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.
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.
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.
- Fred Langa
The IBM PC shipped in 1981 -- over twenty years ago. The PC offered various expansion capabilities, including a parallel port, a pair of serial ports (on a separate card), and a keyboard port. It also supported a 5.25" 160KB single-sided floppy disk. The 8-bit PC/XT bus slots were expanded to 16-bit ISA slots in the PC/AT in late 1984. Later, IBM shipped the PS/2, whose enduring legacy in the PC universe today is a pair of compact connectors for the keyboard and mouse, and the 3.5" 1.44MB floppy drive.
Recently, I dug out an old Northgate Omnikey keyboard that's been gathering dust in my storage area. It's at least ten years old. I plugged in a PC-to-PS/2 keyboard adapter. It still works. This type of backwards compatibility has been the great strength of the PC over the years, but it's rapidly becoming an Achilles heel. Various factors have kept these anachronisms in place, such as corporate IT shops that need to support parallel and serial ports, or users with a pile of floppies that contain valuable data. We've even seen an ISA slots in a few new systems. And no doubt the Super I/O chip is still using ISA signaling to support legacy I/O.
So it's no surprise that a company like Apple Computers can push interesting new technologies into their hardware and software more quickly than PC manufacturers. But the buzz over the "legacy free" PCs is starting to heat up. It began several years ago, with both Intel and Microsoft encouraging PC makers to move away from legacy connections. Back then, the pleas fell mostly on deaf ears, but it's beginning to look like the industry is ready. Dell is starting to ship USB keyboards, Gateway will pay you to delete the floppy drive, and at least one component company -- ABIT -- is shipping a line of "legacy-free" motherboards.
What do we mean by "legacy" here? Specifically, we're talking about a set of I/O options that have been part of the PC architecture for a long, long time.
If you look at "legacy-free" meaning a system that eliminates the entire kit and caboodle of this table, then we're still several years out. PCI and AGP will be around for at least two more years before PCI Express surfaces in force. Even then, don't expect systems to get rid of PCI slots anytime soon. Parallel IDE hard drives will probably be around for a couple more years, but will gradually give way to Serial ATA. Similarly, parallel SCSI will yield to serial-attached SCSI.
Actually, we shouldn't forget that the VGA port is also a legacy standard. In fact, VGA hardware is the only remaining piece of hardware that interacts directly with Windows. There is a move afoot to eliminate VGA, called the Universal Graphics Adapter or "UGA". The firmware-based UGA functionality will be accessible via a UGA driver built into the next version of Windows, codenamed Longhorn. If the graphics chip makers consider removing VGA at that time, we could be completely legacy-free.
- Loyd Case
Did you know that the latest Intel Macs are actually "Legacy Free PCs"? In case you do not believe me, do a Google search for any Intel Mac's hardware specifications.
Why a Legacy Free PC?
Three words... simplicity, stability and evolution.
How can we define Legacy Free PCs now? Here is an overview:
Must Not Have
Floppy Disk Controller
Indeed, as system designers are freed of the constraints of the past, we'll likely see radical PC designs that will not only be faster, smaller, and better than today's designs, but that will make the traditional beige-box PC seem positively antiquated. And I, for one, can't wait!