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- File: UNARC.DOC
- Subject: User Documentation for UNARC Program
- Version: 1.6
- Date: March 27, 1987
- ------------------------------------------------------------------------------
-
-
- UNARC
-
- CP/M Archive File Extraction Utility
-
-
- Copyright (C) 1986, 1987 by Robert A. Freed
- All Rights Reserved
-
-
-
- This file provides user-level documentation and operating instructions for
- UNARC version 1.6, released March 27, 1987. Refer to the notice at the end of
- this file regarding rights of use and distribution of this program.
-
- The release message file, UNARC.MSG, provides a list of all additional files
- distributed with the current UNARC release and describes the program changes
- from the previous version 1.4 and 1.5 releases.
-
-
-
- ABSTRACT
- --------
-
- UNARC is a utility program for CP/M systems which allows the listing, typeout,
- printing, checking, and extraction of subfiles contained in "archive" library
- (*.ARC or *.ARK) files. These are commonly used for compressed file storage
- on remote access bulletin board systems. UNARC provides the CP/M user the
- ability to process such files after downloading them via modem from these
- remote systems.
-
-
-
- REQUIREMENTS
- ------------
-
- UNARC requires CP/M version 2 or higher. The program is offered in two
- versions. The standard version, UNARC.COM, requires a Z80 processor (or
- compatible equivalent, e.g. HD64180 or NSC800). An alternate version,
- UNARCA.COM, is provided for systems with 8080 or 8085 processors (or 16-bit
- systems using the NEC V20 for CP/M emulation). Identical capabilities are
- provided by the two program versions.
-
- NOTE
-
- Although UNARCA.COM can execute on ANY system capable of
- supporting CP/M, it is larger and significantly slower than
- UNARC.COM and should be avoided by users of Z80-based systems.
-
- UNARC is written in Z80 assembly language and requires only 5K bytes of disk
- storage (6K for UNARCA). As distributed, the program requires at least 30K
- bytes of available memory space (TPA) for full support of all archive file
- formats (31K TPA size for UNARCA). (Smaller systems may be able to use some
- of the program's capabilities.)
-
-
-
- ABOUT ARC/ARK FILES
- -------------------
-
- The files which UNARC processes utilize a format that was introduced by the
- ARC shareware utility program, which executes on 16-bit computers running the
- MS-DOS (or PC-DOS) operating system. This format has achieved widespread
- popularity since the ARC program first appeared in March 1985, and it has
- become the de facto standard for file storage on remote access systems
- catering to 16-bit computer users. More recently this file format has
- achieved increased popularity on RCP/M (Remote CP/M) systems.
-
- NOTE
-
- Most RCP/M system operators have adopted the convention of naming
- CP/M archive files with the filetype ARK. This differentiates
- these from MS-DOS archive files, which use the filetype ARC. This
- is a naming convention only: There is no difference in format,
- and UNARC will accept files of either type interchangeably.
-
- An archive is a group of files collected together into a single file in such a
- way that the individual files may be recovered intact. In this respect,
- archives are similar in function to libraries (*.LBR files), which have been
- commonplace on CP/M systems since 1982, when the original LU library utility
- program was introduced by Gary P. Novosielski. (However, the two file formats
- are not compatible.)
-
- The distinguishing characteristic of an ARC archive is that its component
- files are automatically compressed when they are added to the archive, so that
- the resulting file occupies a minimum amount of disk space. Of course, file
- compression techniques have also been commonplace in the CP/M world since
- 1981, when the public domain SQ and USQ "squeeze and unsqueeze" programs were
- introduced by Richard Greenlaw.
-
- The SQ/USQ programs and their numerous popular descendants utilize a well-
- known general-purpose form of data compression (Huffman coding). This
- technique, which is also utilized in ARC files, performs well for many text
- files but often produces poor compression of binary files (e.g. object program
- .COM files). The ARC program also provides an advanced data compression
- method, which it terms "crunching." This method (which is based on the
- Lempel-Ziv-Welch or "LZW" algorithm) performs better than squeezing in most
- cases, often achieving 50% or better compression of ASCII text files, 15-40%
- compression of binary object files, and as much as 95% compression of bit-
- mapped graphics image files.
-
- Five different methods are actually employed for storing files in an archive.
- The method chosen for a particular file is the one which results in the best
- compression for that file:
-
- (1) No compression ("unpacked"). The file is stored in its original form.
-
- (2) Run-length encoding ("packed"). Repeated sequences of 3-255 identical
- bytes are compressed into a three-byte sequence.
