[mercury-users] Compression library

Tyson Dowd trd at cs.mu.OZ.AU
Mon Mar 6 15:31:03 AEDT 2000

On 04-Mar-2000, Ralph Becket <rbeck at microsoft.com> wrote:
> There was a request here recently for a compression
> library.  I have an highly optimized LZW library, but
> I'm unsure of the IPR issues - as far as I can tell,
> LZW is still under patent.  Can anybody tell me what
> the deal is here?

I just looked into it.  LZW is patented.

Free software was once exempted by Unisys, but they decided to change
their mind on this in 1996.  

The patent expires in 2003.  

It's not clear how far their patent reaches internationally.  IBM and
BT have similar patents.  It seems to be the case that there is no
patent in Australia.  Still, Unisys would surely send out threatening
letters and try to close down your host regardless of which country you
are in.

For a boring (and infuriating) account of the situation see


The quantum sort: 
	while (!sorted) { do_nothing(); }
Tyson Dowd   <tyson at tyse.net>   http://tyse.net/
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