Gigahertz clock speeds. Nanometer processes. Forty years ago, they weren’t even science fiction yet. Rik Myslewski looks back at the first microprocessor to marvel at…

On November 15, pause to raise a pint to the 40th birthday of the original microprocessor. On that day in 1971, Electronic News carried an ad for the Intel 4004, the precursor of all processors, including the ones running your Mac and your iPhone -- and, for that matter, your car and your coffeemaker.

As marvelous as the 4004 was in its day, it was as crude as a stone axe when compared with its descendants. For example, the 4004 zipped along at a clock rate of 740kHz -- that’s kilohertz, or thousands of cycles per second for you newbies who’ve never seen a “k” in front of an “Hz.” Today, you can buy a 13-inch MacBook Pro with a 2.7GHz Intel Core i5. If you equate the 4004’s clock speed to, say, walking down the street, the Core i5 would scream along at about 36,500 miles per hour—about 11,000mph faster than a rocket escaping Earth’s gravitational pull.

The width of the 4004’s circuit lines is 10 microns. Today we measure such circuit features in nanometers; 10 microns equal 10,000 nanometers. That Core i5 has features manufactured at 32 nanometers—a 32nm process, as it’s called. If the Core i5’s process represents the length of...hmm...an unsharpened Ticonderoga #2 pencil, the 4004’s 10,000nm process would be as long as an 18-wheeler followed by a half-dozen 1962 Cadillac Eldorados and a Smart Car. Really. Trust me.

Then there are the 4004’s 2,300 transistors -- the switches inside a processor that process all those digital ones and zeros. The next version of Intel’s enterprise-class Itanium processor, codenamed “Poulson,” will have 3.1 billion transistors. To put that astonishing disparity in perspective, a pair of Intel 4004s contains just enough transistors to supply one for every citizen of Buffalo, Wyoming (“Where the Old West Comes Alive”). A pair of Poulsons will have one transistor for every living human being on Earth -- well, within a few hundred million, but you get my point.

The transistor population explosion allowed by process shrinkage has meant phenomenal growth in processor power -- not just how fast a processor computes, but what else it can do. Modern processors use those extra transistors to shut down unused parts of themselves to save energy, guess what an instruction stream is going to do next, paint your display with pixels, and much, much more. I can’t give you an exact metric for this one, but if an Intel 4004 is a garden slug, a Core i5 is Stephen Hawking.

The 4004 has 16 pins, but today’s Core i5 has 1155!

The benefits of process shrinkage, unfortunately, can’t go on forever. Intel’s chips, for example, are now at 32nm; the company has demonstrated 22nm “Ivy Bridge” processors, and it’s hard at work on 14nm. Chips will keep shrinking for some time—and the smaller a process gets, the more goodies you can fit onto a processor die -- but they’re going to hit a wall eventually. After all, a silicon atom is 0.27nm in diameter.

But well before that atom-size wall is hit, there’s the problem of etching a processor’s features onto a chip. The wavelengths of visible light are enormous compared with process sizes, and using that light to etch smaller and smaller features gets increasingly expensive due to the need for two or more etching masks. What’s worse, the long-awaited savior—a small-wavelength etching system called extreme ultraviolet lithography -- is running into serious problems with power needs and manufacturing speed.

So when you raise that pint to the Intel 4004 on November 15, do so knowing that the first 40 years were the easy ones.

The next 40 are going to be much more difficult -- and very, very interesting.

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Since the late 1980s, Rik Myslewski has paid his rent by keeping an eye on Apple. He was editor-in-chief of MacAddict from 2001 until its transformation into Mac|Life in early 2007, and is now a member of the snarkily sophisticated team at London’s The Register, which is “biting the hand that feeds IT” daily at www.theregister.co.uk.