special-purpose chips -- called embedded processors -- put conventional CPUs to shame; they're everywhere, they're multiplying, and they're getting very powerful. This week, we'll look at what makes embedded processors different from their PC cousins and how they got that way; in Part 2 of this story, we'll look at the future of the embedded processor industry and technology.

Multiple Multiprocessor Machines

To accurately reflect the market significance of the desktop and notebook chips usually discussed here, CPU Planet would have to be renamed something like CPU Island: According to the market watchers at World Semiconductor Trade Statistics, a nonprofit organization composed of semiconductor company representatives, PC processors comprise a paltry 2 percent of all processor sales.

In fact, the vast majority of 32-bit processors -- which include today's Pentiums and Athlon XPs -- sold each year are used in embedded systems, not personal computers. The average car sold today has at least a dozen microprocessors on board, with higher-end models having even more; some Mercedes and BMW models have over 60 apiece.

And while 32-bit and 64-bit chips may be chic, WSTS estimates that a quarter of a billion 8-bit microprocessors are still sold each month. At $6 to $18 apiece, these blue-collar chips are priced to move.

To be sure, these huge sales volumes don't translate directly into revenues. PC processors still generate about 30 percent of all semiconductor revenues; that's why Intel is a household name and ARM isn't. Even so, if you were to tour your house and check inside your TV, Game Boy, microwave, dishwasher, and so on, you could easily find 100 processors without counting your desktop (or its mouse, hard disk, or many other components).

The terminology used to describe embedded systems is a little different than that of PC industry. For instance, the desktop and laptop chips we're most familiar with are referred to as general-purpose processors or GPPs. Such chips are well-suited for performing a broad array of tasks, and must be compatible with common instruction sets. They also use too much power and run too hot to be practical in most embedded applications -- it might be possible to build a Pentium 4 into an automobile, but put it into a PDA or cell phone, and the device would melt in your hand.