PatentsToday Slashdot has a story on LSI patenting multiply linked lists. The patent was applied for in 2002 and granted in April this year.
I'm glad to see lots of comments on Slashdot referring to prior art. A decent lawyer could avoid the question of doubly linked lists, so I was pleased to see more complex examples from the 80's and 90's.
I was particularly bothered by this patent due to the fact that I would have inadvertantly violated it several years ago. My blog describes an RDF DB design with takes advantage of multiple links for each node in a list, so that the lists can be traversed in completely different directions. Unfortunately the posts were made in May 2004, which was well after the submission date of the patent (2002). So my work doesn't qualify as prior art.
You'd think that my own work (among others) constitutes the breaking of the "non-obvious" requirement. Apparently not. There must be a whole swathe of the software developers community who may be classified as "brilliant geniuses" by the USPTO, given that we all come up with the same non-obvious idea.
When learning programming, we are all inculcated with standard techniques. We are taught to not reinvent the wheel. Design patterns, algorithms, you name it... the state of the art in programming is to take someone else's system and build on it. Make it something new by connecting old things in new ways, or adding into existing systems. We are NOT taught which techniques to avoid due to patent problems. We are not taught how to search for possible conflicts with existing patents. In fact, the whole point of modern programming is an anathema to what patents try to enforce. So it can be really frustrating to see patents on common ideas. It can be even more frustrating when someone decides to patent something that you've worked with. I guess I should be grateful that I needed a more scalable design than the one described in that blog post.