Subject: Info on ARC/ARJ/LZH/ZIP/ZOO/LBR/Compressed/Squeezed files (950620)
From: [email-masked] (Keith Petersen)

[File: /SimTel/msdos/starter/00-files.doc        Revised: Jun. 20, 1995]

All about ARC, ARJ, LZH, ZIP, ZOO, LBR, Compressed and Squeezed files

Some of the files available from SimTel, the Coast to Coast Software
Repository (tm), have been transformed by using one of the standard
freely-distributable utilities that either SQueezes, LiBRaries, ARChives,
ARJs, LZHs, ZIPs, or ZOOs files.  Some files in other collections have
been compressed.

This transformation is performed to compress the files to minimize
download time, and/or combine several related files into a single
easily-managed file.  You cannot use or run any of these files without
first transforming them back to their original state.

These processed files are specially named with a file type that signifies
the transformation.  These are:

            .arc   for files archived with PKPAK.EXE
            .arj   for files archived with ARJ.EXE
            .lbr   for files libraried with LU.EXE
            .lzh   for files archived with LHA.EXE
            .zip   for files archived with ZIP.EXE
            .zoo   for files archived with ZOO.EXE
            .?q?   for squeezed files (middle letter is a Q).
            .gz    for files compressed with gzip
            .Z     for files compressed with compress

                          ARC FILES

PKPAK is used to create and maintain file archives.  An archive is a
group of files collected together into one file in such a way that the
individual files may be recovered intact.  PKPAK will automatically
compress member files when adding them to the archive, and PKUNPAK will
expand them upon extraction.  For files with the .ARC extension, you must
have a copy of file /SimTel/msdos/archiver/pk361.exe to extract the
component files.  PK361.EXE is a "self-extracting archive."  When you run
this program, it will produce PKPAK, PKUNPAK and related documentation.
After you end up with a copy of PKUNPAK you can use it to extract files.
An example of using PKUNPAK to unpack an ARChive "FILE.ARC" is:
                     "A>pkunpak file"
You do not need to supply the ARC file type when specifying "file."

                          ARJ FILES

ARJ is used to create and maintain file archives.  An archive is a
group of files collected together into one file in such a way that
the individual files may be recovered intact.  ARJ will automatically
compress member files when adding them to the archive, and will expand
them upon extraction.  For files with the .ARJ extension, you must have a
copy of file /SimTel/msdos/archiver/arj241a.exe to extract the component
files.  ARJ241A.EXE is a "self-extracting archive."  When you run this
program, it will produce ARJ and related documentation.  After you end up
with a copy of ARJ you can use it to extract files.  An example of using
ARJ to unpack a ARJ archive "FILE.ARJ" is:
                     "A>arj e file"
You do not need to supply the ARJ file type when specifying "file."

                          LZH FILES

LHA is used to create and maintain file archives.  An archive is a
group of files collected together into one file in such a way that the
individual files may be recovered intact.  LHA will automatically
compress member files when adding them to the archive, and will expand
them upon extraction.  For files with the .LZH extension, you must have a
copy of file /SimTel/msdos/archiver/lha213.exe to extract the component
files.  LHA213.EXE is a "self-extracting archive."  When you run this
program, it will produce LHA and related documentation.  After you end up
with a copy of LHA you can use it to extract files.  An example of using
LHA to unpack an LZH archive "FILE.LZH" is;
                     "A>lha x file"
You do not need to supply the LZH file type when specifying "file."

                          ZIP FILES

ZIP is used to create and maintain file archives.  An archive is a
group of files collected together into one file in such a way that the
individual files may be recovered intact.  ZIP will automatically
compress member files when adding them to the archive, and UNZIP will
expand them upon extraction.  For files with the .ZIP extension, you
must have a copy of file /SimTel/msdos/zip/unz512x.exe to extract the
component files.  UNZ512X.EXE is a "self-extracting archive."  When you
run this program, it will produce UNZIP.EXE and its documentation.  After
you end up with a copy of UNZIP you can use it to extract files.  An
example of using UNZIP to unpack an archive "FILE.ZIP" is:
                     "A>unzip file"
You do not need to supply the ZIP file type when specifying "file."

The companion program to create ZIP files is /SimTel/msdos/zip/zip20x.zip.

