Subject: Release Message for UNARC Program
Date: March 27, 1987

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Version 1.6 of the CP/M UNARC utility:

* Corrects a bug in version 1.5, which caused generation of an 'incorrect CRC'
  warning message (during extraction of files to disk) in certain cases where
  such an error condition did not actually exist.

Version 1.5 of UNARC included the following changes from the previous version
1.4 release:

* Provides self-unpacking archive support (see below).
* Corrects a serious bug in the non-Z80 version (UNARCA.COM), which caused
  failure to output the last 1-255 bytes of an extracted file in certain
  situations.  (In particular, ALL files less than 256 bytes in length could
  not be extracted from archives.)
* Supports the new "squashed" compression method generated by the MS-DOS
  program PKARC (version 2.0 or later).
* Provides a new command line option (P) for direct printing of files on the
  CP/M list device.
* Provides a new command line option (C) for checking the validity of archive
  files.
* Displays a checksum total of CRC values (useful for comparing separate
  copies of an archive file).
* Alters the mechanism used to avoid a problem with the LUX library/archive
  utility program, to provide independence of UNARC from recent multiple
  releases of new LUX versions by different authors.  (See USELUX definition
  in UNARCOVL.ASM overlay file.)
* Minor enhancements to tab expansion and CTRL-S/CTRL-C processing during
  file typeout.
* Expands on-line help display examples.

Complete details of all of the above changes (and past history of prior UNARC
releases) are provided in the version 1.5 source program file (UNARC.Z80).

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

UNARC is now distributed exclusively as a "self-unpacking" archive file,
UNARC16.ARK.  This allows automatic extraction of the distributed files,
without requiring access to a separate copy of UNARC.COM or UNARCA.COM.  To
utilize this capability, simply copy or rename UNARC16.ARK to a program file,
UNARC16.COM, on the current disk drive.  (The exact file name UNARC16.COM is
required.)  Then, run this program, with a single optional command line
parameter specifying the disk drive to which all distribution files will be
extracted (defaults to current disk).

For example, assuming UNARC16.ARK is on drive B:, and the files are to be
extracted to drive C:, the following CP/M commands may be used:

   A>B:                            ; Set current drive for UNARC16.ARK
   B>REN UNARC16.COM=UNARC16.ARK   ; Rename it to UNARC16.COM
   B>UNARC16 C:                    ; Run it to extract all files to drive C:

Note that this self-unpacking capability is provided only by the distributed
archive file, and it will not work if that file is altered or reconstructed.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

The following files are distributed with this release:

     Filename.Typ  Size  Recs  CRC   Description
     ------------  ----  ----  ----  -----------
  1  UNARC   .MSG    7k    50        Release message (this file)
  2  UNARC   .COM    5k    37  17B5  Program (Z80 version)
  3  UNARCA  .COM    6k    45  913C  Program (8080/8085 version)
  4  UNARC   .DOC   31k   244  A8B1  User documentation
  5  UNARC   .FOR    1k     4  23B4  Brief "what's it for?" abstract
  6  UNARCOVL.ASM   14k   111  EEC3  Overlay source for program options
  7  UNARC16 .DIF    2k    14  8E8C  Version 1.6 source code differences
  8  UNARC   .Z80  122k   969  406F  Version 1.5 source code (UNARC15S.ARK)

(The CRC values shown above are those displayed by UNARC itself, and these
should be used for verification purposes.  These are not compatible with the
values produced by other CP/M programs, such as CRCK and CHEK.)

Items 1-7 are included in the self-unpacking UNARC16.ARK file.  Item 5 may be
used to supply a requested program description after uploading UNARC16.ARK to
a remote system.  Item 6 supports all user-configurable program options.

Item 8 is distributed in a separate archive file, UNARC15S.ARK, and it is not
required for UNARC program operation or configuration.  (Due to the relatively
insubstantial nature of the version 1.6 update, the new source code file is
not being distributed.  However, item 7 may be used, in conjunction with the
SSED utility (version 2.0, by Chuck Forsberg), to generate an updated source
code file from the distributed file for version 1.5.)

				     NOTE

	8080/8085 USERS:  The file UNARCA.COM is an alternate version
	of the program which will run on your systems.  However, it is
	larger and substantially slower than the standard (Z80-only)
	version, UNARC.COM.  (UNARCA.COM will run on ALL CP/M systems,
	but it is specifically NOT recommended for users with Z80's!)

	RCP/M SYSOPS:  The assembly language overlay file UNARCOVL.ASM
	is provided primarily for your use in generating a secure
	version of UNARC for use by remote callers.  Note that several
	of the UNARC 1.6 changes had been distributed to RCP/M Sysops
	in an earlier Beta-test release (UNARC 1.42).  That version
	was also distributed with several recent releases of the LUX
	utility program (by different authors), and it should now be
	replaced by UNARC 1.6.  (If you use LUX, be sure to define
	USELUX = YES in the overlay file.)  Due to the self-unpacking
	feature of UNARC16.ARK, it is no longer necessary to provide
	separate copies of UNARC.COM and UNARCA.COM for downloading by
	first-time users.  (Even if you prefer the use of .LBR files
	on your system, you are encouraged to maintain at least this
	one file, UNARC16.ARK, in its distributed form!)

The UNARC.DOC file provides a complete program description and user operating
instructions.  Refer to the notice in that file regarding rights of use and
distribution of this program and its associated documentation files.

                    Copyright (C) 1987 by Robert A. Freed
                             All Rights Reserved

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