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                             File Archive Utility 
                           Version 01.02.00 06/20/87 
                              for TRS/LS-DOS 6.x 
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
          (C) COPYRIGHT 1985, 1986 by System Enhancement Associates; 
                              ALL RIGHTS RESERVED 
     
    TRS/LS-DOS 6.x adaptations (C) COPYRIGHT 1986,1987 by David Huelsmann; 
                              ALL RIGHTS RESERVED 
     
     
    This document describes the ARC4 file utility, version 01.02.00,  which 
    was based on the MS-DOS ARC created by System Enhancement Associates. 
     
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 2 
     
     
                               Table of Contents 
     
     
     
    Table of contents  ...............................................   2 
    Introduction  ....................................................   3 
    Using ARC4 .......................................................   5 
    ARC4 commands  ...................................................   6 
        Adding files  ................................................   6 
        Extracting files  ............................................   7 
        Deleting files  ..............................................   8 
        Listing archive entries  .....................................   8 
        Printing files  ..............................................   9 
        Testing an archive  ..........................................  10 
    ARC4 options  ....................................................  10 
        Backup retention  ............................................  10 
        Encryption/decryption  .......................................  11 
        New Line Mode  ...............................................  12 
    MS-DOS ARC File Compatibility  ...................................  12 
    Technical Notes  .................................................  12 
    Technical Support  ...............................................  13 
    Version numbers  .................................................  14 
    Common questions and answers  ....................................  14 
    Revision history  ................................................  15 
    Program history and credits  .....................................  16 
    Site license  ....................................................  17 
    Site License Agreement  ..........................................  18 
    Order form  ......................................................  19 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 3 
     
     
                                 INTRODUCTION 
     
     
     
    ARC is the copyrighted property of System Enhancement Associates. Since 
    ARC4 is a derivative  work based  on ARC,  it,  too, is the copyrighted 
    property  of   System  Enhancement  Associates.   The  TRS/LS-DOS   6.x 
    modifications are the  copyrighted property of David Huelsmann. You     
    are  granted  a  limited  license  to use  ARC4,  and  to  copy it  and 
    distribute it, provided that the following conditions are met: 
     
    1) No fee may be charged for such copying and distribution. 
     
    2) ARC4 may ONLY be distributed in its original, unmodified state. 
     
     
    Any  voluntary contributions  for  the  use  of  this program  will  be 
    appreciated, and should be sent to: 
     
                         System Enhancement Associates 
                                 21 New Street 
                               Wayne, NJ   07470 
     
    You may  not  use  this  product  in  a  commercial  environment  or  a 
    governmental  organization without paying  a  license fee of  $35. Site 
    licenses and commercial distribution  licenses  are  available. See the 
    order form in the back of this manual for more details. 
     
     
     
    A word about user supported software: 
     
    The user supported software concept (usually referred to  as  freeware) 
    is an attempt  to provide software at low cost. The  cost of offering a 
    new product by conventional means is  staggering,  and  hence dissuades 
    many  independent authors  and  small  companies  from  developing  and 
    promoting their ideas. User supported software is an attempt to develop 
    a new marketing channel, where products can be introduced at low cost. 
     
    If  user supported software works, then everyone will benefit. The user 
    will benefit by  receiving quality products at low cost,  and  by being 
    able  to  "test drive"  software thoroughly  before  purchasing it. The 
    author  benefits  by being able to enter the commercial  software arena 
    without first needing large sources of venture capital. 
     
    But it  can only work with  your support. We're not just talking  about 
    ARC and ARC4 here, but  about all user  supported software. If you find 
    that you   are still using a  program  after a  couple  of  weeks, then 
    pretty obviously it is worth something to you, and you should send in a 
    contribution. 
     
    And now, back to ARC4: 
     
    ARC4  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. 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 4 
     
     
    ARC4 is different from other archive and  library utilities in that  it 
    automatically   compresses  the  files  being  archived,  so  that  the 
    resulting archive takes up a minimum amount of space. 
     
    When ARC4  is used to add a file to an  archive it analyzes the file to 
    determine which of three storage methods will result in  the  greatest  
    savings. These three methods are: 
     
    1) No compression; the file is stored as is. 
     
    2) Repeated-character compression;  repeated sequences of the same byte 
    value are collapsed into a three-byte code sequence. 
     
    3) Huffman  squeezing with repeated-character compression; the  file is 
    compressed into variable length bit strings, similar to the method used 
    by the SQ programs. 
     
     
    Note  that since  one of the three  methods  involves no compression at 
    all, the resulting archive entry will never be larger than the original 
    file. 
     
