Category : Utilities for DOS and Windows Machines
Archive   : LIMIT12.ZIP
Filename : LIMIT.DOC

20 July 93

LIMIT version 1.0

Data Compression Archive utility
-------------------------------------------------------------------------------

LIMIT is a fast and compact data compressor/archiver. The compression &
decompression routines have been written entirely in 80286 assembly, so it
runs faster than many other archivers. LIMIT also compresses better than
other archivers; it uses a compression method based on 32K sliding window
dictionary plus huffman encoding, similar to LHA/PKZIP/ARJ, but with some
improvments.

LIMIT is free! You may distribute freely, as long as the program is not
modified in any way. You are encouraged to contribute $20/- to the
programmer if you like this archiver.



1. Files included in LIMIT 1.0
===============================

LIMIT.EXE the executable file
LIMIT.DOC LIMIT documentation


2. System requirements
===============================

80286 (PC/AT) and above
Minimum conventional memory:
270k for updating/creating archives
170k for extracting/testing archives


3. How to use LIMIT
===============================

Usage:
LIMIT command [options] archive[.LIM] [files] [@listfile] [#commentfile]

The special prefix '#' specifies a comment file to be added/deleted to/from
archive. Prefix '@' species a list file to be included.

A list file is a text file consisting of file specfications separating by
space/tab/newline.


4. Commands
===============================

a[dd] add files to archive, create one if necessary

c[reate] create new archive
(delete previous archive of the same name)

del delete files (or comment) in archive+

e[xtract] extract files in archive

h[elp] display help information

i[nfo] archive info
shows summary of archive

l[ist] list specified files in archive

rd remove directories
(directories must be empty.)

t[est] test files in archive by perform CRC checks



5. options: (use - or / prefix)
===============================

-x exclude files from the file list
a list file may be specified: -x@listfile

[commands: a,c,del,e,rd,t]

-d add/extract directory
adding files: specifies the path to add files to
extracting files: specifies the path to extract to

[commands: a,c,e]

-n add/extract new files only

[commands: a,c,e]

-r recurse sub-directories

[commands: a,c]

-s recurse and store/extract partial paths
files are added/extracted to their partial paths

default: all files are added to root directory,
and extracted to the current directory

[commands: a,c,e]

-p store/extract full original paths
files are added/extracted to their original paths

default: all files are added to root directory,
and extracted to the current directory

[commands: a,c,e]

-w[h|s] include hidden or system files
default: hidden/system files are not added to archive

[commands: a,c]

-es extract to screen
default: extract to file

[command: e]

-y yes to all queries:
1) del command: "delete all files?"
2) e command: "overwrite file?"

-m[0|1|s|x] compression methods:
-m0: store only
-m1: normal compression (default)
-ms: fast compression
-mx: maximum compression

[commands: a,c]

6. Examples
===============================

LIMIT a test *.c add all *.c files to test.lim archive

LIMIT a test /dabc add all (default) files to directory "abc" in test.lim

LIMIT t test test (using CRC checks) the archive test.lim

LIMIT l test *.asm list all *.asm files in test.lim

LIMIT l test \abc\* list all files in \abc directory in test.lim

LIMIT e test extract all files in test.lim to current directory

LIMIT e test /n extract all new files in test.lim to current directory

LIMIT e test /y extract all files (overwrite, no query) to current dir

LIMIT e test *.c /dc:\ extract all *.c files to C:\

LIMIT del test *.h delete all *.h files

LIMIT rd test \temp remove \temp directory in archive test.lim

LIMIT i * shows information of all archives in the current dir

LIMIT a -mx test add all files to test.lim, with maximum compression

LIMIT a test /whs add all files (including hidden & system) to test.lim

LIMIT a test \abc\*.* /r /p add files, recurse sub-dirs and store full
paths, i.e. include directory \abc
LIMIT a test \abc\*.* /s add files, recurse sub-dirs and store new
paths (excluding directory \abc)
LIMTI a test \abc\*.* /r add files, recurse sub-dirs, store all files
in root directory
LIMIT a test \abc\*.* /p add files, store full paths

LIMTI e test /p extract all files and subdirectories into
original paths

7. Setting the environment string LIMIT
========================================
Options that are included in the environment string LIMIT are automatically
included whenver LIMIT is run. To set the environment string, type

> set LIMIT = /mx /n

This tells LIMIT to use maximum compression and add/extract newer files only.
However, options specified in the command line override those options in
the LIMIT environment string.


8. Compression method
===============================
LIMIT employs a LHA/PKZIP/ARJ-similar kind of sliding dictionary plus huffman
encoding, with some minor enhancements.

A compression index controls the extent to which strings are searched in the
dictionary. The index for each compression option is as follows:

/ms (fastest) compression: 30
/m1 (default) compression: 300
/mx (maximum) compression: 3000

However, there are files where a smaller index yields better compression.
You may fine-tune the compression by controlling the index, using option
/c.
e.g. LIMIT a /c1000 archive *.*


9. Bugs/Comments
===============================
No program is free of bugs, so report any bugs or comments or suggestions to
the programmer.


10. Contributions, please!
===============================
LIMIT is the product of thousands of programming hours. If you like this
program, please contribute some money ($20 would be great!) to the programmer
as a token of encouragement.


-------------------------------------------------------------------------------

J Y LIM
[email protected]
226, Linden Ave. Apt 1.
Ithaca, NY 14850
USA