-
- (3) Huffman coding ("squeezed"). Each 8-bit byte (after run-length encoding)
- is encoded by a variable number of bits, with bit length (approximately)
- inversely proportional to the frequency of occurence of the corresponding
- byte.
-
- (4) LZW compression ("crunched"). Variable-length strings of bytes (in
- theory, up to nearly 4000 bytes in length) are represented by a single
- (maximum) 12-bit code (after run-length encoding).
-
- (5) LZW compression ("squashed"). This is a variation of crunching which
- uses (maximum) 13-bit codes (and no run-length encoding).
-
- Note that since one of the five methods involves no compression at all, the
- resulting archive entry will never be larger than the original file.
-
- NOTE
-
- The most recent release of the MS-DOS ARC program (version 5.20)
- has eliminated squeezing as a compression technique. However,
- UNARC continues to process squeezed files for compatibility with
- archives created by earlier versions of ARC and by other MS-DOS
- archiving programs (notably PKARC).
-
- The squashed compression method was recently introduced by the
- MS-DOS programs PKARC and PKXARC. UNARC can process files which
- use this method, although it is not universally accepted by other
- MS-DOS archive extraction programs (including ARC).
-
- During its lifetime, the ARC program has undergone numerous revisions which
- have employed different variations on some of the above methods, particularly
- LZW compression. In order to retain compatibility with archives created by
- earlier program revisions, ARC stores a "version" indicator with each file in
- an archive. Based on this indicator, the latest release of the ARC program
- can always extract files created by older releases (although it will only use
- the latest data compression versions when adding new files to an archive).
-
- NOTE
-
- The current release of UNARC supports archive file versions
- generated by all releases of the following MS-DOS programs through
- (at least) the indicated program versions:
-
- ARC 5.20 (24 Oct 86), by System Enhancement Associates, Inc.
- ARCA 1.22 (13 Sep 86), by Wayne Chin and Vernon Buerg
- ARCH 5.38 (26 Jun 86), by Les Satenstein
- PKARC 2.0 (15 Dec 86), by Phil Katz (PKWARE, Inc.)
-
- (UNARC does not recognize, but is unaffected by, the non-standard
- archive and file commenting feature of PKARC.)
-
- Although the above discussion has emphasized the origin of archive files for
- the MS-DOS operating system, their use has recently spread to many other
- systems. Programs compatible with MS-DOS ARC have appeared for UNIX, Atari
- 68000, VAX/VMS, and TOPS-20 systems. A CP/M utility for building archive
- files will also be available in the near future.
-
- For additional information about archive files and the MS-DOS ARC utility,
- refer to the documentation file, ARC.DOC, which is available from most remote
- access systems which utilize archive files. For additional information about
- the LZW algorithm (and data compression methods in general), refer to the
- article "A Technique for High-Performance Data Compression", by Terry A.
- Welch, in IEEE Computer magazine, Vol. 17, No. 6, June 1984.
-
-
-
- USING UNARC
- -----------
-
- The UNARC program provides an on-line help message, which is generated by
- running the program with an empty command line:
-
-
- A>UNARC
-
- UNARC 1.6 27 Mar 87
- CP/M Archive File Extractor
-
- Usage: UNARC [d:]arcfile[.typ] [d:][afn] [N|P|C]
-
- Examples:
- B>UNARC A:SAVE.ARK *.* ; List all files in CP/M archive SAVE on drive A
- B>UNARC A:SAVE.ARC *.* ; List all files in MS-DOS archive SAVE on drive A
- A>UNARC SAVE ; Same as either of above
- A>UNARC SAVE *.* N ; Same as above (no screen pauses)
- A>UNARC SAVE *.DOC ; List just .DOC files
- A>UNARC SAVE READ.ME ; Typeout the file READ.ME
- A>UNARC SAVE READ.ME N ; Typeout the file READ.ME (no screen pauses)
- A>UNARC SAVE A: ; Extract all files to drive A
- A>UNARC SAVE B:*.DOC ; Extract .DOC files to drive B
- A>UNARC SAVE C:READ.ME ; Extract file READ.ME to drive C
- A>UNARC SAVE PRN.DAT P ; Print the file PRN.DAT (no formatting)
- A>UNARC SAVE *.* C ; Check validity of all files in archive
-
-
- As shown by this help display, the UNARC utility provides the following
- capabilities:
-
- (1) Listing the directory of an archive
- (2) Extracting component files from an archive
- (3) Typing the contents of a component file at the console
- (4) Printing a component file directly on the CP/M list device
- (5) Checking the validity of an archive and its component files
-
- The particular operation to be performed is determined by the form of the file
- parameter(s) in the command line, as described separately in the sections
- which follow. The following characteristics apply to all operations:
-
- The first command line parameter must specify the name of an archive file. A
- drive name and filetype are optional. The filetype, if omitted, defaults to
- "ARK" or, if no such file exists, the alternate (MS-DOS) default "ARC" is
- assumed.