     
    An interesting note: It has been brought to SEA's attention that BASIC  
    programs compress to a smaller size when they are not tokenized. If you 
    are  more concerned with space than speed, you may wish to convert your 
    BASIC  programs to  ASCII form before adding  them to  an archive. Your 
    BASIC manual should give instructions on how to do this. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 5 
     
     
                                  USING ARC4 
     
     
     
    ARC4 is invoked with a command of the following format: 
     
                     ARC4 <x> <arcname> [<template> . . .] 
     
    Where: 
     
    <x> is an ARC4 command  letter  (see  below), in either upper  or lower 
    case. 
     
    <arcname> is the name  of  the archive  to  act on, with or  without an 
    extension. If  no  extension is supplied,  then  "/ARC" is assumed. The 
    archive name may include a drive specifier and it is recommended that a 
    drive  specifier be  used  when  the Add, Update,  or Move  options are 
    invoked. 
     
    <template>  is  one  or  more  file  name templates.    The  "wildcard" 
    characters  "$",  "*"  and "?" may be used for the filename  and/or the 
    extension.  The  delimeter  character  between  the  filename  and  the 
    extension  may be either the "/" or a ".". A "!" may be used to reverse 
    the sense of the wildcard following. A file name template may include a 
    drive specifier. 
     
    If ARC4 is  invoked  with  no arguments (by typing "ARC4", and pressing 
    "enter"), then a brief command summary is displayed. 
     
     
     
    The following is an example of the display when ARC4 is invoked with no 
    arguments: 
     
                      ARC4/CMD Version 01.02.00 06/20/87   
          (C) COPYRIGHT 1985,1986 by System Enhancement Associates   
                            ALL RIGHTS RESERVED  
     TRS/LS-DOS 6.x adaptations (C) COPYRIGHT 1986,1987 by David Huelsmann  
                            ALL RIGHTS RESERVED 
                      Distributed with permission of SEA 
     
  Usage: ARC4 [aumdexplvt][bn][g{password}] archive [file(s)][>*pr][>file] 
              Where:   a,u = Add (update) file(s) to archive 
                       m   = Move file(s) to archive 
                       d   = Delete file(s) in archive 
                       e,x = Extract file(s) from archive 
                       p   = Print file(s) in archive to CRT 
                       l,v = List table of contents (verbose) to CRT 
                       t   = Test archive integrity 
                       b   = Backup copy of archive retained 
                       n   = New Line Mode: Remove LF after CR 
                       g   = Garble (encrypt/decrypt) archive file(s) 
     
           Refer to program documentation for complete instructions 
         and limitations on copying and distribution of this program. 
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 6 
     
     
                                 ARC4 COMMANDS 
     
     
     
    This section describes  each  of the commands. ARC4 will accept any one 
    command at a  time. If no commands are given, then a brief command list 
    is displayed as shown on the previous page. 
     
     
     
    ADDING FILES 
     
    Files are added to an archive using the "A" (Add), "U" (Update), or "M" 
    (Move)  commands. Add and Update are the same and always  add the file. 
    Move  differs  from Add and Update  in  that the source file is deleted 
    once it has been added to the archive. 
     
     
     
    For example, if  you wish to  add a file named "TEST/DAT" to an archive 
    named "MY/ARC", you would use a command of the form: 
     
                              ARC4 a my test/dat 
                                      or 
                              ARC4 u my test.dat 
                                      or 
                              ARC4 m my test/dat 
     
    Note that ARC4 will  automatically supply the extension /ARC. You could 
    also supply the drive  specifier on the  archive without the  extension 
    such as "my:1".  ARC4 will  read this  as  MY/ARC:1. ARC4 will accept a 
    different  extension  than /ARC for the archive file if you wish. Note, 
    also, that ARC4 will accept either the slash "/" or  a period "." as an 
    extension delimeter in the extensions of files only. 
     
    If you  wanted to add all  files with a "/C"  extension, and all  files 
    named "STUFF" to an archive named  "JUNK/ARC"  located on drive 1,  you 
    could type: 
     
                            ARC4 a junk *.c stuff.* 
                                      or 
                           ARC4 a junk:1 $/c stuff.* 
     
    Note that failure to supply a drive specifier when using wildcards will 
    cause the addition of all files that  match the wildcard  on ALL drives 
    unless there are duplicate filespecs in which case ARC4 will error exit 
    back to DOS. 
     
    If  you wanted  to move all files  on  drive  2 into an  archive  named 
    "SUM/ARC" on drive 1, you could use a command of the form: 
     
                              ARC4 m sum:1 $/$:2 
     
    Note that after  the files  are placed in the  archive, they are killed 
    from the source drive. 
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 7 
     
     
     
    Archive entries  are always  maintained  in alphabetical order. Archive 
    entries may  not  have duplicate names. If you add a file to an archive 
    that already contains a  file by that name,  then the existing entry in 
    the  archive is replaced. Also, the archive itself and its backup  will 
    not be added. 
     
