	ACB Ver.1.08b - ARCHIVATOR FOR COMMUNICATION PURPOSES

  ACB Ver.1.08b - Associative coder of Buyanovsky is designed for
preliminary information compression in communication purposes.

The usage of the ACB algorithm (Associative Coder of Buyanovsky) ensures a
record compression coefficient. The associative coding algorithm requires
higher demands towards equipment. Decreasing sizes of archives by 10-60%
in comparison with ARJ,PKZIP,RAR justifies to the most extent increased
expenses on data compression in telecommunication tasks.

		0. WHAT IS NEW

 Overview of changes from v1.06b to v1.07a:

  - Compression speed increased.
  - Compression coefficient increased.
  - Data protection from errors added.
  - Data encryption with password added.
  - ACB now properly handles file attributes.
  - ACB now properly handles file date and time.
  - Sizes of the sources data increased. Maximum of separate
    file size is 64 Mb now.
  - ACB v1.07a archive format is not compatible with older versions.

 Overview of changes from v1.07a to v1.08a:

  - Compression speed increased.
  - Compression coefficient increased.
  - TC-mode ("taught channel") added.
  - ACB v1.08a archive format is not compatible with older versions.

 Overview of changes from v1.08a to v1.08b:

  - Little bug fixed in "taught channel" mode.
  - Little bug fixed in list contents of the protected archive.

		1. Main characteristics

 1.1. The size of archives in comparison with the archives received by
PKZIP V_2.04g is less by 10-60%. Correspondence of advantages (in comparison
to PKZIP v_2.04g) of data types is shown below:
type of files		percent
*.zip			-1  - +20 % (20% on size >= 1 Mb.)
*.exe,*.com		+10 - +25 %
*.txt,*.doc		+20 - +35 %
*.dbf,*.xls,*.mdb,*.fli	+25 - +40 %
			+35 - +60 % - on information of the same type in the
			extensive catalogue structure with a high coefficient
			of repetition (e.g. directories of contract texts)

1.2. Speed of packing/unpacking 2-7 Kbyte/sec. on i486SX-33
- 2 Kb/sec. - on weakly extra data;
- 7 Kb/sec. - on extra data;
In using Pentium-100 processor the speed increases by 5 times.

1.3. ACB allows to create multivolume archives.
In case of deficit of disk space multivolume archive is created automatically
( e.g. part of archive on disk A: part on B: remainder on C:).

1.4. ACB - does not have a possibility to add/take out one or several files
in/out of the archive - only all the data.

1.5 In creating a multivolume archive the following agreements are observed:
- 1Kb == 1024 bytes
- name of the first volume *.00b...second *.01b...eleventh *.0ab...last *.acb
- unpacking begins with *.00b .

1.6 Option: Data Protection from Errors (DPE-mode).

1.7 Option: "taught channel" (TC-mode).

1.8 Sizes of the sources data are not boundary. Maximum of separate file size
is 64 Mb.

		2. Technical requirements

For work of ACB the following technical means are necessary:
minimum - i486SX-33, RAM 8 Mb;
recommended - Pentium-100 RAM 8 Mb;
Operational systems MS-DOS 5.0+, WINDOWS_3.1+(win32s) or WINDOWS_95.
Usage of archives in the background mode under WINDOWS is effective.
Note: For the work of the algorithm it necessary to have 7.6 Mb of free RAM
(Conv.+Ext.), or if less free memory, the program can be started under
WINDOWS_3.1(win32s) or WINDOWS_95, as the program uses its swapping, that
results in slower packing/unpacking on big sizes of data (with 3Mb free RAM
slowing down can be noticed from 300 Kb of nonpacked data).

		3. Development of ACB

3.0. The ACB algorithm is a stream algorithm which can be used in digital
telecommunication networks. The Lempel-Ziv algorithm originally is also a
stream one, but the compression coefficient demonstrated by archivators which
use it, is achieved by adjusting the algorithm to a concrete type of data at
the expense of preliminary overview of the latter data, that is why these
modifications are not stream ones, the original Lempel-Ziv algorithm
demonstrates less compression coefficient. Besides, the ACB compression
coefficient grows asymptotically with the growth of associative frame,
but for LZ exists an optimal size a dictionary for every type of data, the
compression coefficient shows worse results in case of bigger sizes.
Complexity of the ACB algorithm realized in ACB.EXE Ver.1.08b :
Time  - O(N)=N*(Log2(N)+52) - estimation from above (for data "white noise");
RAM (byte) - S(N)=N*9.125+13000;
where N - size of associative frame in bytes (820 Kb).
Size of the ACB algorithm code (packing+unpacking) - 7 Kb.
Algorithm of the packing/unpacking is symmetric.

3.1. The usage of the ACB algorithm in the mode "taught channel" - is of
great interest - maximum compression of little amount of information
transmitted by communication lines can be achieved by using all the
information transmitted earlier by this information channel, besides reliable
cryptographing is achieved - not knowing all the background of the channel,
decoding is impossible in principle. The hardware support of the algorithm
in the mode of the taught channel will allow to use advantages of the
associative coding algorithm to the most extent. The mode "taught channel"
will allow to decrease the size of the code by 30-80% of the common mode
when compression is made without taking into account the channel background.
The less the size of transmitted data in the current session related the size
of the data transmitted in the previous sessions, the more advantage in the
"taught channel" mode.

3.2  By desire of the client the algorithm can be modified - that
also is guaranteed by reliable cryptographing, where the algorithm
itself acts as a key.

3.3  The ideas put in the ACB algorithm can be used in other applied
tasks: compression of AUDI-VIDEO information, prognosis of dynamic
series, images recognition, correcting codes (discovery and correction
of errors in data), building effective cache functions and etc.

3.4 The Author of ACB is interested in financing these designs.

		4. Terms of using ACB.EXE Ver.1.08b

- This program is FREEWARE. Permission is granted to any individual or
  institution to use, copy, or redistribute this executable as long as
  it is not modified.
- This program is distributed with NO WARRANTY of any kind, either
  expressed or implied.
- 49% of the sales of the license will be given to the person who has
  funded the licensing of the associative coding algorithm.

  This version of ACB is not yet a finished product, but I hope that
  someone finds it usefull even in it's current form.

ACB 1.08b (C) 1994-95 Buyanovsky Georgii & Nuserov Timur 6.30.1995
480063 CIS, Republic of Kazakhstan, Almaty, Zhetisu-2,56-9, ph. 7_3272_271317
