12 May 2004

Technology laws

By Jim Pinto

Some technology laws actually are laws, defining how things operate. Ohm's Law relates voltage across a component to the product of its resistance and the current through it. Kirchoff's Laws deal with the sum of currents at any point in a circuit. These are the bedrock of electrical engineering.

But the popular laws, the ones that have become well known in the mainstream, are not really laws at all. They are mostly empirical, rules of thumb.

One example is Murphy's Law, which was first formulated in 1949 by Ed Murphy Jr., an aerospace engineer (not the comedian). After a botched test, he declared: "If there are two or more ways to do something, and one of those ways can result in a catastrophe, then someone will do it." Other less verbose, more colloquial, and more picturesque versions of Murphy's Law soon followed.

Here are the "laws" that define exponential advances of technology:

• Moore's Law: The number of transistors on a chip doubles annually.
• Rock's Law: The cost of semiconductor tools doubles every four years.
• Machrone's Law: The PC you want to buy will always be $5,000.
• Metcalfe's Law: A network's value grows in proportion to the square of the number of its users.
• Wirth's Law: Software execution is slowing faster than hardware is accelerating.
• Gilder's Law: Bandwidth grows at least three times faster than computer power.

Related links:

• IEEE Spectrum – The Five Commandments
• Murphy's Technology Laws

Behind the byline

Jim Pinto is an industry analyst and founder of San Diego–based Action Instruments. You can e-mail him at jim@jimpinto.com or view his writings at www.JimPinto.com. Read excerpts from his book, Automation Unplugged, at www.jimpinto.com/writings/unplugged.html.