EKR <ekr(_at_)rtfm(_dot_)com> writes:
I'm quite aware that there are a number of free implementations of
compression and that the authors claim that those implementations are
enencumbered,
If any patent did cover zlib, the fact that half the planet uses it and the
patent holders haven't taken any action would make their case pretty
difficult in court.
discussions with holders of the various patents (Hi/Fn comes to mind) seem to
indicate that they feel otherwise.
... and they'd be very happy to sell you something based on their claims.
Any claim that Hi/Fn may make about coverage of zlib is completely bogus,
they're either referring to the Waterworth patent which covers what's
generally known as the LZRW1 algorithm (the exact same algorithm was also
patented by Gibson and Graybill (isn't the US patent system wonderful? :-),
LZRW1 isn't even remotely similar to zlib), or more likely the Whiting
patent, for which noone's ever really been able to explain how it differs
from LZSS which was published about a decade earlier. This is probably why
Stac have never tried to enforce it (they went after MS with Waterworth).
Were any representatives of the data compression community present at these
meetings? They would have shot down claims like this fairly quickly, these
things have been analysed to death in comp.compression. Any claims that you
can get into trouble for using zlib are about as valid as claims that you
have to pay Hitachi every time you use SHA-1.
Peter.