What are the trade-offs between speed and compression ratio for different compression tools?

1 What is compression ratio?

Compression ratio is a measure of how much a tool reduces the size of the original data. It is calculated by dividing the uncompressed size by the compressed size. For example, if a tool compresses a 100 MB file to 50 MB, the compression ratio is 2:1. A higher compression ratio means more space savings, but it may also require more time and resources to compress and decompress.

3 How does tar work?

tar is not a compression tool, but a file archiver. It combines multiple files or directories into a single file, called a tarball. tar does not reduce the size of the data, but it makes it easier to store and transfer. To compress a tarball, you need to use another tool, such as gzip, bzip2, or xz. You can also use the -z, -j, or -J options of tar to automatically compress the tarball with the corresponding tool.

4 How does gzip work?

gzip is a widely used compression tool that uses the DEFLATE algorithm. It compresses each file individually, and adds a .gz extension to the file name. gzip offers a good balance between speed and compression ratio, and is compatible with many platforms and programs. However, gzip does not support multi-threading or parallel processing, which means it cannot take advantage of multiple CPU cores or threads.

5 How does bzip2 work?

bzip2 is another compression tool that uses the Burrows-Wheeler Transform and Huffman coding algorithms. It compresses each file individually, and adds a .bz2 extension to the file name. bzip2 typically achieves a higher compression ratio than gzip, especially for text files, but it is also slower and more CPU-intensive. bzip2 supports multi-threading with the -p option, but it is still limited by the single-threaded nature of the compression algorithm.

6 How does xz work?

xz is a newer compression tool that uses the LZMA2 algorithm. It compresses each file individually, and adds a .xz extension to the file name. xz can achieve the highest compression ratio among the four tools, especially for binary files, but it is also the slowest and most memory-intensive. xz supports multi-threading with the -T option, and can adjust the compression level and algorithm with the -e and -9 options.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?