Happy birthday, x86! An industry standard turns 30

Intel's x86 microprocessor architecture has dominated large swaths of computing for three decades. Here's why.

The 386 was followed by the 486 in 1989. Finding that it couldn't trademark numbers, however, Intel broke from its earlier naming convention in 1993, when it named its fifth-generation processor the Pentium rather than the 586. Numerous generations of chips have carried on the Pentium brand (e.g., Pentium Pro, Pentium II and Pentium D), and Intel has since added the low-end Celeron and the high-end Core 2 brands to its x86 offerings.

Despite the name changes -- not to mention design improvements that led to exponential increases in speed, power and efficiency -- all of these chips are based on the x86 instruction set that began with the 8086 and continues to expand today.

Ingredients in a recipe for success

Why has the x86 been so successful for so long, beating back and in some cases completely vanquishing competing microprocessor architectures? For starters, the x86 came along at just the right time. By 1978, computing had been migrating from huge, expensive mainframes to smaller, cheaper minicomputers for several years. The desktop was the logical next frontier.

Moreover, the x86 demonstrated a property that had been predicted in 1965 by Gordon Moore, who would one day become Intel's chairman and CEO. Moore said, in essence, that microprocessors would double in performance every two years at no increase in cost. His prediction, later dubbed Moore's Law, proved to be correct, and the x86 went on to dominate large swaths of computing, from the data center to the workplaces and homes of end users.

And the 8086 and its successors continued to cement the relationship between two early giants of the desktop computer industry. Bill Gates and Paul Allen had tried but failed to develop their Basic programming language for the wimpy 8008 processor in 1972. But they made it work on the more powerful 8080 that they soldered into the Altair microcomputer in 1975.

That marked the beginning of a de facto partnership between Intel and Microsoft that would create a gargantuan base of software that continues to drive the industry today. Of all the factors that have led to the success of the x86 architecture, probably none is so important as that software inventory -- and no example better demonstrates this fact than the RISC processor scare.

The RISC risk

In the late 1980s and early 1990s, a serious threat to the x86 arose in the form of reduced instruction set computing (RISC) processors such as the Sun Sparc, the IBM/Apple/Motorola PowerPC and the MIPS processors. The idea was that a processor could be made to run blindingly fast if it worked on very simple instructions, with one instruction executed each clock cycle, rather than with the elaborate, multicycle instructions used in complex instruction set computing (CISC) processors like the x86.

Pundits, the press and Intel competitors widely predicted the demise of CISC at the time. "It was a difficult time for us," Gelsinger acknowledges. Indeed, Intel rushed to develop its own RISC workstation processor, the i860. But neither the 860 nor any other RISC processor came close to dislodging the hegemony of the x86.

Here's why, according to Gelsinger, who was the lead architect for the 80486 processor: "The day before the 486 was announced [April 10, 1989], there was already billions of dollars of software waiting to run on the chip. Even though the [x86 CISC] architecture was a little bit slower, by the time you could develop software for the RISC machine, we could make the [x86] machine that much faster. We had an overwhelming economic advantage because we had so much of an installed base and so many people developing. The RISC machine could never catch up."

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