Re: LZ: Compression program (and quest
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Re: LZ: Compression program (and quest
On Wed, 11 Sep 1996, Mike Berry wrote:
>
>
> ----------
> > From: SAM STAUFFER <sam.stauffer@aquila.com>
> > To: list-zshell@lists.ticalc.org
> > Subject: Re: LZ: Compression program (and quest
> > Date: Wednesday, September 11, 1996 4:49 PM
> >
> > -> >This method is known as the Lempel-Ziv algorithm.
> > ->
> > -> That is interesting, thanks. But how efficient is that with data
> > -> files that are more random?
> >
> > It's patended.
>
> I don't think it is patented anymore. It was invented in 1977 which was 19
> years ago. The patent therfore expired a couple years ago. It is now
> public domain. However, I am rethinking and I thought that for ZCompress
> or whatever the name will be, a arithmetic compression algorithm would work
> best. Although slow, it provides for excellent compression, which is the
> main reason for the compressor.
It might be copyrighted then. I know that lasts longer. In any
case the rights are definitly owned by Unisys. They won a court
case against Compuserve about a year or 2 ago because they used
it in their GIF format. They decided to be real easy about
pricing but they'll sue anybody that uses it without permission
in a minute. They have to to continue to protect their rights.
I wouldn't consider using LZW without their permission, but I
don't think it'll be that difficult to get permission.
Barry
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