From: John Montgomery (johnm@sun1x.res.utc.com)
Date: 10/14/92 

From: johnm@sun1x.res.utc.com (John Montgomery)
Subject: Use of zip instead of compress
Date: Wed, 14 Oct 1992 16:03:23 GMT

I believe the use of zip, rather than compress, as suggested by Bill
Davidsen and Lars Wirzenius, has considerable merit. Here is an example
from the XFree86 1.1 distribution. The compressed xprog2.1.tar is

-rw-r--r-- 1 johnm sys 1048686 Oct 05 23:06 xprog2.1.TZ

If I do

 cat xprog2.1.TZ|zcat|zip >xbin2.1.zip

then I have

-rw-r--r-- 1 johnm sys 697952 Oct 14 10:56 xprog2.1.zip

which is roughly 2/3 the size of the compressed file. The unpacking
can be done by

 unzip -p xprog2.1|tar xf -

or

 cat xprog2.1.zip|funzip|tar xf -

the latter being useful in the case of a zip split into several individual
files, as with zipsplit.

I often uncompress and zip before writing floppies to save space. This
would be especially useful for archive sites with limited space, and for
those doing modem downloads. The use of tar on the end of the pipe means
that all filesystem attributes will be preserved, just as with tar.Z files.

It is possible that zip is not the best choice, but it looks better than
zoo, at least in this example. If I do

 cat xprog2.1.TZ|zcat|zoo fh >xprog2.1.zoo

the resulting file is

-rw-r--r-- 1 johnm sys 753830 Oct 14 11:12 xprog2.1.zoo

and it took roughly twice as long (on my machine). It is possible that
lha, yabba, or freeze (or something else) may be better, but I don't have
them available to try.

So the use of zip looks advantageous, but it's best to be cautious. Can
anyone suggest any disadvantages to the use of zip that are not overcome by
the method above?