-
- The standard CP/M terminal control characters, CTRL-S (to suspend console
- output) and CTRL-C (to abort the program), may be used at any time. CTRL-K
- may also be used as an alternate for CTRL-C. Printer output to the CP/M list
- device may be obtained by typing CTRL-P at CCP command level before executing
- UNARC.
-
- In addition, by default UNARC will pause after every 23 lines of console
- output. At this time, the message "[more]" will appear at the bottom of the
- console screen. The listing may be resumed by typing any key (other than
- CTRL-S, CTRL-C, or CTRL-K, which will function as described above). If the
- space bar is used, one more line of console output will be displayed (over-
- writing the "[more]" message) and the program will again pause. If any other
- key is typed (e.g. RETURN), another 23 lines of output will be allowed to
- scroll onto the screen before the next pause. (LINE FEED may be used to
- prevent overprinting of the "[more]" line, e.g. for hard-copy terminals.)
-
- If continuous display is desired, this automatic pause feature may be disabled
- by specifying "N" at the end of the command line. The "N" must be the last
- command line character, and it must be preceded by a space. Also, there must
- be two preceding file parameters on the command line. E.g., note the
- difference between the following commands:
-
- A>UNARC SAVE N ; Typeout the file N. in archive SAVE
- A>UNARC SAVE *.* N ; List all files in archive SAVE with no pauses
-
- The N option may not be used in conjunction with the P (Print) or C (Check)
- options.
-
-
-
- LISTING AN ARCHIVE DIRECTORY
- ----------------------------
-
- By default, UNARC produces a detailed console listing of the component files
- in an archive. (In fact, there is no way to suppress this listing; it is
- generated during all UNARC operations.) If only the archive file name appears
- on the command line, UNARC will generate a complete directory of all component
- files in the specified archive file. Otherwise, the second command line
- parameter may be used to select a particular file to be listed (or group of
- files, if it contains the ambiguous file specification characters "*" or "?").
- If no disk drive name is provided for the second parameter, and this parameter
- specifies a group of files, the directory listing is the only output generated
- by the program.
-
- A sample directory listing is illustrated here:
-
-
- A>UNARC CODES
-
- Archive File = CODES.ARK
-
- Name Length Disk Method Ver Stored Saved Date Time CRC
- ============ ======= ==== ======== === ======= ===== ========= ====== ====
- ABLE .DOC 24320 24k Crunched 8 11777 52% 30 Apr 86 10:50a 42C0
- BRAVO .COM 17152 17k Squeezed 4 14750 14% 2 May 86 4:11p 8CBD
- CHARLIE .TXT 234 1k Packed 3 99 58% 2 May 86 4:11p 8927
- ==== ======= ==== ======= === ====
- Total 3 41706 42k 26626 36% 58A4
-
-
- This listing is equivalent to the "verbose" listing of the MS-DOS ARC program
- (with the addition of the "Disk" and "Ver" fields, which are unique to UNARC).
- The listing requires a 78-column terminal width; there is currently no "short"
- listing format.
-
- "Name" is the file name which will be generated if the file is extracted by
- UNARC on a CP/M system. (This is not necessarily the same as the name
- recorded in the archive file. Although CP/M and MS-DOS file naming
- conventions are identical, two conversions are made to guarantee file name
- validity under CP/M: Lower-case letters are converted to upper-case, and
- non-printing characters are converted to dollar signs, "$".) Archive entries
- are usually maintained (and hence listed) in alphabetic name order.
-
- "Length" is the uncompressed file length, i.e. the number of bytes the file
- will occupy if extracted to disk, exclusive of any additional length imposed
- by the CP/M file system. Note that MS-DOS permits files of arbitrary lengths
- (unlike CP/M which restricts all files to a multiple of 128 bytes).
