It's the Law!

Moore's law, Brooks' law, Linus' law, Murphy's law.


When IT professionals have looked at the possibilities of computing, a number of observations have been made because their underlying truths were so obvious, painful or accurate. This special QuickStudy presents a few of these better-known "laws." In the companion story, we group many other laws based on the area of computing or type of user they affect. Though one may laugh at most of these observations, the humor in each is derived from a painful kernel of truth.



Moore's Law - In 1965, Gordon Moore, at the time a researcher at Fairchild Semiconductor and later a co-founder of Intel Corp., speculated on the future of the microchip. Moore said he expected that the number of transistors per processor would double every 18 months. This prediction has proved remarkably accurate for nearly 40 years and has come to be known as Moore's Law. It is sometimes expressed in a slightly different form nowadays: Computing power doubles every 18 months.

Last year, Moore suggested that his law will run up against the laws of physics in 2017. A major factor is the limits of optical lithography. "We use light to print the patterns of circuits, and we're reaching a point where the wavelengths are getting into a range where you can't build lenses anymore," Moore said.

In 2007, Intel expects to produce chips using a 0.045-micron process with a gate oxide layer only three atoms thick. It's hard to imagine many more doublings from there, even with further innovation in insulating materials.

Moore's optimistic rule of thumb is complemented by a law of despair. In his classic book The Mythical Man-Month, IBM project manager Frederick P. Brooks stated that adding programmers to a late project could only make the project later. He formalized this observation in a formula that we now know as:

Brooks' Law - The complexity and communication costs of a project rise with the square of the number of developers, while the work done rises only linearly, at best.

For decades, Moore's law has rescued computer projects that were threatened by Brooks' Law. However, the success of Linux and other open-source software projects suggests that there may be a loophole in Brooks' Law:

Linus' Law - "Given enough eyeballs, all bugs are shallow," according to Linux creator Linus Torvalds.

The sheer size of Linux's distributed development team means that somewhere there is someone who can glance at a module and detect an error that other programmers find elusive. Somewhere there is a programmer for whom fixing such a bug is a simple matter. The more developers there are on the project, the more likely it is that the team will include these programmers. Given enough developers, the existence of one who is exactly the right fellow for the job also approaches certainty.

Murphy's Law - Anything that can go wrong will - usually in the worst possible way.


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