Re: every IP form

From: Terry Carroll <carroll[_at_]>
Date: Wed, 18 Sep 1996 10:46:03 -0700 (PDT)

On Wed, 18 Sep 1996 ArborLaw[_at_] wrote:
> >
> > PKZIP, the compression software, evidently has a patent number,
> > a copyright registration, and a trademark registration. That's a
> > single item, not something with multiple parts each under
> > different protection.
> A little hair splitting: it's true this is a single item of manufacture,
> but once again, different qualities are being protected by different
> modes.
> I haven't looked at the patent, but I suspect that it is for the data
> structure of the compression utility itself, and it is probably
> language-independent, ie, if at all possible software claims should
> read on the data structure and should be independent of platform.

I haven't looked at the patent itself, and, of course, the measure of a patent is its claims, and without those, what the patent covers is speculation. However, for those with a casual interest, here is the abstract of the PKZIP patent:

United States Patent                                     5,051,745
 Katz                                               Sept. 24, 1991

String searcher, and compressor using same

 Inventors: Katz; Phillip W. (Glendale, WI).  Assignee: PKWare, Inc. (Brown Deer, WI).  Appl. No.: 570,433
 Filed: Aug. 21, 1990

 Intl. Cl.: H03M 7/30; G06F 15/40
 U.S. Cl.: 341/ 51; 341/ 65; 341/ 67; 341/106; 364/200  Field of Search: 341/51, 65, 67, 50, 95, 106; 364/200, 900

References Cited:

                      U.S. Patent Documents

      4,558,302       Dec., 1985         Welch          341/ 51
      4,730,348       Mar., 1988         MacCrisken     364/200
      4,961,139       Oct., 1990         Hong et al.    364/200

Primary Examiner: Pellinen; A. D.
Assistant Examiner: Logan; Sharon D.
Attorney, Agent or Firm: Fuller, Ryan & Hohenfeldt


Methods and apparatus for string searching and data compression. In the string search method and apparatus pointers to the string to be searched are indexed via a hashing function and organized according to the hashing values of the string elements pointed to. The hashing function is also run on the string desired to be found, and the resulting hashing value is used to access the index. If the resulting hashing value is not in the index, it is known that the target string does not appear in the string being searched. Otherwise the index is used to determine the pointers which correspond to the target hashing value, these pointers pointing to likely candidates for matching the target string. The pointers are then used to sequentially compare each of the locations in the string being searched to the target string, to determine whether each location contains a match to the target string. In the method and apparatus for compressing a stream of data symbols, a fixed length search window, comprising a predetermined contiguous portion of the symbol stream, is selected as the string to be searched by the string searcher. If a string to be compressed is found in the symbol stream, a code is output designating the location within the search window of the matching string and the length of the matching string.

                                    12 Claims, 2 Drawing Figures 


For those unaware of it -- permits a search of the PTO's database for patent "front page" information. The above was the result of a search for all patents with an assignee-at-issue of "PKWare."

Terrence J. Carroll 
Attorney at Law                                      ph: 415/843-5090
Cooley Godward Castro Huddleson & Tatum             fax: 415/857-0663
Five Palo Alto Square            email (office): carrolltj[_at_]
Palo Alto, CA 94306-2155         email (personal):    carroll[_at_]
Received on Wed Sep 18 1996 - 17:53:30 GMT

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