Question about Patent law.

[TursiopsAmicus]

I have a quick question.  Does anyone know what the time limits on software
patents are?  I ask because I am curious about the patent on LZW compression.
 If the documents I have read are accurate, LZW compression was patented in
1983.  Those who don't know what LZW compression is, it is the compression
algorith used in GIF files.  Software depelopers supporting gif compression
are required to pay a licensing fee.  This is a "between a rock and a hard
place" situation for web developers who want to make gifs and animated gifs
on-the-fly.  I was wondering if anyone knew anything about that situation.  I
thought it was 17 years, which would mean it expired last year.  That may
mean nothing though, because Unisys, the original patent holder, recently
patented two different *methods* of LZW compression, both of which I think
are used in gif files.  That must be an oversight on the part of the patent
office... they essentially allowed Unisys to patent LZW compression again
through allowing them to patent the methods of the compression.  If anybody
has resources on LZW, gif files (particularly animated gif files), and patent
law, I would appreciate if someone can point me to information about that.  
Thanks.

Michael Harney
[EMAIL PROTECTED]