Comparison of ZIP, 7Z, TAR Archives: Guide to Compression Ratio and System Support

ZIP was released in 1989, positioned as a general-purpose file exchange format. It supports single-file compression and multi-file packaging, can be recognized directly by most programs on all platforms, and is currently the most widely used compression format.

7Z was released in 1999, designed by Igor Pavlov, and positioned for high-compression-rate archiving scenarios. It uses the LZMA2 algorithm by default, making it suitable for local storage with strict volume requirements.

TAR was released in 1979, and is the standard archiving format for Unix systems. It only handles packaging multiple files into a single file, does not natively provide compression functionality, and is positioned for file archiving in the Unix ecosystem.

ZIP uses the DEFLATE algorithm by default, and 7Z uses the LZMA2 algorithm by default. There is a quantifiable difference in their compression ratios. For text files, the DEFLATE compression ratio ranges from 40% to 60%, while the LZMA2 compression ratio ranges from 20% to 40%. This means that for the same original text volume, the output volume of 7Z is 20% to 35% smaller than that of ZIP.

For binary files, the DEFLATE compression ratio ranges from 60% to 75%, while the LZMA2 compression ratio ranges from 45% to 60%. For the same original binary volume, the output volume of 7Z is 15% to 25% smaller than that of ZIP. LZMA2 typically takes longer to compress than DEFLATE, and the gap is more pronounced at high compression levels.

TAR follows the single-responsibility design philosophy, only implementing multi-file archiving functionality and not integrating any compression algorithms. This design adapts to the working mode of the Unix system toolchain, and can be used with any external compression tool.

TGZ is a common combination of TAR paired with gzip compression. gzip uses the DEFLATE algorithm: multiple files are first packaged into a single archive via TAR, then the entire archive is compressed with gzip, resulting in a file with the .tar.gz suffix. In addition to gzip, TAR can also be used with compression tools such as xz and bzip2.

Different operating systems have different native support capabilities for the three formats, resulting in different ranges of formats that can be operated directly without third-party tools. This section summarizes the native support status of mainstream desktop systems.

Split archiving is a function that divides a single large archive into multiple small files of a specified size, to facilitate storage and transmission. Both ZIP and 7Z natively support split archiving. TAR does not support splitting natively, and requires external tools to implement this feature.

In terms of encryption and recovery records, ZIP supports traditional password encryption and is partially compatible with AES encryption. 7Z natively supports AES-256 encryption. TAR does not have built-in encryption functionality, and can be used with external encryption tools. Both ZIP and 7Z support adding recovery records to repair minor damage to archives, while TAR does not have this built-in feature.