Re: XOR [ was: Linux stifles innovation... ]
Sat, 17 Feb 2001 10:12:38 -0800

> > 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.

On Fri, Feb 16, 2001 at 09:20:34PM -0500, David Relson wrote:
> 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!

In 1984 I received a demand letter for $10,000 from the above
referenced company as a unlimited license for use of a that
patent and another patent.

At the time I ran a company that made graphics cards for IBM PCs.

Brian Litzinger <>

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