Many thanks for that Mark. I think my memory need replacing :)

Alf

Mark Gordon <mtg### [at] mailbagcom> wrote in message
news:39421BB5.AB8BA839@mailbag.com...
> Alf Peake wrote:
> >
> > When this HooHa started I was under the impression that the
algorithm
> > was patented _after_ CS produced the GIF format but before Unisys
was
> > involved. I was wrong?
>
> Digging out books...
>
> 1984 - LZW compression invented and written up in IEEE Computer
> 1985 - LZW patent approved
> 1986 - Sperry (patent holder) merged with Burroughs to form Unisys,
not
> quite a purchase like I remembered
> 1987 - CompuServe creates GIF
> 1993 - Unisys becomes aware that GIF uses LZW compression
>
> This paraphrased from Encyclopedia of Graphics File Formats, 2nd ed.
>
> -Mark Gordn

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