Message-ID: From: "Glenn McCorkle" Organization: Arachne Fan Club Date: Mon, 13 Nov 2000 20:52:24 -0500 X-Mailer: Arachne V1.67 To: opendos AT delorie DOT com Subject: Re: LZW (was PKZIP 2.50 for DOS) MIME-Version: 1.0 Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 8bit Reply-To: opendos AT delorie DOT com Joe, Sorry to disagree with you but..... I have just now returned from http://www.pkware.com/ where I used thier search engine to look for anything on the site which might contain the letters "LZW" This is the only document it found. Search Results Keywords (any terms, case insensitive): lzw (189 files searched; 1 match found) Matches 1 - 1 http://www.pkware.com/appnote.html And in that document (82 kb in size), you will only find "LZW" at the very bottom where it mentions a reffernce book which was used to collect information for the "Appnote". Nelson, Mark, "LZW Data Compression", Dr. Dobbs Journal, Volume 14, Number 10, October 1989, pages 29-37. A search for "unisys" found nothing at-all. Search Results Keywords (any terms, case insensitive): unisys (189 files searched; 0 matches found) No documents match your search criteria! You might want to revise them and try again. On Mon, 13 Nov 2000 12:26:03 +1100, Da Silva, Joe wrote: > Hmmm ... > I'm no expert on this, so perhaps some subtlety has "escaped me". > However, as far as I can determine, the PKZIP compression method > #1 (shrinking), uses LZW (presumably with the consent of Unisys) ... > Regarding LZW, I wonder when this infamous patent will expire??? > Joe. >> -----Original Message----- >> From: Glenn McCorkle [SMTP:glennmcc AT cisnet DOT com] >> Sent: Saturday, 11 November 2000 11:55 >> To: opendos AT delorie DOT com >> Subject: Re: PKZIP 2.50 for DOS >> Well..... >> PKzip and PKunzip don't support the LZW format either. >> That's because LZW is not a compression format for archiving utilities. >> It's the compression format for GIF graphics files. >> And yes, Unisys/Compuserve owns the rights to GIF/LZW >> Not many people realize that the LZW algorithm can also used for TIFF and >> JPG >> For an in-depth explanation..... >> http://www.whatis.com/WhatIs_Definition_Page/0,4152,214337,00.html >> Oh, and the term is "floppy disk spanning". ;-) >> On Fri, 10 Nov 2000 16:30:52 +1100, Da Silva, Joe wrote: >> > Well, yes and no. >> > Yes, because it's free and (IIRC) open-source. >> > No, because it doesn't support that compression >> > type that Unisys has a patent on (LZW?), so I >> > guess it won't decompress a file using this. >> > Also, no because it *still* (last time I checked !!!) >> > doesn't support floppy disk spawning (have I got >> > that terminology right ... ?). >> > Joe. >> >> -----Original Message----- >> >> From: Florian Xaver [SMTP:dos DOT fire AT aon DOT at] >> >> Sent: Saturday, 11 November 2000 4:53 >> >> To: opendos AT delorie DOT com >> >> Subject: Re: PKZIP 2.50 for DOS >> >> Another, better solution is to use INFOZIP. You can find it at >> >> www.opus.co.tt/dave/. >> > ----- snip ----- -- Glenn (your friendly neighborhood compu-nerd) http://www.delorie.com/listserv/mime/ http://freedos-32.sourceforge.net/