RE: lzw patent search
I hate to bug you again, but is this the patented basic LZW algorithm the
only Unisys patented algorithm which the GIF file format and Unix Compress
use? If you are unsure, what other patents might be involved?
On Mon, 10 Mar 2003, Tartler, Cheryl D. wrote:
> The last basic LZW patent to expire is the Canadian one.
> -----Original Message-----
> From: Drew Scott Daniels [mailto:umdanie8@cc.UManitoba.CA]
> Sent: Monday, March 10, 2003 11:23 AM
> To: Tartler, Cheryl D.
> Cc: *lzw_info; email@example.com
> Subject: Re: lzw patent search
> If I distribute an application over the Internet, it is my understanding
> that I have to wait for the LZW patent to expire in all countries or
> potentially be doing something illegal. If that is the case, then knowing
> when the Canadian patent expires only helps if I'm selling a product in
> Canada and restricting its export. I would like to know when the last
> basic LZW patent expires and what agreements for the international
> distribution of the LZW algorithm might be available.
> What Unisys patents/pending patents might cover the version of LZW that is
> used in the GIF file format, and/or Unix Compress?
> Drew Daniels
> On Mon, 10 Mar 2003 firstname.lastname@example.org wrote:
> > In Canada, the basic LZW patent expires July 7, 2004. Be advised that
> > has many patents issued and pending on variants from basic LZW.
> > From: Drew Scott Daniels <umdanie8@cc.UManitoba.CA> on 03/07/2003 03:14 PM
> > To: LZW_INFO@UNISYS.COM@SMTP@ExchangeUSBBGW
> > cc: email@example.com@SMTP@ExchangeUSBBGW
> > Subject: lzw patent search
> > Hi,
> > When do all the lzw related patents expire? I've heard different stories
> > and am confused by all the different patents that seem to exist for lzw.
> > I also am unsure as to how to search for information about each of the lzw
> > patents.
> > says:
> > including United States Patent No. 4,558,302, Japanese Patent Numbers
> > 2,123,602 and 2,610,084, and patents in Canada, France, Germany, Italy and
> > the United Kingdom.
> > and:
> > Welch Patent Licensing Department; Unisys Corporation; Mail Stop E8-114;
> > Unisys Way, Blue Bell, PA 19424. Via the Internet, send E-mail to
> > LZW_INFO@UNISYS.COM. Via facsimile, send inquiries to Welch
> > Patent Licensing Department at 215-986-3090
> > Thanks
> > Drew Daniels