Date   : Sat, 09 May 1987 11:46:00 MDT
From   : Keith Petersen <W8SDZ@SIMTEL20.ARPA>
Subject: Copyright status of ARC, LZW, and COMPRESS programs questioned

After announcing the availability of a recent update of SEA's ARC
program, I received the following message which raises serious doubts
as to the validity of the copyrights of SEA, Phil Katz, and Vernon
Berg's ARC programs and well as other LZW-type compression programs
and the status of the popular Unix "compress" program.

--Keith Petersen
Arpa: W8SDZ@SIMTEL20.ARPA
Uucp: {bellcore,decwrl,harvard,lll-crg,ucbvax,uw-beaver}!simtel20.arpa!w8sdz
GEnie Mail: W8SDZ

--forwarded message--
To: Keith Petersen <W8SDZ@SIMTEL20.ARPA>
Re: Message for the authors of ARC

I don't know how to get in touch with the authors of ARC (I didn't see
any addresses in INFO-IBMPC), but since you seem to be posting information
about new versions, etc., I thought that you might be able to forward the
following mail to them.

1) The correct spelling of the name is Ziv.  So you should call it
Lempel-Ziv (or Ziv-Lempel because that was the order of the author's
names in the original paper) encoding.

2) The original Ziv-Lempel method is patented (#4,464,650 -- Willard
Eastman, Abraham Lempel, Jacob Ziv, Martin Cohen) assigned to Sperry
Univac (now Unisys).  Since the Welch modifications are to this
method, I would think that some sort of license agreement from Unisys
would be necessary (this is really only a practical problem for
commercial customers).  Does such an agreement exist?

--end forwarded message--