    You  cannot  add  two files  with the same name. In other words, if you 
    have a file named "STUFF/TXT:0" and another  file  named "STUFF/TXT:1", 
    then typing: 
     
                        ARC4 a junk stuff/$:0 stuff/$:1 
     
    will not work. 
     
     
    ARC4 does  not  save the drive  specifier or  any passwords.  In  other 
    words, if you specify a drive and/or password when adding  a file, only 
    the actual file name is stored in the archive. 
     
     
    ARC4 will never add an archive to itself, nor will it add the temporary 
    copy or a backup copy of the archive. 
     
     
     
    EXTRACTING FILES 
     
    Archive  entries are extracted with the "E" (Extract) and "X" (eXtract) 
    commands. For example, if you  had an archive named "JUNK/ARC", and you 
    wanted  all files in it with  an  extension of  "/TXT" or "/DOC" to  be 
    recreated on your disk, you could type: 
     
                            ARC4 e junk $/txt $/doc 
                                      or 
                            ARC4 x junk $/txt $/doc 
     
    Note that in the  above examples, the files would be extracted to drive 
    0. 
     
    If  you  wanted to  extract  all  of  the  files  in  an  archive named 
    "JUNK/ARC", you could simply type: 
     
                                  ARC4 e junk 
                                      or 
                               ARC4 e junk $/$:2 
     
    Note that in the first example, all files would be extracted to drive 0 
    and in the second example, all files would be extracted to drive 2. 
     
    Whatever method of file  compression was used in storing the  files  is 
    reversed, and uncompressed  copies are created. If a file with the same 
    name already exists on the  drive  specified, you will  be asked if you 
    wish to overwrite the file. 
     
 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 8 
     
    You can also specify a drive specifier, in which case the  decompressed 
    copy is placed on the  specified drive.If you give  more than one drive 
    for  a file, then  only the  first one is  used.   For example, if  you 
    typed: 
     
                     ARC4 x junk:1 trash/txt:1 trash/txt:2 
     
    then TRASH/TXT will be placed on drive 1. 
     
     
     
    DELETING FILES 
     
    Archive  entries  are deleted  with  the "D"  (Delete)  command.    For 
    example, if you  had an  archive named  "JUNK/ARC", and you  wished  to 
    delete all entries in it  with a filename  extension of "/C", you could 
    type: 
     
                                ARC4 d junk $/c 
     
    Note that deleted files cannot be  recovered  (unless you  specified to 
    keep  a backup copy  of  the  archive).  ARC4  recovers all space  from 
    deleted  files.  Note  also  that  the archive  did not  have  a  drive 
    specified.  As a  result,  the new archive (made  after  the  file  was 
    deleted) will be created on drive 0! 
     
     
    LISTING ARCHIVE ENTRIES 
     
    You can obtain a  list of the contents of  an archive by using  the "L" 
    (List) command or the "V" (Verbose list) command. Both commands display 
    exactly  the  same  thing  in ARC4.  For example, to see what  is in an 
    archive named "JUNK/ARC", you could type: 
     
                                  ARC4 l junk 
                                      or 
                                  ARC4 v junk 
     
     
    ARC4 prints a listing of an archive's contents like this: 
     
     
  Name          Length    Stowage    SF   Size now  Date       Time    CRC 
  ============  ========  ========  ====  ========  =========  ======  ==== 
  ARC4.C           27318  Squeezed   45%     15248  28 Dec 86   1:23p  69e4 
  ARC4.H            5239  Squeezed   40%      3194  28 Dec 86   1:26p  5f5d 
  ARC42.C          20620  Squeezed   44%     11617  28 Dec 86   1:26p  6d9e 
  ARC42.H           5245  Squeezed   38%      3265  28 Dec 86   1:28p  2f7f 
  ARC43.C          23682  Squeezed   43%     13538  28 Dec 86   1:28p  2a53 
  ARC43.JCL          161     --       0%       161  28 Dec 86   1:30p  4fd8 
  COMPARC.JCL        249     --       0%       249  28 Dec 86   1:31p  c134 
          ====  ========            ====  ======== 
  Total      7     82514             43%     47272   
     
     
    "Name" is simply the name of the file. 
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 9 
     
    "Length" is the unpacked file length.  In other words, it is the number 
    of  bytes  of  disk  space  which the  file would take up  if  it  were 
    extracted. 
     
    "Total" is pretty obvious, I think. 
     
    "Stowage"  is  the  compression method  used. The following compression 
    methods are currently employed: 
     
                --          No compression. 
              Packed        Runs of repeated byte values are collapsed. 
             Squeezed       Huffman squeeze technique employed. 
     
    "SF" is the stowage factor. In other words, it is the percentage of the 
    file length which was saved by compression. The total stowage factor is 
    the  stowage factor for the archive  as a  whole,  not counting archive 
    overhead. 
     
