It's a real patent

In an earlier post, I mentioned that somebody managed to get a patent for the doubly-linked list. A friend told me it was a hoax, so I did a little research. Turns out, it was not a hoax - Ming-Jen Wang of LSI was awarded patent number 7028023. The friend who told me it was a hoax is no longer a friend.

On the other hand, it's not simply the doubly-linked list that was patented. It was a tertiary list of pointers for indexing on top of the doubly-linked list. That is, a doubly linked list allows you to iterate through the items forward and backwards by some key field. Wang's patent is on adding another key field that you can iterate through the list by something other than the key field. So it appears one of two things is going on here: 1) I totally don't understand the patent (entirely possible - feel free to correct me if that's the case), or 2) a patent was awarded to an incremental improvement of an existing algorithm by implementing the same algorithm a second time. Like making a brick wall stronger by using a second layer of bricks.