pcompress/bsc/README

Introduction:
-------------

This file is a part of bsc and/or libbsc, a program and a library for
lossless, block-sorting data compression.

bsc is a high performance file compressor based on lossless,
block-sorting data compression algorithms.

libbsc is a library based on bsc, it uses the same algorithms
as bsc and enables you to compress memory blocks.

Copyright (c) 2009-2012 Ilya Grebnov <ilya.grebnov@gmail.com>

See file AUTHORS for a full list of contributors.

See the bsc and libbsc web site:
  http://libbsc.com/ for more information.

Software License:
-----------------

The bsc and libbsc is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

The bsc and libbsc is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the bsc and libbsc. If not, see http://www.gnu.org/licenses/.

Please see the files COPYING and COPYING.LIB for full copyright information.


Memory usage:
-------------

bsc compresses large files in blocks. Multiple blocks can be processed in
parallel on multiple-core CPU. At decompression time, the block size used
for compression is read from the header of the compressed file. The block
size and number of blocks processed in parallel affects both the compression
ratio achieved, and the amount of memory needed for compression and decompression.
Compression and decompression requirements are the same and in bytes, can
be estimated as 16Mb + 5 x block size x number of blocks processed in parallel.

GPU memory usage for NVIDIA CUDA technology is different from CPU memory usage
and can be estimated as 20 x block size.


NVIDIA GPU acceleration:
------------------------

1. libbsc uses NVIDIA CUDA technology, resulting in a performance boost on computers
with NVIDIA GPU of compute capability 1.1 or higher. Lists of supported GPUs
can be found on the NVIDIA website http://developer.nvidia.com/cuda-gpus.
You also need to install latest graphics drivers that support CUDA.

2. Individual kernels are limited to a 2-second runtime by Windows. Kernels that run for
longer than 2 seconds will trigger the Timeout Detection and Recovery (TDR) mechanism.
Detailed information on disabling the Windows TDR is available at:
http://msdn.microsoft.com/en-us/windows/hardware/gg487368.aspx#E2


Sort Transform:
---------------

Sort Transform is patented by Michael Schindler under US patent 6,199,064.
However for research purposes this algorithm is included in this software.
So if you are of the type who should worry about this (making money) worry away.
The author shall have no liability with respect to the infringement of
copyrights, trade secrets or any patents by this software. In no event will
the author be liable for any lost revenue or profits or other special,
indirect and consequential damages.

Sort Transform is disabled by default and can be enabled by defining the
preprocessor macro LIBBSC_SORT_TRANSFORM_SUPPORT at compile time.


Back 40 Computing:
------------------

The Back 40 Computing project is a collection of fast, efficient GPU
primitives. This project implements a very fast, efficient radix sorting
method for CUDA-capable devices. libbsc uses the Back 40 Computing
primitives for constructing Sort Transform for CUDA-capable devices.

The Back 40 Computing copyright is as follows:

Copyright 2010-2011 Duane Merrill

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

See also the Back 40 Computing web site:
  http://code.google.com/p/back40computing/ for more information.


libdivsufsort:
--------------

The libdivsufsort project provides a fast, lightweight, and robust
C API library to construct the suffix array and the Burrows-Wheeler
transformed string for any input string of a constant-size alphabet.
libbsc uses libdivsufsort for constructing Burrows-Wheeler transform.

The libdivsufsort copyright is as follows:

Copyright (c) 2003-2008 Yuta Mori All Rights Reserved.

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

See also the libdivsufsort web site:
  http://libdivsufsort.googlecode.com/ for more information.