Lesson of the day
The difference between copyright and patent.
Some time in the late eighties, a small company came up with this program that squashed all the "air" out of EXE files on MS-DOS systems. I remember a drop of over 50% on some files. It was awesome. At that time, hard drive space was still a premium. If memory serves, it made a noticeable difference when you ran it on some large programs.
Now, the company did not get a patent on the process. They did copyright the software. Well, It turns out that what they were doing was not all that difficult. It was amazing. The next version of all the major C compilers made smaller EXE files. I can hear the meetings that must have gone on. "Why the hell is this program able to make our EXE files smaller and everything still works?"
Anyway, The little company basically lost their shirt. If they had been able to patent the process, all those compiler companies would have had to talk to them before adding similar functionality to their software. I bet it is easy to just eliminate the "air" from the compile in the first place, so the compiler folks may have had a chance at beating the patent, but you get my point. The copyright only protects that set of code. The patent protects the process.
This is why so many large software companies want software patents and so many small companies and individuals do not.