    "Size now" is the number  of  bytes the file is occupying  while in the 
    archive. 
     
    "Date"  is the  date on  which the  file had last  been  added  to  the 
    archive. 
     
    "Time"  is the time of last addition  to the archive, and is associated 
    with the date of last addition. 
     
    "CRC" is  the  CRC-16 check value which has been stored with the  file. 
    Another  CRC-16 value will  be calculated when the file is extracted or 
    tested to ensure data integrity. There is no especially good reason for 
    displaying this value. 
     
     
    Note that  you  can  specify in an "L" or  "V" command for ARC4 to list 
    just files matching a template such as: 
                               ARC4 v junk:1 *.c 
    The above example  will display a listing  of  all files that  have  an 
    extension of "C" in the archive. 
     
     
     
    PRINTING FILES 
     
    Archive  entries  may be  examined  with the "P"  (Print) command. This 
    works the same  as  the Extract command,  except that the files are not 
    created  on disk,  the high bit is set to zero, unprintable  characters 
    are converted to  periods and, the contents of the files are written to 
    the CRT.   For example, if  you wanted to see  the  contents  of  every 
    "/TXT" file in  an archive named "JUNK/ARC", but didn't want them saved 
    on disk, you could type: 
     
                               ARC4 p junk $/txt 
     
    Note that you  can pause the output to your CRT by pressing shift @ and 
    then can  resume by pressing  any key. Pressing <BREAK> during printing 
    will exit you from the program back to DOS. 
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 10 
     
    If you wanted the files  to be  printed on your  printer instead of  on 
    your screen, you could type: 
     
                            ARC4 p junk $/txt >*pr 
     
    Note that  no  check is  done  to ensure your printer is online and the 
    program may appear to "hang" until the printer is online. 
     
     
    TESTING AN ARCHIVE 
     
    The integrity of  an archive  may be tested  by use  of the  "T" (Test) 
    command. This  checks to  make sure that all  of the  file headers  are 
    properly placed, and that all of the files are in good shape. 
     
    This can  be very useful  for  critical archives, where  data integrity 
    must  be assured. When an  archive is tested, all of the entries in the 
    archive  are unpacked (without saving them  anywhere)  so that a CRC-16 
    check value  may be calculated and  compared  with the  recorded CRC-16 
    value. 
     
    For example, if you  just received  an archive  named "JUNK/ARC" over a 
    phone line,  and  you want to make sure that you received it  properly, 
    you could type: 
     
                                  ARC4 t junk 
     
    Any errors that occur  will be  displayed and  a total  count  will  be 
    given. If no errors occur on a file, it will be displayed as "okay". 
     
                                 ARC4 OPTIONS 
     
     
     
    This section  describes the  options which are available  to modify how 
    ARC4 works.  Any  of  these  options can be  combined with any  of  the 
    commands, though the result may not always  be something you'd want  to 
    do. 
     
     
    BACKUP RETENTION 
     
    When  ARC4 changes an  archive (during an Add, Update, Move, or Delete) 
    it creates a new archive with  the  same name, but with an extension of 
    "/TMP".  For example, if you add a file to an archive named  STUFF/ARC, 
    then  ARC4  will create  a new archive named  STUFF/TMP. ARC4 will read 
    from your existing  archive  and write out  the  new archive  with  any 
    changes to the "/TMP" copy. 
     
    Normally  when ARC4 is finished it deletes the original and renames the 
    new  archive  to  the  original  name  (ie. STUFF/ARC  goes  away,  and 
    STUFF/TMP  becomes the new STUFF/ARC). Among other  things, this  means 
    that  if anything goes wrong and ARC4 is unable  to  finish, then  your 
    original archive will still be intact. 
     
     
 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 11 
     
    In some circumstances you may wish  to  retain the  original version of 
    the archive as  a backup copy.  You  can do this  easily  by  using the 
    Backup option. Add the letter "B" to your command, and ARC4 will rename 
    your  original  archive  to  have  an extension of  "/BAK"  instead  of 
    deleting it. 
     
     
    In other words, if  you wanted to add "WASTE/TXT" to  an archive  named 
    "JUNK/ARC", but wanted to keep a backup copy, then you would type: 
     
                            ARC4 ab junk waste/txt 
     
    Your original archive  would  become "JUNK/BAK", while "JUNK/ARC" would 
    contain the new "WASTE/TXT" file. 
     
     
    If you keep a backup of an archive which already has a backup, then the 
    older backup copy is deleted. 
     
     
    Note that the "/TMP"  file and/or the  "/BAK" file are kept on the same 
    drive as your "/ARC" file unless you failed to add a drive specifier to 
    the archive name on the command line. In that  case, the /TMP file will 
    be created  on drive 0 and subsequently renamed to  /ARC. The /BAK file 
    wil be located on the drive where the original archive was located. 
     
