On Wed, 2008-05-21 at 18:47 +0300, Dimitrios Apostolou wrote:
Hi,
On Tue, 2008-05-20 at 10:14 +0200, Jan de Groot wrote:
Pacman itself is ready for .tar.bz2 package files. The whole issue with .bz2 files is that compression and decompression times increase a lot without giving the same amount of size reduction back. We've done some recent tests with LZMA, which compresses just as good as bzip2 at the lowest compression rate, but does it at the same speed as gzip.
About LZMA I should add that when using higher (actually the default) compression rate, compression is much better than bzip2 but takes more time/memory. Decompression however, which is what really matters in a packaging format, is kept fast and lightweight.
What's the memory usage when unzipping an LZMA file? Is it much higher than the needs of gzip? We already have problems supporting low-memory systems with our installer, adding a compression algorithm that eats more memory will cause even more problems for these systems.
The downside is that LZMA is not supported by libarchive, and won't be supported officially either, because libarchive is BSD licensed and LZMA is GPL licensed.
Can't this problem be circumvented by spawning the lzma command line utility, and piping all data to it? I understand that this perhaps negates the purpose of libarchive, but the overhead should be small.
libarchive can't spawn external commands to unzip archive files. bsdtar can, but as pacman is a binary with libarchive integrated, I don't see this happening.