Also available: /SimTel/msdos/zip/pkz204g.exe - PKWare's fast ZIP and
UNZIP programs (a self-extracting archive).

                           ZOO FILES

ZOO.EXE is an archiving program that is similar to PKPAK and ZIP, but
it is not compatible with either.  ZOO can produce archives with long
pathnames in them (directory names as well as the file name) and it
can store comments about each file.  If you want to take apart a ZOO
archive, you will need a copy of ZOO.EXE.  The current version of ZOO
is zoo210.exe, which may be found in the /SimTel/msdos/zoo directory.
The zoo syntax for file extraction is:
                    "A>zoo e file"
You do not need to supply the ZOO file type when specifying "file."

                           LBR FILES

LU and its relatives (LUP, LUU, LUE, LUT, LU86, LAR etc.), maintain
libraries of files.  Most LU-type programs do not perform any
compression.  Because of this, most people will squeeze files before
adding them to a library if they want to save space.  If you want to
remove the component files from an .LBR file, you should have a copy of
file /SimTel/msdos/starter/lue220.com.  This will break up the library
into its component parts, and optionally unsqueeze any .?Q? files at the
same time.  The syntax for LUE would be:
                      "A>lue220 file"
where file was really FILE.LBR.

LUU.COM can be used to create a .LBR file.

                       SQUEEZED FILES

NUSQ.COM is used to unsqueeze, or expand files that have a "Q" as the
middle letter of the file type.  Such files have been squeezed, or
compressed with SQPC.COM or something similar.  These programs use
Huffman Encoding to reduce the size of the target file.  Depending on the
distribution of data in a file it can be reduced in size by 5% to 60% by
squeezing it.  If you download a file with a file type indicating that
it is squeezed, you will need file /SimTel/msdos/starter/nusq110.com to
expand it before you can use it.  The syntax to unsqueeze a file would
be:
                   "A>nusq110 file.tqt"
where file.tqt was the file you wanted to unsqueeze.  You must supply
the full file name and type.

                     COMPRESSED FILES

COMP430D is used to uncompress, or expand files that have a ".Z" file
type.  Such files have been compressed with a Unix-compatible compress
program which uses LZW encoding to reduce the size of the target file.
Depending on the distribution of data in a file it can be reduced in size
by 25% to 70% by compressing it. If you download a file with a file type
indicating that it is compressed, you will need file COMP430D.EXE from
/SimTel/msdos/compress/comp430d.zip to expand it before you can use it.
The syntax to uncompress a file would be:
                   "A>comp430d -d file.Z"
where file.Z was the file you wanted to uncompress.  You must supply
the full file name and type.

                     GZIP COMPRESSED FILES

GZIP is used to uncompress, or expand files that have a ".gz" file type.
Such files have been compressed with a compress program which uses the
same encoding as ZIP to reduce the size of the target file.  Depending
on the distribution of data in a file it can be reduced in size by 35%
to 80% by compressing it with GZIP.  You will need file GZIP.EXE from
/SimTel/msdos/compress/gzip124.zip to expand it before you can use it.
The syntax to uncompress a file would be:
                   "A>gzip -d file.gz"
where file.gz was the file you wanted to uncompress.  You must supply
the full file name and type.

                       MORE INFORMATION

For more information on ARChives, see the documentation for PKPAK/PKUNPAK
which is included in the PK361.EXE file.  For more information on ARJ
archives, see the documentation for ARJ which is included in the ARJ241.EXE
file.  For more information on LZH archives, see the documentation for
LHA which is included in the LHA213.EXE file.  For more information on
ZIP archives, see the documentation for UNZIP/ZIP which is included in
the UNZ512X.EXE and ZIP20X.ZIP files.  For ZOO archives, see the
documentation included in ZOO210.EXE and UGUIDE.ZIP.  The doc files
included with the various LU utilities will explain .LBR's, and
LUDEF5.DOC explains the layout of these files in detail.

Keith Petersen
General Manager of SimTel, the Coast to Coast Software Repository (tm)
Internet: [email-masked]           ftp://ftp.coast.net/SimTel/
Uucp: uunet!simtel.coast.net!w8sdz        http://www.coast.net/SimTel/