Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uwm.edu!lakesys!mikes
From: mikes@lakesys.lakesys.com (Mike Shawaluk)
Newsgroups: comp.sys.amiga
Subject: Re: PKZip Amiga arrives
Message-ID: <1583@lakesys.lakesys.com>
Date: 19 Jan 90 20:07:57 GMT
References: <78.25B29F1F@cave.cc.andrews.edu> <26053@cup.portal.com>
Reply-To: mikes@lakesys.UUCP (Mike Shawaluk)
Distribution: na
Organization: Lake Systems - Milwaukee, Wisconsin
Lines: 75

In article <26053@cup.portal.com> Sullivan@cup.portal.com (sullivan - segall) writes:
>LHARC produces the smallest archives with PKAZIP a distant second (3-5% 
>larger.) Both archivers run at about the same speed.  ZOO and ARC produce
>similar files 10-15% larger than LHARC.  

Please qualify your statements; it is my experience that PKAZIP compresses
roughly the same (sometimes better, sometimes worse, but a small margin) as
LHARC, when it is told to use Imploding, at a better speed.  But, you don't
say which version of LHARC you are comparing to.  The current version of
PKAZIP is 1.0, which is what I assume you are using, since the beta version
only decompressed.  Also, are you comparing both compression AND expansion
speed, or just one of these?  As an independent aside, has anyone undertaken
a comparison of each of the available compression utilities, on some sort of
"benchmark" set of files (this would be a great service to the Amiga
community; I would volunteer to do so, but I consider myself too close to the
source, since I am personally acquainted with Phil Katz and Dennis Hoffman,
who are the authors of PKZIP/UNZIP and PKAZIP)

>LHARC supports protection bits, full filenames, recursive directory creation
>or search, and date/time stamps.  LHARC's major failing is that it asks you
>each time it creates a subdirectory.
>
>PKAZIP is proprietary, and has an exceptionally ugly interface, but otherwise
>does an acceptable job of file compression.  Amiga protection bits and time
>stamps are not supported to the best of my knowlege.

What is the basis for your claim of PKAZIP being "proprietary"?  If you mean
that the source code isn't in the public domain, then please say that.  The
file format is NOT proprietary, and a document describing it is distributed
with PKZIP/UNZIP for MS-DOS, as well as a short document which dedicates the
ZIP format to the public domain (these files were not distributed with the
initial Amiga release, but I will suggest to PKWARE that they be added on any
subsequent releases).  And, you are incorrect in your assertion that Amiga
protection bits and time stamps are not supported; they most certainly are.
In addition, PKAZIP also supports file comments, and offers the ability to
search a .ZIP file for a particular string in either the file name or file
comments.

I am sorry that you find the graphical interface to be "exceptionally ugly",
but I guess "each to his own".  It might be appropriate to add an "IMHO" to
the above comments (or at least "IMO").  In your assessment that PKAZIP
provides an "acceptable" level of file compression, it's interesting to note
that most people found ARC and ZOO to provide "acceptable" levels of
compression, and PK(A)ZIP exceeded each of these by a significant factor,
even with its less dense (but much faster) Shrinking algorithm.  The
imploding algorithm was developed by PKWARE after the release of LHARC (no,
it is NOT the same algorithm with minor tweaks), in an effort to keep his
software moving forward (and obviously not to lose his user base to a
different program).  As an aside, I have seen a beta version of PKZIP 1.1 for
MS-DOS, and the result of benchmarks that have been done between it and the
current version of PKZIP and other compression utilities, including LHARC.
Besides implementing a number of new features, it has improved compression,
and routinely exceeds the compression achieved by its competition.  Also,
PKWARE is also investigating claims that the Amiga version lags in
compression ratio behind LHARC, due to certain file types and structures that
are uncommon in MS-DOS (i.e., IFF files, 68000 executable images), and is
looking toward improving its algorithms to provide better compression for
these cases, WITHOUT losing any compatibility with existing .ZIP files on
either MS-DOS or Amiga  (by the way, if you have a .LZH file which was
created on your Amiga, try to extract a single file out of it on your MS-DOS
system; if the file name has any lower case characters in it, good luck!)

>ZOO's are more portable to UNIX than either ARC files or ZIP files.  LHARC
>for the Amiga currently produces files with more recent compression schemes
>than either the MSDOS version, or the UNIX version.

Pray tell, which UN*X version of LHARC are you referring to?  I've not seen a
port of LHARC in either BSD or SYSV to date.

  - Mike
-- 
   - Mike Shawaluk             
"Rarely have we seen a mailer  ->  DOMAIN: mikes@lakesys.lakesys.com 
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