     
    ENCRYPTION/DECRYPTION 
     
    Archive  entries  may  be  encrypted  and  decrypted by  using the  "G" 
    (Garble)  option. The Garble option takes the remainder of the  command 
    string as the password to use, so it must be the last option. 
     
     
    For  example, if you  wanted  to add  a file named  "WASTE/TXT"  to  an 
    archive  named  "JUNK/ARC",  and  you  wanted to encrypt  it  using the 
    password "DEBRIS", then you would type: 
     
                         ARC4 agdebris junk waste/txt 
     
    Later on, when you want to extract it again, you would type: 
     
                         ARC4 egdebris junk waste/txt 
     
     
    The password you supply  is  used to encrypt (or  decrypt) the  archive 
    entry by performing  an exclusive OR  between each  byte of the  packed 
    data and each byte of the password. The password can be any length, and 
    each of its  bytes  is used  in rotation. The password  is converted to 
    uppercase before it  is  used, so it is not case sensitive.  Since  the 
    encryption is performed on the packed data, it has no effect on stowage 
    factors. 
     
    This is not a particularly sophisticated means of encryption, and it is 
    theoretically possible to crack.   Still, since it is  performed on the 
    packed data, the result should be quite sufficient for casual use. 
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 12 
     
     
    You can, if you wish, use different passwords for different files in an 
    archive,  but it  is not advisable.  If you  are going  to  encrypt  an 
    archive, use the same  password for every  file, and  give the password 
    whenever you do anything  at  all with the archive.  It is  possible to 
    list the entries in an encrypted archive using the "L" and "V" commands 
    without giving the password, but nothing else will work properly. 
     
     
    It is advisable that you use  this option sparingly, if  at all. If you 
    should forget or mistype your password, it  is highly unlikely that you 
    will ever recover your data. 
     
     
    NEW LINE MODE 
     
    ARC4 can remove  Line Feeds after Carriage returns when extracting from 
    an archive (not during printing). This feature was  added primarily for 
    those  that attempt  to remove  stored, packed, or squeezed  text files 
    from  MS-DOS archives using  ARC4  rather than  XARC4.  This feature is 
    normally off and must be set  to on by  the user using the  "n" option. 
    For example: 
     
                            ARC4 en junk:1 $.txt:2 
     
    The above  example  will  extract  all  files ending  in /TXT  from the 
    archive  JUNK/ARC  on drive 1. While extracting these  files, ARC4 will 
    place them  on  drive  2  and  remove  all  LF  following  CR  that  it 
    encounters. 
     
    Note that this  option is automatically  forced to off even if selected 
    by the user when "A"dding, "M"oving, or "U"pdating to an archive. 
     
     
                         MS-DOS ARC File Compatibility 
     
     
     
    ARC4  uses  the exact  same  conventions in its file creation  as  does 
    MS-DOS ARC. Therefore, archives created by  ARC4 can be read by ARC and 
    extracted properly. Of course, CMD files and tokenized basic files will 
    not run under MS-DOS. Also, there has been no provision made in ARC4 to 
    add  a  line  feed after every carriage  return.  This  would  make  it 
    difficult  for  an MS-DOS ARC user to  read  text files extracted  from 
    archives created by ARC4. This is not a problem with  ARC4!  Rather, it 
    is  differing conventions used  in the  different  computers.  An  easy 
    solution  would be for the  ARC4 user to  first squeeze  the text  file 
    using SQ4/CMD  and  the  new  line option.  After  unsqueezing and then 
    adding to the archive, a line feed would follow every carriage return. 
     
    ARC4  can now read archives created by  MS-DOS ARC! It will even  allow 
    the extraction  of files that were stored,  packed, or squeezed without 
    giving error messages  and  exiting to DOS.  In the process,  ARC4 will 
    ensure that the filenames and extensions are legal for TRSDOS  and will 
    substitute  the letter  "Z"  for any character  not  legal under TRSDOS 
    conventions. 
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 13 
     
    If you wish to be able  to fully extract files from an  MS-DOS  archive 
    created  by ARC version 5.0 to 5.1.2 (probably also  works under  5.2), 
    then you should get a copy of XARC4 - now available! 
     
     
                                TECHNICAL NOTES 
     
    The  squeeze  routines are  recursive  (call  themselves)  and  require 
    varying amounts of  RAM  to  operate under. ARC4 definitely works  with 
    memory set to FA00H and will probably also work with memory set down as 
    low as F000H, however, it has not been  tested at F000H. Wildcards used 
    for filenames consume  memory. Appropriate error messages are displayed 
    if there is insufficient memory to handle the number of files recovered 
    using wildcards,  however,  it  has  been  documented that  a  wildcard 
    selection of  140 files  at one time will cause the computer to  "hang" 
    with no error message displayed. 
     
