isa-l VS indexed_gzip

For using accelerators (QAT, I assume, because the article is about this) from the CLI, then QATzip[3] comes with a command line tool qatzip which can be used as described in the project ReadMe. I didn't test it, though, as I have no QAT-enabled device.

[1] https://github.com/intel/isa-l/tree/master/igzip

Ex 1: https://github.com/intel/isa-l/blob/master/README.md

Examples: - Someone I know created machine-optimized library in c and asm to accelerate compression, erasure coding, and encryption on Intel Xeon CPUs (https://github.com/intel/isa-l) which runs those ops WAY faster than the standard linux libraries. - My friend is making a retro SEGA genesis game using a C and asm dev kit (https://github.com/Stephane-D/SGDK)

igzip (https://github.com/intel/isa-l) is much faster than gzip or pigz when it comes to decompression, 2-3x in my experience. There is also a Python module (isal) that provides a GzipFile-like wrapper class, for an easy speed-up of Python scripts that read gzipped files.

However, it only supports up to level 3 when compressing data, so it can't be used as a drop-in replacement for gzip. You also need to make sure to use the latest version if you are going to use it in the context of bioinformatics, since older versions choke on concatenated gzip files common in that field.

Pragzip actually decompress in parallel and also access at random. I did a Show HN here: https://news.ycombinator.com/item?id=32366959

indexed_gzip https://github.com/pauldmccarthy/indexed_gzip can also do random access but is not parallel.

Both have to do a linear scan first though. The implementations however can do the linear scan on-demand, i.e., they scan only as far as needed.

bzip2 works very well with this approach. xz only works with this approach when compressed with multiple blocks. Similar is true for zstd.

For zstd, there also exists a seekable variant, which stores the block index at the end as metadata to avoid the linear scan. indexed_zstd offers random access to those files https://github.com/martinellimarco/indexed_zstd

I wrote pragzip and also combined all of the other random access compression backends in ratarmount to offer random access to TAR files that is magnitudes faster than archivemount: https://github.com/mxmlnkn/ratarmount

The pieces are there. https://github.com/devsnd/tarindexer/blob/master/tarindexer.py is a prototype of indexing and seeking a tar file in python. https://github.com/pauldmccarthy/indexed_gzip allows indexing and seeking a gzip file. If those pieces of code were combined it could give you efficient targeted file extraction, but you'd need to find a coder with enough time and motivation to fuss with it.