re: XOR [ was: Linux stifles innovation... ]

David Relson (relson@osagesoftware.com)
Fri, 16 Feb 2001 21:20:34 -0500

At 08:52 PM 2/16/01, you wrote:
> On Fri, 16 Feb 2001, Michael H. Warfield wrote:
> > > You know XOR is patented (yes, the logical bit operation XOR).
> > But wasn't that Xerox that had that?
>
> US Patent #4,197,590 held by NuGraphics, Inc.

The patent was for using the technique of using XOR for dragging/moving
parts of a graphics image without erasing other parts. Also, since the
patent was granted in 1980, the inventors have had their 17 years of patent
protection, and we're all free to use the technique - legally!

David

P.S. Given that XOR is a basic boolean operation, I don't think the USPTO
would ever be so dumb as to grant a patent on it. But, then the PTO has
shown a creative ability to grant patents to questionable ideas, so who can
say what they would/could/will do?

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