Ask Slashdot: Using Code With an Expired Patent?

kruhft writes "I was recently doing some research into Genetic Programming and found a library through a blog post that looks to be useful. After looking over the code and license, I found that this was the first piece of code I had seen that was protected by a patent, issued on June 19, 1990. I read that patents last for 20 years, meaning that the patent that this code refers to is expired. Is there any way for me to be sure that using this code is safe from any patent troll attacks if I choose to use it? Would rewriting the code keep me from violating any other patents that the author might have regarding the use of such an algorithm? Does the code pass into the public domain after the patent expires?" Note to Chrome users: the above link ("a library") works for me in Firefox, but not in Chrome on Linux; YMMV.

Re:Rewriting doesn't help

[PatentMagus]

Yes, daedae has it right except for a few omissions. A patent that issued in 1990 would indeed be expired today, so you don't have to worry about that patent. However, there may be later patents, perhaps even a submarine patent, lurking in wait for you. Furthermore, you are never safe from patent trolls.

Copyright is probably your biggest issue though. Simply rewriting the code doesn't always work unless you take some type of positive step to ensure that the new code is "clean". For example, do not just go through the old code changing variable names and cleaning things up here and there. The folks that do clean implementations 'for real' will actually hire programmers and give them specifications but absolutely no code or psuedo-code. A little more googling may turn up another implementation. Genetic algorithms and programs were all over the place 20 years ago.

Re:no, rewriting does not protect you

[Anonymous Coward]

They leapt like superman across that line many years ago.

Re:No

[Grishnakh]

The whole point of patents was to publish the invention so that people could look at it

The late 1700s are calling and want you back.

The whole point of patents now is to provide a legal way for large corporations to block competition from smaller competitors using the court system.

Re:No

[darkchubs]

Pffffft, The bill is so watered down it does nothing good and a some bad. Reform was going to include patent validity in trial, this would have helped flush the crud out of the system... but our overlords couldn't decide if that was good for them or not, so it fall away.