Z:gnu-www-ja-limit-patent-effect--ad4988-When Dan Ravicher of the Publi/en

When Dan Ravicher of the Public Patent Foundation studied one large program (Linux, which is the kernel of the  GNU/Linux operating system) in 2004, he found 283 US patents that appeared to cover computing ideas implemented in the source code of that program. That same year, a magazine estimated that Linux was .25% of the whole GNU/Linux system. Multiplying 300 by 400 we get the order-of-magnitude estimate that the system as a whole was threatened by around 100,000 patents.