>"Mark Wagner" <mar### [at] gtenet> wrote in message
>news:394313ef@news.povray.org...
>>
>> Mark Gordon wrote in message <39421BB5.AB8BA839@mailbag.com>...
>> >1984 - LZW compression invented and written up in IEEE Computer
>> >1985 - LZW patent approved
>
>What I do not understand:
>
>When LZW was published 1984,
>how can it be patented in 1985?
>
>I mean as soon as I publish an idea in a newspaper,
>it's not any more possible to patent it,
>because the idea is general knowledge because
>was published before

That's not quite correct. The "prior art" rule prevents people from
patenting things which they did not invent themselves (otherwise
somebody might patent the wheel and then sue all the car manufacturers).
If you invent something, you can certainly show it or describe it to any
number of people and still patent it. However, it might be somewhat
difficult to prove that you are the inventor, if you show it to too many
people. As other people already pointed out, it takes some time to
approve a patent (if fact, 1 year seems to be remarkably short!).

However, I don't understand something else: When the issue first came up
in 1993, everybody seemed to think that only the compression algorithm
was covered by the patent, not the decompression (That's why gzip can
read .Z-files, but cannot create them). However, the patent cited here
very clearly mentions decompression, too. Are there two patents about
LZW?

	hp

-- 
   _  | Peter J. Holzer    | Nicht an Tueren mangelt es,
|_|_) | Sysadmin WSR       | sondern an der Einrichtung (aka Content).
| |   | hjp### [at] wsracat      |    -- Ale### [at] univieacat
__/   | http://www.hjp.at/ |       zum Thema Portale in at.linux

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