-
- "Disk" is the actual amount of disk space required to extract the file to a
- CP/M disk, expressed as a multiple of 1K (1024) bytes. Note that this number
- is dependent on the disk data allocation block size. (CP/M permits various
- block sizes, ranging from 1K to 16K bytes. Typical sizes are 1K for single-
- density floppy disks, 2K for double-density floppies, and 4K for hard disks,
- although these values are quite system-dependent.) In the absence of an
- explicit output drive name, UNARC uses the block size of the default
- (currently "logged") disk drive (i.e. the drive which appears in the CCP
- prompt).
-
- "Method" is the compression method used, specified as "Unpacked", "Packed",
- "Squeezed", "Crunched", "Squashed", or "Unknown!". If the method "Unknown!"
- appears, it most likely indicates (if not a faulty archive file) a newer
- release of the MS-DOS ARC program that supports a new compression method (or a
- new variation of an existing method). In this case, a corresponding new
- release of UNARC will be required to extract the file.
-
- "Ver" further identifies the version of compression used. Currently, UNARC
- supports versions 1-9: unpacked files can have versions 1 or 2; packed files,
- version 3; squeezed files, version 4; crunched files, versions 5-8; and
- squashed files, version 9. The highest version number associated with each
- compression method is the one generated by the most recent release of the
- MS-DOS ARC program.
-
- "Stored" is the compressed file length, i.e. the number of bytes occupied by
- the file in the archive. (This does not include the overhead associated with
- the directory information itself, which adds an additional 29 bytes to the
- size of each component file.)
-
- "Saved" is the percentage of the original file length which was saved by
- compression; i.e., higher values indicate better compression. (The MS-DOS ARC
- documentation refers to this as the "stowage factor.") The value shown on the
- totals line applies to the archive as a whole, not including the directory
- overhead.
-
- "Date" and "Time" refer to the last file modification, as of the time it was
- added to the archive. (Date and time stamping is, of course, one of the nice
- features of MS-DOS which is lacking in standard CP/M 2.2.)
-
- "CRC" is an internal 16-bit cyclic redundancy check value which is computed
- when a file is added to an archive (expressed in hexadecimal). As a test of
- file validity, UNARC re-computes this value when it extracts a file (see
- below). Note that this value is calculated by a different method than that
- used by either of the two popular public domain programs, CRCK and CHEK. (It
- is however quite valid as a reliable error-detection mechanism.) This value
- is shown in the listing for completeness only. The value shown on the totals
- line is the 16-bit sum of all displayed CRC values. This is useful as a
- single "checksum" value for comparing entire archives. (Since the CRC values
- are computed before compression takes place, the total should be the same for
- all archives created from the same set of input files, independent of any
- particular variations in file order or compression methods.)
-
- The "Total" line is displayed only if multiple files appear in the listing,
- and it includes a count of the number of files listed.
-
-
-
- EXTRACTING FILES FROM AN ARCHIVE
- --------------------------------
-
- If the second command line parameter contains a disk drive name, UNARC will
- extract the selected file(s) from the archive to CP/M file(s) on the indicated
- disk drive. If only a drive name appears, all component files of the archive
- will be extracted. The following illustrates a sample archive directory
- listing as generated during a file extraction operation:
-
-
- A>UNARC CODES B:
-
- Archive File = CODES.ARK
- Output Drive = B:
-
- Name Length Disk Method Ver Stored Saved Date Time CRC
- ============ ======= ==== ======== === ======= ===== ========= ====== ====
- ABLE .DOC 24320 24k Crunched 8 11777 52% 30 Apr 86 10:50a 42C0
- Replace existing output file (y/n)? Y
- BRAVO .COM 17152 18k Squeezed 4 14740 14% 2 May 86 4:11p 8CBD
- Warning: Extracted file has incorrect CRC
- Warning: Extracted file has incorrect length
- Warning: Bad archive file header, bytes skipped = 10
- CHARLIE .TXT 234 2k Packed 3 99 58% 2 May 86 4:11p 8927
- ==== ======= ==== ======= === ====
- Total 3 41706 44k 26616 36% 58A4
-
-
- The above listing also illustrates several warning messages which may occur
- when extracting files from an archive.
-
- The message "Replace existing output file (y/n)?" appears if a file of the
- same name already exists on the output drive. The user must answer "Y" (or
- "y") to allow the extraction to proceed (in which case, the existing file is
- unceremoniously deleted). Any other response will cause UNARC to preserve the
- existing file, bypass the extraction operation for the current file, and
- (except for a CTRL-C response) skip to the next file to be extracted (if any).
