             Uncompress Unix .Z Files on Different Systems
                           LI Yao    Feb, 1993

On several occasions with lytx, you may have to deal with .Z compressed files.
such as a uuencoded .Z compressed file sent to you thought email, print ready
formatted PostScript lytxnn.ps.Z, and possibly old issues, ...

In concept, it's feasible to uncompress (compress) Unix .Z files or any other
commonly used compressed files on DIFFERENT computer systems with the utilities
obtainable from many anonymous ftp sites. To understand more, please read the
Frequent Asked Question posted on Usenet newsgroup: comp.compression by
Jean-loup Gailly <jloup@chorus.fr>, Part 1, lines 423-441, or starts from
line 181.

In practice, I tried .Z uncompress utility for MSDOS on PC. It works. (Of 
course.) From ftp site 'ifcss.org', I got software/dos/utils/uncompress.exe.
Then downloded it to PC. It became uncompre.exe. Similarly I downloded 
lytx14gb.Z to PC. Next, issue 
         c:\>uncompre -K lytx14gb.Z
It uncompresses lytx14gb.Z to lytx14gb. Rename it to lytx14.gb as you wish.
If you use 'uncompre -k -K lytx14gb.Z', the input file will not be erased.

Then I tried wuarchive.wustl.edu:/mirrors/msdos/compress/comp430d.zip
Unziped it with 'pkunzip comp430d.zip'. It generated 'comp430d.exe' and
'comp430d.doc'. Then, say
         c:\>comp430d -d lytx14gb.Z
It de-compresses lytx14gb.Z to lytx14gb. Rename it to lytx14.gb as you wish.

So just be patient to read documentation/help files first, then try out.
I am sure you could install the required .Z uncompress utility on your system.

Here are two groups of information about where those .Z uncompress utilities
stored. You need one only.
 
Group 1.
anonymous ftp: ifcss.org
.Z uncompress utilities for
 - MSDOS: software/dos/utils/uncompress.exe
 - VMS:   software/vms/utils/compress.exe
 - Macintosh: software/mac/utils/maccompress-32.hqx

Group 2.
from the FAQ of Usenet newsgroup:
comp.compression by Jean-loup Gailly <jloup@chorus.fr>.

.Z: compress for Unix ('the' LZW algorithm)
      It is likely that your Unix system has 'compress' already. Otherwise:
        wuarchive.wustl.edu:/packages/compression/compress-4.1.tar
        (not in .Z format to avoid chicken and egg problem)
    compress for MSDOS
        wuarchive.wustl.edu:/mirrors/msdos/compress/comp430[ds].zip
        garbo.uwasa.fi:/pc/unix/comp430d.zip
    compress for Macintosh
        sumex-aim.stanford.edu:/info-mac/util/maccompress-32.hqx
    compress for Amiga
        ftp.funet.fi:pub/amiga/utilities/archivers/compress-4.1.lha
    compress for Vax/VMS
        wuarchive.wustl.edu:/packages/compression/vax-vms/lzcomp.exe
        wuarchive.wustl.edu:/packages/compression/vax-vms/lzdcmp.exe

If you have technical difficulties to uncompress .Z file, please contact us
with detailed problem report.  Or for TEMPORARY arrangement, get lytxnn.gb
or lytxnn.bg5 from lytx ftp sites.
 
-----------------------------------------------------------------------------
                       Important Announcement
                           Feb 10, 1993

From this issue, we start sending the uuencoded .Z compressed GB and BIG5 lytx
to you to reduce the size by 30--45%. (Hz coded lytx remains the same for
on-line reading.) 

To retrieve the GB code on Unix,
Step 1. save this file to lytxnn.uue (and delete its header part), where nn in
        lytxnn.uue is the present issue number.
Step 2. uudecode .uue file
          uudecode lytxnn.uue
        It generates lytxnngb.Z
Step 3. uncompress .Z file
          uncompress lytxnngb.Z
        It generates lytxnngb
Step 4. Rename lytxnngb to lytxnn.gb as you wish.
BIG5 code can be similarly retrived.

How much reduction? It's illustrated through the following example.
    lines  words  chars/bytes  file
     508      10     40613    lytx13.gb
     908    1037     55986    lytx13.uue (without header, before compression)
     191     437     26720    lytx13gb.Z
     597    2035     36842    lytx13.Z.uue (without header, after compression)
     734     719     53728    lytx14.gb
    1197    2044     74054    lytx14.uue (without header, before compression)
     253     615     35512    lytx14gb.Z
     793    2761     48960    lytx14.Z.uue (without header, after compression)
     
Size reduction = (74054-48960)/74054 = 0.34 = 34%
The reduction for lytx13 is 44%.

Advantages:
 - reduce the traffic density and save network resources;
 - take less disk space thus reduce the risk to flush your mail spooler/box;
 - allow a 50% maximum effective length increase, so more articles per issue.

-----------------------------------------------------------------------------
         A Subscriber's Experience of Uncompressing .Z File on PC

From 3392684@QUCDN.QueensU.CA Sat Feb 13 13:47:40 1993
Received: from QUCDN.QueensU.CA by QUCDN.QueensU.CA (IBM VM SMTP V2R2)
   with BSMTP id 6967; Sat, 13 Feb 93 13:45:16 EST
To: li@sce.carleton.ca

I tried several ways to figure it out. Finally, I made it. Take my case as 
an example, hooked with a network-facility-fully-equipped VM host from a 
distant PC, I'v gone through the the procedures listed below.

1. Receive your WONDERFUL file from my mailbox and save it onto my personal 191
   disk on mainframe, usually, as the name of "LYTXxx.UUE", in this case, as
   "LYTX14.UUE". This file now is in ASCII mode and with the ".Z" compressed
   format built inside.

2. Download 'LYTX14.UUE' to my PC in the ASCII mode, usually bearing the same
   file name.

3. Decode this revised 'LYTX14.UUE' by using 'uudecode.com' to transfer it into
   binary mode. Now a file named 'lytx14gb.Z' comes up.

4. Use 'uncompre.exe' or 'comp403d -d' to de-compress 'lytx14gb.Z'. Now 
   'lytx14gb.Z' dose not exist any more, instead, a file named 'lytx14gb' being
   generated with no extension.

5. This file, by the name of 'lytx14gb', is actually the end .GB file,   which
   could be read or viewed in a chinese editor/viewer. Or if willing to rename
   it with the extension .GB or whatever, it dosen't bother any more.