    The ARC4 help display uses space  compression codes which are  expanded 
    to  spaces upon display. If the help display appears all at the left of 
    the screen, it can be corrected by entering basic and typing: 
     
                                PRINT CHR$(21) 
     
    The space compression  codes will then work  correctly.  Unfortunately, 
    there is  no flag set that  will allow a program to determine the state 
    of the special characters and space compression status. 
     
    ARC4 is fully  compatible  with  ARC31  (the  model  1  and 3 version). 
    Archives created by  either one can  be read and  extracted from by the 
    other. XARC4  can also extract  from ARC4  or ARC31 archives as well as 
    from MS-DOS archives. 
     
    If a  problem should arise with your computer  when adding  or deleting 
    files from an archive, you could be left with only an archive with  the 
    /TMP extension  or you could have both the original  archive (/ARC) and 
    the  temporary archive.  DO NOT ATTEMPT  to access an  archive with the 
    /TMP extension for any purpose other than extraction or  listing of the 
    contents. ARC4  does NOT  expect to find a  file with the same name and 
    the extension of /TMP  on your disk. It will attempt to create  another 
    /TMP file if  you try to add or  delete. There is NO error  checking to 
    ensure that another /TMP file does not exist. A computer "hang" will be 
    the likely result. 
     
     
                               TECHNICAL SUPPORT 
     
     
     
    It should be obvious by  now that  SEA cannot provide technical support 
    even though  they wrote the original ARC that ARC4 is based on. They do 
    not  have access to the source code nor do  they have  a Model IV Tandy 
    computer. ARC4 is NOT in  the  public  domain and  can only be modified 
    with  the permission  of  the  original  copyright  holders of ARC  and 
    myself. Except for providing contributions or obtaining a noncommercial 
    or  a commercial site license, you should  not  be  contacting SEA  for 
    support for ARC4. 
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 14 
     
    Please address all inquiries concerning ARC4 technical matters to: 
     
                                David Huelsmann 
                                3308 Delamar NE 
                             Albuquerque, NM 87107 
     
                                     or to 
                                    SSE BBS 
                                (714) 963-7864 
                             1200/2400 bps anytime 
                          300 bps after 2400 Pacific 
                (Note that this BBS has moved from New Mexico) 
     
                                     or to 
                              CIS ppn 71525,1363 
     
     
                                VERSION NUMBERS 
     
     
    The version number of ARC4 is given as follows XX.YY.ZZ. 
     
    XX = a major revision, such as adding a new packing algorithm. 
     
    YY  =  an  essential  revision  that  corrects minor "bugs" or a  minor 
    enhancement that was added.. 
     
    ZZ  = a minor revision that will probably  only be  desired by specific 
    individuals or by die-hard "latest version" fanatics. 
     
    ARC4 also displays its date of last edit.  A change of the date without 
    a  corresponding change  in version  number  indicates a truly  trivial 
    change, such as fixing a spelling error. 
     
     
                         COMMON QUESTIONS AND ANSWERS 
     
     
     
    Q: Why isn't crunching available in ARC4? Crunching is much faster. 
     
    A: Actually, crunching isn't really as fast as it looks. Crunching is a 
    one  pass operation, while squeezing  requires two passes. ARC actually 
    does  the  crunching during the  analysis pass, and  puts  the crunched 
    output in a file named "$ARCTEMP.CRN". If crunching turns out to be the 
    best method, then this  temporary file is copied into  the new archive. 
    In other words, when  ARC says  "crunching" it  isn't really crunching, 
    it's just copying a file. 
     
    Also, there  are a lot of files out there that squeeze much better than 
    they crunch. 
     
    Due to the  memory  limitations of the Tandy Model  IV,  It just wasn't 
    possible to add the coding and the tables necessary to handle crunching 
    in ARC4. 
     
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 15 
     
    Q: Why does ARC4 run out of room if I make an archive bigger than about 
    180k? 
     
    A: Because  you are working on  a  floppy  disk. If you are using DS DD 
    disks, you are limited to about 180K  archive size if you add or delete 
    to  or from the archive. Of course, if you are creating a  new archive, 
    you could fill up the entire  disk (about 360K). ARC4 creates a copy of 
    your archive, incorporating any new files as it goes. When it  is done, 
    it deletes the original and  renames the new one. There are a number of 
    reasons for doing it this way, one being that your original  archive is 
    still intact if anything happens while ARC4 is running. 
     
    If  you need to make  a  larger archive, and  if you have a fixed disk, 
    then you can create  the archive on the  fixed disk and then copy it to 
    the floppy. 
     
     
    Q: Can I use ARC4 to distribute my public domain or freeware program? 
     