-
- The first two warning messages illustrated above are provided as a check on
- the validity of the extracted file. These indicate that either the cyclic
- redundancy check (CRC) value computed by UNARC, or the resulting extracted
- file length, does not match the corresponding value recorded in the archive
- when the original file was added to it. The final warning message occurs if
- UNARC fails to detect the proper format for the start of a new subfile, but
- can recover by skipping a certain number of bytes in the archive file. (If
- the recovery attempt fails, UNARC aborts with the message "Invalid archive
- file format.") The appearance of any of these messages most likely indicates
- that the file data has been corrupted in some way (e.g. during modem
- transmission from a remote system).
-
- Note that if the original (i.e. MS-DOS) file length was not an exact multiple
- of 128 bytes (as required by CP/M), UNARC will pad the final record of the
- extracted file with hex "1A" (ASCII CTRL-Z) bytes. This provides the correct
- end-of-file termination for text files, according to CP/M conventions.
-
- Also, the disk space shown in the archive directory listing will be correct
- for the specified disk drive. (In the above examples, drive A: has a 1K data
- allocation block size while drive B: has a 2K block size, which accounts for
- the differences in the two listings.) In order to determine the exact disk
- space requirements in advance of a file extraction operation, the user may
- first "log into" the desired output drive (i.e. select it as the default
- drive), and run UNARC to obtain a directory listing only. (This is a
- consideration only on systems with mixed disk drive types.)
-
- A file extraction operation may be aborted at any time by entering CTRL-C from
- the console. In this case, any partial output file will remain on disk and
- should be deleted manually following the program abort. (Any existing file of
- the same name will have already been deleted, however.)
-
-
-
- TYPING OUT A FILE IN AN ARCHIVE
- -------------------------------
-
- A console typeout of the contents of a single component file in an archive may
- be requested by specifying a non-ambiguous file name (and no disk drive name)
- in the second command line parameter. For example:
-
-
- A>UNARC CODES ABLE.DOC
-
- Archive File = CODES.ARK
-
- Name Length Disk Method Ver Stored Saved Date Time CRC
- ============ ======= ==== ======== === ======= ===== ========= ====== ====
- ABLE .DOC 24320 24k Crunched 8 11777 52% 30 Apr 86 10:50a 42C0
- -------------------------------------------------------------------------------
- This is file ABLE.DOC, contained within the archive CODES.ARK. Typeout will
- proceed until the end of this file or may be aborted by CTRL-C.....
-
-
- The specified file is assumed to contain valid ASCII text data. In
- particular, all bytes are masked to seven bits, and all ASCII control
- characters are ignored except for HT (horizontal tab, which is expanded to
- blanks with assumed tab stops at every eighth column), LF, VT or FF (line
- feed, vertical tab or form feed, which generate a new typeout line), and SUB
- (CTRL-Z, which by CP/M convention indicates end-of-file and terminates the
- typeout). Note that BS (backspace) and CR (carriage return) are ignored, so
- that text will not be obscured within files which utilize these for over-
- printing (i.e. when directed to a printer).
-
- The following filetypes, which are usually associated with binary (non-text)
- data, are specifically excluded from typeout operations: COM, EXE, OBJ, OV?,
- REL, ?RL, INT, SYS, BAD, LBR, ARC, ARK, ?Q?, and ?Z?. If one of these types
- is specified, only the directory information for the requested file is listed.
-
- Note that CRC and file length checking are not performed during a typeout
- operation, as they are during extraction to a disk file.
-
-
-
- PRINTING A FILE IN AN ARCHIVE
- -----------------------------
-
- A single component file in an archive may be output directly to the printer
- (CP/M list device) by specifying a trailing "P" on the command line. The "P"
- must be the last command line character, and it must be separated from the
- second file parameter by a space. (The file parameter must specify a non-
- ambiguous file name and no disk drive name.) For example:
-
- A>UNARC CODES CHARLIE.TXT P
-
- The specified file is assumed to contain data suitable for printer output and
- is passed directly to the printer without alteration or additional formatting.
- This operation is particularly well-suited for output of binary graphics
- images on dot-matrix printers, since these can be extemely large but tend to
- compress quite well (e.g. to less than 5% of their original size). Note that
- the binary data filetypes which are excluded from typeout operations are also
- excluded from printing operations. Printing may be paused or aborted by use
- of the console CTRL-S and CTRL-C characters.
