lrzip/WHATS-NEW

lrzip-0.571

A new build configuration system.
Avoid spurious errors on failing to mmap a file.
Fee space will now be checked to ensure there is enough room for the
compressed or decompressed file and lrzip will abort unless the -f option is
passed to it.
The extra little chunk at the end of every large file should now be fixed.
The file lzma.txt now has unix end-of-lines.
There will be a more accurate summary of what compression window will be used
when lrzip is invoked with STDIN/STDOUT.
STDIN will now be able to show estimated time to completion and percentage
complete once lrzip knows how much file is left.
Temporary files are much less likely to be left lying around.
Less temporary file space will be used when decompressing to stdout.

lrzip-0.570

Multi-threaded performance has been improved with a significant speed-up on
both compression and decompression. New benchmark results have been added to
the README.benchmarks file.
Visual output has been further improved, with an updated help menu and no
unrelated system errors on failure.
lrzip.conf supports the newer options available.
TMP environment is now respected when using temporary files and TMPDIR can be
set in lrzip.conf.
LRZIP=NOCONFIG environment variable setting can be used to bypass lrzip.conf.
The -M option has been removed as the -U option achieves more and has
understandable semantics.
Memory usage should be very tightly controlled on compression now by default,
using the most possible without running out of ram.
Temporary files generated when doing -t from stdin will no longer be left lying
around.
lrzip will no longer stupidly sit waiting to read from stdin/stdout when called
from a terminal without other arguments.
Executable size will be slightly smaller due to stripping symbols by default
now.
The -T option no longer takes an argument. It simply denotes that lzo testing
should be disabled.
Verbose added to -i now prints a lot more information about an lrzip archive.

lrzip-0.560

Implemented OSX multi-threading by converting all semaphores to pthread_mutexes.
Converted the integrity checking to also use md5 hash checking. As a bonus it
is still backwardly compatible by still storing the crc value, and yet is
faster on large files than the old one. On decompression it detects whether
the md5 value has been stored and chooses what integrity checking to use.
Implemented the -H feature which shows the md5 hash value on compression and
decompression. It is also shown in max verbose mode.
Added information about what integrity testing will be used in verbose mode,
and with the -i option.
Added the -c option which will perform a hash check on the file generated on
disk on decompression, comparing it to that from the archive to validate the
decompressed file.
Modified lrzip to delete broken or damaged files when lrzip is interrupted or
the file generated fails an integrity test.
Added the -k keep option to keep broken or damaged files.
Case reports of corruption have been confirmed to NOT BE DUE TO LRZIP.

lrzip-0.552

Fixed a potential silent corruption bug on decompression.
Fixed compilation on freebsd.
Fixed failures on incompressible blocks with bzip2 or gzip.
Fixed osx failing to work. It does not support threaded compression or
decompression but should work again.

lrzip-0.551

Compressing from stdin should be unbroken again.
Compression values returned at the end of stdin work.
lzma failing to compress a block will not cause a failure.

lrzip-0.550

Speed up compression on large files that take more than one pass by overlapping
work on successive streams, thus using multiple CPUs better.
Fix for failures to decompress large files. Decompression will be slightly
slower but more reliable.
Faster lzma compression by default, less prone to memory failures, but at slight
compression cost.
Recover from multithreaded failures by serialising work that there isn't enough
ram to do in parallel.
Revert the "smooth out spacing" change in 0.544 as it slowed things down instead
of speeding them up.
Larger compression windows are back for 32 bits now that memory usage is kept
under better control.
Fixed some memory allocation issues which may have been causing subtle bugs.

lrzip-0.544

Hopefully a fix for corrupt decompression on large files with multiple stream 0
entries.
Fix for use under uclibc.
Fix for memory allocation errors on large files on 32 bits.
Smooth out spacing of compression threads making better use of CPU on compress
and decompress.
Fix for using -U on ultra-small files.
Use bzip2 on blocks that lzma fails to compress to make sure they are still
compressed.

lrzip-0.543

A fix for when large files being decompressed fail with multithreaded
decompression.
Slight speedup on multithreaded workloads by decreasing the nice value of the
main process compared to the back end threads as it tends to be the rate
limiting component.
Fixed lzma compression windows being set way too small by default.

lrzip-0.542

Lrzip will now try to select sane defaults for memory usage in cases where the
virtual memory heavily overcommits (eg. Linux) as this seriously slows down
compression.
For compression windows larger than 2/3 ram, lrzip will now use a sliding mmap
buffer for better performance.
The progress output is more informative in max verbose mode, and will no longer
do more passes than it estimates.
32 bit machines should be able to use slightly larger windows.
The sliding mmap not working on 2nd pass onwards has been fixed which should
speed up the slowdown of death.

lrzip-0.540

MASSIVE MULTITHREADING on the decompression phase. Provided there are enough
chunks of data in the archived file, lrzip will use as many threads as there
are CPUs for the backend decompression. Much like the multithreading on the
compression side, it makes the slower compression algorithms speed up the most.
Fixed output from being scrambled and consuming a lot of CPU time on threaded
zpaq compression.
Further fixes to ensure window sizes work on 32 bit machines.
Be more careful about testing for how much ram lrzip can use.
Minor build warning fixes.
Minor tweaks to screen output.
Updated benchmarks.

lrzip-0.530

MASSIVE MULTITHREADING on the compression phase. Lrzip will now use as many
threads as you have CPU cores for the back end compression, and even continue
doing the rzip preprocessing stage as long as it can which the other threads
continue. This makes the slower compression algorithms (lzma and zpaq) much
faster on multicore machines, to the point of making zpaq compression almost
as fast as single threaded lzma compression.
-p option added to allow you to specify number of processors to override the
built-in test, or if you wish to disable threading.
-P option to not set permissions has now been removed since failing to set
permissions is only a warning now and not a failure.
Further improvements to the progress output.
Updated benchmarks and docs.

