Comments from Exec-PC on ZOO archive method.  10-23-86
Bob Mahoney,  Exec-PC multi-user BBS  414-964-5160

PLEASE DISTRIBUTE THIS FILE TO AS MANY SYSTEMS AS POSSIBLE.
WE DO NOT WANT TO IMPLEMENT NEW, CONFUSING STANDARDS WHEN THEY
ARE NOT WORTH THE TROUBLE!

-----------------------------------------------------------------
THE INTRODUCTION:

Just when you thought it was safe to download an ARC (ARChived)
file from a bulletin board, the problem of conflicting standards
rears it's ugly head.  The ARC format has become a stable standard
in the last year.  It has virtually replaced all other techniques
or librarying and squeezing collections of files into a single
compact file.  A new ARC technique called ZOO has appeared.  It
is similar to ARC, but it is able to compress files to a size that
is a few percent smaller than the best ARC format.  I did some
head-to-head comparisons of ZOO versus PKARC and PKXARC.  Read the
results below.  Do we need another standard?

-----------------------------------------------------------------
THE CHALLENGE:
I just performed some of my own benchmarks with the new ZOO file
archive program.  The tests force me to draw only one conclusion:
We do not need ANOTHER archive format, so forget about ZOO.  Archives
created with ZOO version 1.22 are impossible to un-ARC with the
original ARC program, with PKXARC, or with ARCE.  Even worse, ZOO
cannot un-ARC files created with any of the other archive programs!

The author of ZOO has done some great programming and documenting,
but there are a few basic concepts that must be addressed.  First of
all, new standards should be established only when the general GOOD to
the public will outweigh the PROBLEMS and CONFUSION created by the
new standard.  ZOO has a speed and size advantage when compared to OLD
versions of other ARCers, but there is no real advantage when compared
to the latest versions of PKXARC and PKARC (see results below).

The proposed new standard must be REVOLUTIONARY in its improvements
in order for it to be worthy of the losses imposed upon society in
general.  I would say a new ARC format would be revolutionary if it
consistently saved more than 20% on all files.  An occasional saving
here and there does not count.  The savings must be consistent.  The
space saving must also come with no loss of speed.

-----------------------------------------------------------------
THE COMPARISON:

The following results were achieved when compressing ZOO122.ARC
which contained the following files:

README   1ST      959  10-01-86   1:13a
ZOO      BUG     1032  10-01-86   1:11a
ZOO      DOC    39357   8-24-86   1:03p
ZOO      EXE    29038  10-01-86   9:53a
ZOOBENCH TXT     4008   9-06-86  10:46p
ZOOHSTRY TXT     5852  10-01-86  12:04p

The compression was performed in the Vdisk area of an IBM AT running
at 9 megahertz.

program     archiving time    final size of archive   extraction time
-------     --------- ----    ----- ---- -- -------   ---------- ----
Zoo 1.22       8.01 seconds       46,248 bytes          5.66 seconds
PKARC 1.2      5.45 seconds       46,671 bytes
PKXARC 3.3                                              3.88 seconds

Results: ZOO gives a space saving of less than one percent.  The time
penalty with ZOO is significant.

Now let's do a comparison with another set of files.  The author of
CHECKMATE, a home financial package, recently submitted version 1.02
to the Exec-PC BBS.  It contains the following files:

CM       000   113920   9-09-86   8:26p
CM       COM    39685   9-09-86   8:27p
CM       DOC    43392   9-30-86   7:05p
CM       HLP    44496   5-04-86   1:32p
CM       OVL    46696   9-09-86   7:15p
CMINST   COM    13239   9-09-86   8:24p

This mix of files is typical of file groups distributed on bulletin boards.

program     archiving time    final size of archive   extraction time
-------     --------- ----    ----- ---- -- -------   ---------- ----
Zoo 1.22      30.05 seconds      182,226 bytes         18.00 seconds
PKARC 1.2     18.85 seconds      184,107 bytes
PKXARC 3.3                                             10.23 seconds

Results: ZOO gives a space saving of 1.02 percent, while the PK
utilities are much faster.

By the way, the CHECKMATE system is distributed on a diskette containing
a single ARC file.  This arc file was unarced with PKXARC, since ZOO
said it had an invalid file header and was not an arc file.

-----------------------------------------------------------------
THE CONCLUSIONS:
Forget it.  Use PKxARC, ARC512, or any other program that honors the
original arc format.  We can spare the 1% penalty in disk space.

-----------------------------------------------------------------
THE END