-
-
-
- CHECKING FILES IN AN ARCHIVE
- ----------------------------
-
- UNARC may be directed to extract one or more component files from an archive,
- without actually storing these as disk files, by specifying a trailing "C" on
- the command line. This operation performs file CRC and length checking, and
- it is useful for verifying correct modem data transmission of an archive. The
- "C" must be the last command line character, and it must be separated from the
- second file parameter by a space. (The file parameter must not specify a disk
- drive name, which indicates extraction to disk.) To check an entire archive,
- specify "*.*" for the second file parameter, for example:
-
- A>UNARC CODES *.* C
-
-
-
- PROGRAM OPTIONS
- ---------------
-
- UNARC provides several options which may be used to tailor the program for
- specific non-universal requirements. Many of these are intended for RCP/M
- (Remote CP/M) system operators, to allow generation of a secure version of
- UNARC which can be used by remote callers for purposes of archive directory
- listing and/or file typeout only (but not file extraction). Others are
- provided for specialized non-standard CP/M systems and need not concern the
- majority of users running CP/M 2.2, CP/M 3.0 (CP/M Plus), or ZCPR3/ZRDOS
- systems. Additional options provide user preference features (such as the
- number of screen lines between console output pauses, or the list of filetypes
- excluded from typeout operations).
-
- All of these options are described in UNARCOVL.ASM, an assembly language
- source file that can be edited and assembled to generate a HEX-format overlay
- for easy patching of the UNARC.COM or UNARCA.COM program files. Complete
- details are provided for technically-oriented users in UNARCOVL.ASM. However,
- the default options in the distributed program files are suitable for the
- majority of users with standard CP/M operating systems.
-
-
-
- PROGRAM DISTRIBUTION
- --------------------
-
- The UNARC program, its documentation, and all related files are distributed in
- archive file format (of course!). The distribution file is named UNARCxx.ARK,
- where "xx" is derived from the current version number (e.g. UNARC16.ARK for
- version 1.6). (This does not include the program source code, which is
- distributed separately.) This archive has the special characteristic that it
- is "self-unpacking." I.e., a separate copy of the UNARC.COM program file is
- NOT required to extract the component files from this archive.
-
- The procedure for extracting the distribution files is quite simple: First,
- copy or rename UNARCxx.ARK to a program file, UNARCxx.COM, on the current disk
- drive. (Note that the filename, UNARCxx, must NOT be changed.) 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
- drive).
-
- 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.
-
-
-
- AUTHOR'S NOTE
- -------------
-
- I undertook writing the UNARC program to satisfy my curiosity about software
- developments in the MS-DOS/PC-DOS world. At the time I began work on UNARC,
- the MS-DOS ARC program had been in existence for over a year and had achieved
- widespread popularity and acceptance in the 16-bit community. Unfortunately,
- the lack of a compatible equivalent for CP/M systems rendered a large amount
- of public domain software inaccessible to 8-bit users such as myself. (Note
- that 16-bit software can indeed be of interest to users of 8-bit systems, e.g.
- Pascal and C language programs.)
-
- Also, an increasing number of RCP/M systems now cater to both 8-bit and 16-bit
- users. Since the release of UNARC 1.0 (May 3, 1986), I have been encouraged
- to see that the program has found a welcome home on many such systems.
- Special thanks are due to Irv Hoff and Norman Beeler for providing archive
- file support in the KMD20 and LUX52 series of programs, respectively. With
- the increasing popularity of .ARC files on many different computer systems, I
- believe that continued such support of this compression format is both
- desirable and inevitable for CP/M systems. At the time of this writing I am
- about to release NOAH, a companion program to UNARC which will allow CP/M
- users to generate ARC-compatible files.
-
- Bob Freed
- March 27, 1987
-
-
-
- NOTICE
-
- The UNARC program and its associated documentation is the copy-
- righted property of its author -- it is NOT in the public domain.
- HOWEVER... Free use, distribution, and modification of these
- files is permitted (and encouraged), subject to the following
- conditions:
-
- (1) Such use or distribution must be for non-profit purposes only.
- (2) The author's copyright notice may not be altered or removed.
- (3) Modifications to this program or its documentation files may
- not be distributed without notification of and approval by
- the author.
- (4) The source program code may not be used, in whole or in part,
- in any other publicly-distributed or derivative work without
- similar notification and approval.
-
- No fee is requested or expected for the use and distribution of
- this program subject to the above conditions. The author reserves
- the right to modify these conditions for any future revisions of
- this program. Questions, comments, suggestions, commercial
- inquiries, and bug reports or fixes are welcomed by the author:
-
- Robert A. Freed
- 62 Miller Road
- Newton Centre, MA 02159
- Telephone (617) 332-3533
-
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-