    A: Yes, of course. 
     
     
    Q: Can I use ARC4 to distribute my commercial software package? 
     
    A: Yes. Please contact SEA for a commercial distribution license. 
     
     
    Q: I'm a commercial user. Why should I pay for freeware that others get 
    for free? 
     
    A: Because you cannot  credibly plead poverty.  Freeware, all freeware, 
    is an  attempt  to develop  a new marketing channel to  the  benefit of 
    everyone.  You can still "test drive" freeware for a  short period, but 
    if you decide to use it in your business, then you should pay for it. 
     
     
    Q:  Why not allow me to select which method of compression I want  ARC4 
    to use? 
     
    A: It would needlessly complicate ARC4, both internally and in use. The 
    exact nature  of the  compression  methods used are complex,  and quite 
    different. The only sure way to tell  which  will be best in  any given 
    case is  to analyze the data, as  ARC4 does. The method  chosen may not 
    always be what you expect. 
     
     
    Q: How can I get the latest version of ARC4? 
     
    A: ARC4  updates are distributed through normal freeware channels,  and 
    by FidoNet. 
     
     
                               REVISION HISTORY 
     
     
    Version 01.00.00 12/11/86 of ARC4/CMD was released on 12/28/86. 
 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 16 
     
    Version 01.01.00 03/20/87  of ARC4/CMD  was  released on 03/22/87. This 
    version incorporates a number of minor fixes such as: 
    Time  display of  12:00  to 12:59 will now correctly display "p" rather 
    than "a" (This is a bug in MS-DOS ARC as well). 
    Errors  discovered  while  Testing  an  archive  will now be  correctly 
    counted rather than doubled  as in the original version (This is also a 
    bug in MS-DOS ARC). 
    Failure to supply a drivespec to an archive name will no longer cause a 
    display of extraneous characters.. 
    After  moving files  to an archive, the  display of  those files  being 
    removed will  no longer be displayed unformatted across a line but will 
    be displayed formatted as does TRSDOS. 
    The minor enhancement added in this version was  the ability to display 
    an MS-DOS archive directory and extract files that were stored, packed, 
    or  squeezed with the  appropriate coding  added to prevent problems if 
    some of the other features are attempted on an MS-DOS archive. 
    Version 01.02.00  06/20/87 of ARC4/CMD  was released  on  6/20/87. This 
    version corrects a problem introduced into 01.01.00 that caused certain 
    files added  to  the archive  to  fail the CRC-16 check. Also,  in this 
    version, removal of LF after CR was made non-automatic. 
     
     
     
                          PROGRAM HISTORY AND CREDITS 
     
     
    ARC4/CMD   is  based  on  ARC   Version  5.1.2  of  System  Enhancement 
    Associates. Thom Henderson graciously gave his permission to release  a 
    modified version of ARC for the TANDY Model IV users on 12/11/86. While 
    a number of changes and  adaptations had  to  be made  to  the existing 
    source  code  (including  eliminating  some  features  like  Lempel-Zev 
    crunching), the majority of the  program  is  the original work of SEA, 
    now,  almost 2 years  old. The following  is  the  program  history and 
    credits, as described by SEA, for MS-DOS ARC: 
     
    In  its short life thus far, ARC  has astounded us with its popularity. 
    We first wrote it in March of 1985 because we wanted an archive utility 
    that  used a  distributive  directory  approach, since this has certain 
    advantages over the more popular  central  directory approach. We added 
    automatic squeezing  in  version 2  at the  prompting of a  friend.  In 
    version 2.1  we added the code to test for the best compression method. 
    Now  (in October of  1985) we find that our  humble  little program has 
    spread across the country, and seems to have become a new institution. 
     
    We  are  thankful for the support and appreciation we have received. We 
    hope that you find this program of use. 
     
     
    If we have  achieved greatness, it is because  we  have stood upon  the 
    shoulders of giants. Nothing is created as a thing unto itself, and ARC 
    is  no  exception.  Therefore, we  would  like  to give  credit to  the 
    following people, without whose efforts ARC could not exist: 
     
     
      Brian  W.  Kernighan  and P. J. Plauger, whose book  "Software Tools" 
    provided  many of the  ideas behind the distributive directory approach 
    used by ARC. 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 17 
     
     
    Dick  Greenlaw,  who wrote  the  public domain SQ  and USQ programs, in 
    which the Huffman squeezing algorithm was first developed. 
     
    Robert J. Beilstein, who adapted SQ and USQ to Computer Innovations C86 
    (the language we use),  thus  providing  us with important parts of our 
    squeezing logic. 
     
    Kent Williams, who graciously allowed  us to use his LZWCOM  and LZWUNC 
    programs  as a basis for  our  Lempel-Zev  compression  logic, and  who 
    continues to make valuable contributions. 
     