lrzip-0.520

Just changed version numbering back to 2 point.

lrzip-0.5.2

Fixed the Darwin build again.
Fix the corner case of big ram usage on 32 bit zpaq failing due to the
compression window not being limited by limiting zpaq to 600MB windows on 32
bits as well.
Some previous failures now only induce warnings.
Improved progress output.

lrzip-0.5.1

Fixed the build on Darwin.
Rewrote the rzip compression phase to make it possible to use unlimited sized
windows now, not limited by ram. Unfortunately it gets progressively slower in
this mode the bigger the file gets but you can compress a file of any size as
one big compression window with it using the new -U option. Suggest you try
the new improved -M mode first or in combination. See the docs for more
information.
Changed the memory selection system to simply find the largest reasonable sized
window and use that by default instead of guessing the window size.
Setting -M now only affects the window size, trying to find the largest
unreasonably sized window that will still work.
The default compression level is now 9 and affects the rzip compression stage
as well as the backend compression.
Fixed some potential failures during compression.
Improved screen output with more reporting in verbose mode, and chunk size
percentage update.
Fixed file size reporting on compressed files generated from stdin.
Changed to 3 point releases in case we get more than 9 subversions ;)

lrzip-0.50

Rewrote the file format to be up to 5% more compact and slightly faster.
Made the memory initialisation much more robust, with attempted fallback
to still work even when initial settings fail.
Updated a lot of the stdin code.
The most common scenario of compression from stdin now works without
temporary files.
Lots more meaningful warnings if failure occurs.
May be able to decompress files on 32 bit machines that were compressed on 64
bit machines with >2GB windows now if there is enough ram.

lrzip-0.46

Added lrzuntar which works the same as lrztar -d.

Con Kolivas
May 2010

lrzip-0.45

Added docs for lrztar and lrunzip.
Added distclean and maintainer-clean make targets.
Created git repo: http://github.com/ckolivas/lrzip

Con Kolivas
March 2010

lrzip-0.44

Added an lrztar wrapper to compress / decompress whole directories (finally).
Added -i option to give information about a compressed file.

lrzip-0.43

Darwin support updated. Should build on OSX v10.5+
Finally, stdin/stdout support.
Test archive integrity support.
ZPAQ support in config files.

lrzip-0.42

ZPAQ compression update now shows which rzip stream it's currently compressing
making the update more useful. It also doesn't update unnecessarily with every
byte compressed which was slowing it down a LOT.

lrzip-0.41

ZPAQ compression backend! ZPAQ is from the family of "paq" compressors that
have some of the best compression ratios around, but at the cost of extremely
long compression and equally long decompression times. This can be enabled
with the -z option and makes lrzip archives made with this not backwardly
compatible.

lrzip-0.40

Compression windows should be limited by available ram now on 64bit. The limit
on 32bit is still 2GB.
The compression advantages on large files on 64bit machines with large ram
should be substantially better.
The file format is no longer compatible with earlier versions of lrzip.
Support for decompressing older formats is present, but all new files will
be generated in the new format.
Minor speedups.
Decompression should no longer stall at 4GB boundaries for extended periods
making decompression much faster on files >4GB in size.
Documentation and benchmark updates galore.

lrzip-0.31

The window size limit is now 2GB on both 32bit and 64bit. While it appears to be
smaller than the old windows, only 900MB was being used on .30 even though it
claimed to use more. This can cause huge improvements in the compression of very
large files. Flushing of data to disk between compression windows was
implemented to minimise disk thrashing of read vs write.

Con Kolivas
November 2009

lrzip-0.30

-P option to not set permissions on output files allowing you to write to
braindead filesystems (eg fat32).
Probably other weird and wonderful bugs have been introduced.

Con Kolivas
November 2009

lrzip-0.24 has updated functionality

FEATURE ENHANCEMENTS
lrzip.conf file may be used to set default parameters.
Omit conf using environment: LRZIP=NOCONFIG lrzip.....
LRZIP environment variable may be used in the future
to store certain types of parameters.

LZMA SDK has been upgraded to version 4.63. This
version fixes some problems certain users observed,
and is much simpler using a C-only wrapper
interface.

lrzip now is able to compute an ETA for completion.
In order to do this, the file must be larger than
one compression window in size. That is, is the
compression window is 500MB, and the file is 1GB,
then after the first pass, an ETA will be computed.
If the file is smaller, then no estimate can be made.

lrzip is now able to compute MB/s transfer speeds
for both compression and decompression.

CLEANUPS
Some file cleanups have been done.

Peter Hyman
January 2009
pete@peterhyman.com

lrzip-0.22 update
FEATURE ENHANCEMENTS

-g option. Now supports gzip compression. Very fast!
Expanded dictionary buffer size in lzma compressor.
Variable, expanded dictionary size buffer in both lzma
 compressor and decompressor.
Improved output during compression when using -vv.
Multi-threading supprt when using multiple processors
 or dual core processors when using lzma compression.
 This results in a nearly 2x speed improvement.
Assembler module support to speed up CRC checking.
Improvements in autotools usage, system detection
 and Makefile enhancements.
Lrzip now has a timer that will print total time
 at the end of a compression or decompression if
 -q command line option is not used.

BUG FIX!!!

Even though lrzip uses a compression threshold to
prevent the lzma compressor from getting data that
may not be compressible, there was still a possibility
that lrzip could hang. This was because a data chunk
could contain an uncompressible segment and if the
lzma compressor got it, it would hang.

THANKS TO LASSE COLLIN for uncovering the error in
the lzma wrapper code that was causing the hangup.

January 2008
Peter Hyman
pete@peterhyman.com