Many people don't know it, but today's PCs--including the system you're using right now--contain elements that have hardly changed at all in the last 20 years. Yes, CPUs are faster, hard drives are bigger, and RAM banks are larger. But in many fundamental ways, your PC isn't very different from the PCs of two decades ago.

Think I'm exaggerating? Take a look at this almost-20-year-old image (left) scanned from the October 1984 issue of Byte magazine, which covered the rollout of the original IBM PC AT. If you've ever opened up your PC, the overall layout will instantly seem familiar, and you'll recognize many of the components. Note the power supply in the rear right corner, the floppies in the open bays on the right, the hard drive in the closed bay near the center, the system switches and speaker, and the card slots to the left. Experienced eyes will even pick out the BIOS chip, the battery backup for the BIOS, the RAM banks, the familiar-looking cables and electrical connectors, and more.

Although some of the system elements have been modified over time, almost everything in your PC is a direct lineal descendent of the IBM PC AT--a seminal design that still shapes PC architecture two decades later.

Stability--But Also Stagnation
In many ways, the PC's hardware consistency over time has been a good thing, a stabilizing force in the otherwise rapidly changing world of computing. It's been a huge positive for businesses and users because this consistency has made many peripherals completely interchangeable. For decades, we've been able to mix and match printers, keyboards, mice, monitors, scanners, modems, and more, largely without regard to the brand of PC.

Hardware standardization also has helped the bottom line by driving down prices: System and peripheral vendors have had a vast and uniform market from which to draw supplies, and to which to sell products, resulting in the commodity-level pricing that's behind today's amazingly low hardware costs. Overall, the PC AT's legacy has been an enormously positive one.

But it also has had a downside, principally in retarding innovation and slowing hardware advancements. The installed base--that is, the mass of existing, older, in-use hardware--acts like a giant speed brake on the computer industry because businesses and users are loath to give up older equipment that's still functional, even if newer designs would perform better or faster. As a result, new technologies tend to emerge piecemeal and more slowly than they would if hardware vendors could make a clean break with the past.

There's even a joke that made the rounds of the computing industry awhile ago: "Why was God able to create the universe in only seven days? Because he didn't have an installed base to deal with."

Despite this backward drag from the installed base, the Grail of many hardware engineers has long been a totally "legacy free" PC that can employ only fully modern, state-of-the-art, high-speed components and architectures. Such a PC would be faster, more compact, more reliable, and less expensive, as well as easier to manufacture and maintain.