    David  Schwaderer, whose article  in  the April 1985  issue  of PC Tech 
    Journal provided  us with  the logic  for  calculating  the CRC  16 bit 
    polynomial. 
     
    Terry  A.  Welch,  whose article "A Technique for High Performance Data 
    Compression",  IEEE Computer Vol  17 No  6  (June 1984)  seems to  have 
    started all the research on Lempel-Zev coding. 
     
    Spencer W.  Thomas, Jim McKie, Steve  Davies,  Ken Turkowski,  James A. 
    Woods, and Joe Orost, who are the authors of the UNIX compress utility. 
     
     
    And many, many others whom we could not identify. 
     
     
                                 SITE LICENSE 
     
     
    Corporate  users may wish to obtain a site license for the use of ARC4. 
    Please use the order form in this manual to order a site license.  Site 
    licenses are granted as of when SEA receives your payment. License fees 
    vary depending on the number of computers  on which  ARC4 will be used, 
    as follows: 
     
                           1 to  9 copies  $35 each 
                           10 to 24 copies  $25 each 
                           25 to 49 copies  $20 each 
                           50 to 99 copies  $15 each 
                      over  99 copies  $1500 one time fee 
     
     
    The following page is a site license agreement, which should  be signed 
    and sent with your payment when ordering a commercial site license. 
     
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 18 
     
     
                            Site License Agreement 
     
    The use of ARC4 in a commercial environment or government  organization 
    is granted under the following terms: 
     
    1.   Payment  of  the license fee must  be made  to System  Enhancement 
    Associates. The fee is  based on the number of computers  which will be 
    used to run ARC4, as follows: 
     
                           1 to  9 copies  $35 each 
                           10 to 24 copies  $25 each 
                           25 to 49 copies  $20 each 
                           50 to 99 copies  $15 each 
                      over  99 copies  $1500 one time fee 
     
    2.  You may use ARC4 on the number of computers included in the license 
    fee. If you have paid the fee for over 99 copies, then you may use ARC4 
    on any number of computers within your organization. 
     
    3.  You may make  copies of  the program, in its  original,  unmodified 
    form,  without  restriction.  You may  distribute  these  copies of the 
    program without restriction. 
     
    4.   If these copies are distributed outside of your organization,  you 
    have no obligation to control the use of those copies which are outside 
    of your organization. 
     
    5.   You  may make copies  of the  program documentation,  in both  its 
    printed form and machine readable form, without restriction. 
     
     
    6.  You may use future versions of ARC4 under this license. 
     
    7.  You may NOT  modify  the program  or charge a  fee for  copying  or 
    distributing the program. 
     
    8.  It  is  your  responsibility to  make  the necessary copies and  to 
    deliver them to the computers which they will be used on. 
     
     
     
    I agree to abide by the terms and conditions of this license. 
     
     
     _____________________________         __________________________ 
             Signature                             Date 
     
    _____________________________ 
      Name (please print or type) 
     
    _____________________________ 
             Title 
     
    _____________________________ 
           Company 
     
 
 
 
 
 
 
                                   ARC4/CMD 
    Documentation                                                Page 19 
     
     
                                  ORDER FORM 
     
     
     
    Check which items you wish to purchase: 
     
    (_) Noncommercial license for the use of ARC4. 
     
    (_) Commercial license for the use of ARC4 on ___ computers  (see price 
    schedule and terms on preceding page). 
     
    (_) Payment of $_____ is enclosed (check or money order). 
     
    (_) Please charge $_____ to my (_) Visa or (_) MasterCard: 
     
    Card number: ______________________________ 
     
    Expiration date: __________________________ 
     
    _______________________________________________ 
    Name 
     
    _______________________________________________ 
     
     
    _______________________________________________ 
    Address 
     
    ______________________   ________  ____________ 
    City                     State     Zip 
     
    _______/_______ 
    FidoNet address 
     
     
    Send this completed form to: 
     
                         System Enhancement Associates 
                                 21 New Street 
                               Wayne, NJ   07470 
     
    For commercial site license orders, please enclose a signed copy of the 
    site license agreement.

               
ARC4/CMD version 02.01.00 (released on 06/20/87) is a
TRS-80 model 4 Trsdos 6.n version by David Huelsmann that
is based upon ARC version 5.1.2 of System Enhancement
Associates. This model 4 version does NOT support the
MS-DOS 'crunching' of files or the 'old-style' headers.
This is a *MUST HAVE* utility for STANDARD $/ARC files!
 
   ARC4V102/CMD is the COMMAND file - version 1.02.00
   ARC4V102/TXT is the DOCumentation - version 1.02.00
 
Mini-DOCumentation by Guy Omer of 8/N/1 #1 at 904/377-1200
