

 THE XPK DATA COMPRESSION PACKAGE
 ================================
 
 TABLE OF CONTENTS
 -----------------
 
 1. What is XPK
 2. Installation
 3. XPK-Compressors
 4. XPK-Applications
 5. Usage notes
 6. Programming
 7. Contact addresses
 8. Legal issues
 
 
 
 1. What is XPK
 --------------
 
 For a long time, there have been various compression programs for different
 purposes on the Amiga. But every application supported only one compressor,
 and most compressors were only supported by one application. XPK wants to
 put an end to this: Every application with XPK interface can use very packer
 with XPK interface. An XPK packer is a library with a four letter library
 name.
 
 
 
 2. Installation
 ---------------
 
 You can either double-click the 'Install' icon in the distribution, or you
 cd to the directory where you unpacked XPK and type
 
   copy libs libs: ALL
 
 For installing the various applications, refer to their documentation.
 
 
 
 3. XPK-Compressors
 ------------------
 
 First a general overview of the most important packers and crypters and
 their uses.
 
 - NUKE is currently the best compressor for files that are compressed once
   and decompressed many times, since it has a reasonable compression factor
   at an excellent decompression speed. Typical applications: On-disk and
   on-harddisk compression of data, e.g. for XFH.
 
 - BLZW compresses very quickly and thus can be used for data that are 
   compressed at least as often as decompressed. Probably the most suitable
   packer for backup systems, unless you have a fast CPU and a slow backup
   medium.
 
 - FEAL encrypts data at reasonable speed with very high safety, ie. it has
   not yet been broken in the higher-round modes. Any kind of private data
   is safe in the hands of FEAL.
 
 
 Now for the complete overview of all existing compressors. You may not have
 all of them. The meaning of the fields:
 
 Name: 4 letter name of the packer.
 CSpd: Compression speed in K/sec on an A3000
 USpd: Decompression speed in K/sec on an A3000
 CF  : Compression factor in %
 Mo  : This packer supports modes
 Cry : This packer can encrypt
 Desc: Description of the packer
 
 
 Name CSpd USpd CF Mo Cry Desc
 ---- ---- ---- -- -- --- ----
 BLZW  139  364 32  +  -  Fast compression & decompression, usable CF
 CBR0  410 1918  3  -  -  Byte run encoding, only for simple files (Gfx)
 DLTA  104 1265  -  -  -  Pre-processor for packing of sound samples
 ENCO  393  393  -  -  +  Sample library for cryptors
 FEAL  109  109  -  +  +  Encryption with selectable safety
 HUFF   88  138 24  -  -  Huffman coding, low CF and speed
 IDEA   90   90  -  +  +  Safe Encryption, not too fast, many variations
 IMPL    6  280 44  +  -  Imploder, good CF, slow compression, fast decomp
 NONE 1918 2477  0  -  -  Do-nothing packer
 NUKE   36  630 45  -  -  Very fast decompression, good CF & fast compression
 RLEN  170 1351  4  -  -  Sample library for packers
 SHRI    5    9 52  +  -  Excellent CF but low speed
 VERN  861  874  -  -  +  Less safe but very fast Vernam encryption
 ---- ---- ---- -- -- --- ----
 
 Also, XPK supports powerpacker.library for decompression. 
 
 
 
 4. XPK-Applications
 -------------------
 
 These is a complete list of the XPK applications known to me.
 
 XFH          (De)compressing filesystem
 xDrop        File (un)packer for OS 2.0 with intuition interface
 xPack        File (un)packer with OS 2.0 style shell interface
 xPK          File (un)packer with UNIX style shell interface
 xUP          File unpacker with UNIX style shell interface
 xDir         Shows files and their packing status
 xQuery       Shows available packers and their properties
 xLoadSeg     Allows loading of XPK-packed executables
 Most         Text displayer with mouse support for OS 2.1
 MultiPlayer  Universal module player with XPK decompression
 MoisePlayer  Universal module player with XPK decompression
 DeliTracker  Universal module player with XPK decompression
 ShowIFF      IFF image displayer with XPK decompression in iff.library
 AShow        IFF image displayer with XPK decompression in iff.library
 MoviePro     Movie/Anim 5 player with XPK decompression in iff.library
 GL           Anim player for .gl format
 Kwikbackup   Harddisk to diskette backup system
 
 
 
 5. Usage notes
 --------------
 
 XPK has been created to save space on your disks, less for file compression
 in order to transmit them. The idea behind XPK is you compress your files
 and keep using them as if they were uncompressed. On harddisk, you can use
 XFH to compress any kind of data since the application doesn't notice they
 are compressed. On diskette, you only can compress the types of data that
 a decompressing application exists for, like IFF pictures and ShowIFF.
 
 Please note that compression is always a risk. There is a possibility
 for errors in the compression algorithm, and if one single bit is
 corrupted in a compressed file, the whole file is lost. Thus, do not
 compress vital data like program source codes or private letters; we do
 not take any responsibility for lost data. Please report bugs to the
 respective author immediately; you might keep other from loosing data.
 
 
 
 6. Programming
 --------------
 
 XPK has a very easy-to-use interface for application and compressor 
 programmers. Support files exist for SAS, DICE, GCC and Aztec C,
 most assemblers, Modula and Oberon. There is a developer package,
 xpkXX.lha  (where XX is the version number, e.g. 25 for 2.5) which
 can be found on Aminet. Aminet is a number of FTP sites that share
 files. Main site is amiga.physik.unizh.ch (130.60.80.80) where XPK
 can be found in pub/aminet/util/pack.
 
 
 7. Contact addresses
 --------------------
 
 Almost all XPK authors have an e-mail address. I list the most important 
 ones here; check the application/packer documentation if you don't find
 someone here.
 
 Urban Dominik Mueller    umueller@amiga.physik.unizh.ch   XPK, NUKE
 Bryan Ford               bryanf@hpmcaa.mcm.hp.com         XPK, BLZW
 Peter Struijk            winfjmf@dutiws.TWI.TUDelft.NL    IMPL
 Christian von Roques     roques@karlsruhe.gmd.de          FEAL
 Andre Beck               beck@freia.inf.tu-dresden.de     IDEA
 Marc Zimmermann          zimmerma@ibr.cs.tu-bs.de         HUFF
 Kristian Nielsen         bombadil@diku.dk                 XFH
 Martin A. Blatter        blatter@amiga.physik.unizh.ch    xDrop
 Matthias Scheler         tron@uni-paderborn.de            xPack
 
 
 
 8. Legal issues
 ---------------
 
 This package may be freely distributed, as long as it is kept in its
 original, complete, and unmodified form.  It may not be distributed by
 itself or in a commercial package of any kind without my permission.
                                                                           
 These programs are distributed in the hope that they will be useful, but
 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 or FITNESS FOR A PARTICULAR PURPOSE.
 
  -Urban Dominik Mueller  umueller@amiga.physik.unizh.ch
