True diversity, Charney said, would require thousands of different operating systems, which would make integrating computer systems and networks virtually impossible. Without a Microsoft monoculture, he said, most of the recent progress in information technology could not have happened.

Another difference: computers can be unplugged from the network and rebooted; organisms cannot.

The theory also has skeptics outside of Microsoft.

....Mike Reiter of Carnegie-Mellon University and Stephanie Forrest, a University of New Mexico biologist who has been gleaning lessons for computer security from living organisms for years, recently received a $750,000 National Science Foundation grant to study methods to automatically diversify software code.

Daniel DuVarney and R. Sekar of the State University of New York-Stony Brook are exploring "benign mutations" that would diversify software, preserving the functional portions of code but shaking up the nonfunctional portions that are often targeted by viruses.

Geer - who continues to consult, lecture and work with a startup these days - believes monoculture theory points the way to possible solutions that are dramatic, and haven't always been followed. They would require, for example, banning from the Internet computers whose software hasn't been updated with the latest anti-virus patches. And making sure every idiot with a computer and an Internet connection knows not to open email attachments from people they don't know, or during a virus siege like over the last couple of weeks.

Beyond that, if they can make email compatible, why can't they make operating systems compatible? Or is it that they (Microsoft, Apple) don't want to? I don't know enough about the technical side of this to offer any intelligent input. why can we have any number of railroad companies running on the same tracks and not any number of operating systems that can do likewise? What do our coder friends think?