Hence Microsoft has decided to move a little further into the ring and be a little more precise as to the number of patent infringements it sees in free and open source software. The number is 235, according to an interview given to Fortune magazine over the weekend in America.

This time, the man making the claims, Microsoft's licensing chief Horacio Gutierrez, has provided a break-up: the kernel is said to violate 42 patents, the various GUIs 65, OpenOffice.org 45, email clients 15 and other assorted programs 68.

This is not surprising given that Dan Ravicher of the Public Patent Foundation cited a figure of 283 possible infringements in a survey he did for the Open Source Risk Management Group three years.

Blame it all on S. Pal Asija. Nearly 26 years ago, after struggling for seven years, Asija received the first software patent for SwiftAnswer. Ever heard of it? SwiftAnswer was an application used for data retrieval. Few have heard of it - the point Asija, a patent lawyer and programmer, was trying to make was that software could be patented. Until then software was considered to be written work and was protected by copyrighted, not patent law.

But enough of history. What happens now? It's evident from the interview that Microsoft still isn't prepared to publicly make threats of suing people.

The whole idea is to now approach clients and hustle them into signing deals. No big client - like WalMart for example - wants to change operating systems on mission-critical servers. They would much rather pay a licence fee.

And once the big people had been brought in line, the smaller folk would follow. These extortion schemes only work if someone blinks.

On the other side of the ring, there are plenty of big names which have their own interests in seeing that no patent payments are made - IBM, Sony, Phillips, NEC, Red Hat and others. Each has its own patent portfolio and can counter-sue if Redmond decides to go down the legal path.