After he argued in a paper published last fall that the monoculture amplifies online threats, Geer was fired by security firm @stake Inc., which has had Microsoft as a major client.
Geer insists there's been a silver lining to his dismissal. Once it got discussed on Slashdot.org and other online forums, the debate about Microsoft's ubiquity gained in prominence.
"No matter where I look I seem to be stumbling over the phrase `monoculture' or some analog of it," Geer, 53, said in a recent interview in his Cambridge home.
In biology, species with little genetic variation -- or "monocultures" -- are the most vulnerable to catastrophic epidemics. Species that share a single fatal flaw could be wiped out by a virus that can exploit that flaw. Genetic diversity increases the chances that at least some of the species will survive every attack.
"When in doubt, I think of, `How does nature work?' " said Geer, who has a doctorate in biostatistics from Harvard University.
"Which leads you, when you think about shared risk, to think about monoculture, which leads you to think about epidemic, he said. "Because the idea of an epidemic is not radically different from what we're talking about with the Internet."
Geer isn't the first to argue that the dominance and tight integration of Microsoft operating systems and software makes the global computing ecosystem vulnerable to a cascading failure.
Geer's paper did little more than make the point with particular fervor -- which only intensified when Geer was fired.
"The hoopla around him losing his job gave the story some extra frisson," said Internet security expert Bruce Schneier, a coauthor of Geer's.
Microsoft, which denies pressuring @stake to fire Geer, says the comparison between computers and living organisms works only so well.
"Once you start down the road with that analogy, you get stuck in it," said Scott Charney, chief security strategist for Redmond, Wash.-based Microsoft.
Charney says more use of the Linux open-source operating system, a rival to Microsoft Windows, might create a "duoculture," but that wouldn't deter sophisticated hackers.
