In an industry known for its planned obsolescence, few technologies have lasted three decades and continue to grow more powerful with each passing year. The few that are out there, like DRAM and Motorola's 68000 processor, are chip-based.

Add to that list the x86 architecture, which stands alone in the broader computer market now that Sun Microsystems' Sparc processor is on life support. There have been many attempts to knock off the x86, from Sparc to HP's PA-RISC to SGI's MIPS to DEC's Alpha. But resistance proved futile; many PA-RISC and Alpha engineers now work for Intel on the Itanium, which was also supposed to retire x86. Intel's only real competitor any more is another x86 company, AMD (NYSE: AMD).

Meanwhile, the x86 keeps humming along; it now powers everything from the fastest supercomputers on Earth down to handheld music and Internet devices and PCs and servers in between. Soon it will be in phones. Name another architecture that spans eight-core processors to smart phones.

Still, Intel (NASDAQ: INTC) itself has tried to put the x86 out to pasture more than once and couldn't do it. There was the iAPX-432 in the 1980s, the i860 in the early 1990s and then Itanium.

"If you were going to bet on an architecture that would be around in 20 years, which would you pick? I could think of only two, the IBM mainframe, which has been around 45 years and counting, and x86. All these other guys came and went," said Martin Reynolds, research vice president and fellow with Gartner.

The reason, he argues, is that x86 as an instruction set is mature and fully baked. Anything that comes along is in addition to what is already there, but there is no changing of the fundamentals. This helps maintain backwards compatibility that would in theory allow Windows 95 to run on a Core 2 Quad machine and have more driver problems than instruction problems.

"When we were debating multi-core internally, all the focus seemed to be on rewriting these apps and I said to management, 'stop. What you should assume is no apps will be rewritten. They simply have to run.' What we're all about is making sure the new apps take advantage of this capability without a loss of compatibility," said Intel CTO Justin Rattner.

Preserving that legacy was Intel's smartest move, argued the analysts. "They are changing x86 architecture, but when they do it's always additive and always backwards compatible," Reynolds told InternetNews.com. "Every x86 has a different implementation. It may have a different microarchitecture but it has the same instruction set."

Because x86 is a cumulative technology that keeps the old along with adding new, this allows it to keep the old while adding new technologies. It has created a scenario where x86 can literally go on forever, adding enhancements while supporting its legacy, until something knocks it off the perch. Many have tried.

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