From the introduction of Intel's 4004 chip in 1971 to today's quad-core desktop chips with four processing engines, the evolution of the commercial microprocessor has come a long way in just 35 years.

On Monday evening, the Computer History Museum in Mountain View, Calif., celebrated the 35th anniversary of the 4004, the world's first silicon-based microprocessor, by inviting the Intel team responsible for its development to speak to museum members and the public.

As it turns out, computer enthusiasts (as well as Intel) have a Japanese calculator company, Busicom, to thank for the push forward to develop the commercial microprocessor.

• Click here for FOXNews.com's Patents and Innovation Center.

In 1969, Nippon Calculating Machine Corporation commissioned Intel to design 12 custom chips for a new calculator it was developing, the Busicom 141-PF.

Instead of creating a dozen chips specifically designed for the calculator, Ted Hoff, Federico Faggin and Stan Mazor proposed an alternative design: a family of four chips (the MCS-4), including one that could be programmed for use in a variety of products.

Thus, the 4004 was born.

Included was a supporting read-only memory (ROM) chip for the custom applications programs, a central processing unit (CPU) chip, a random access memory (RAM) chip for processing data, and a shift register chip for input/output (I/O) port.

Intel (INTC) managed to deliver the four chips to Busicom by March of 1971 and Busicom eventually sold 100,000 141-PF printing calculators, according to Hoff.

In large part, it was the last-minute rush to meet Busicom's deadline that helped Intel edge out Texas Instruments (TXN) — a company that was also close to completing its own microprocessor in 1971 — and marked an important (and lucrative) change for a company whose previous focus was solely on making memory chips.

"The design was six months behind schedule and therefore I had the honor of being six months late the first day I started at Intel," Faggin told the audience.

"Futhermore, Intel had no expertise in, no methodology for, and no infrastructure for random logic chip design," Faggin added. "We had to do everything ourselves, from logic and circuit design, to layout and ruby cutting, to mask-making and wafer fabrication."

"It's hard to think of the world without the microprocessor," said Hoff, "but once the 4004 was developed, we actually had to do a great deal to convince Intel that this was a good idea with practical applications."

Measuring 1/8 inches by 1/6 inches, the 4004 microprocessor delivered about the same computing power as the first electronic computer, the ENIAC, according to Hoff. The only difference was that ENIAC used 18,000 vacuum tubes and filled an entire room.

While today's microprocessors are produced on 12-inch or 300-mm wafers, the Intel 4004 microprocessor was produced on 2-inch wafers. Composed of five layers, the Intel 4004 still holds the distinction today of being one of the smallest microprocessor designs that ever went into commercial production.

Today's Intel Core2 Duo processors contain over 291 million transistors, about 100,000 times the number of transistors than were in the 4004.

Starting on Nov. 15, the Intel Museum will be launching its own exhibit on the 4004.

Copyright © 2006 Ziff Davis Media Inc. All Rights Reserved. Reproduction in whole or in part in any form or medium without express written permission of Ziff Davis Media Inc. is prohibited.