压缩算法(Compression algorithms)

Category of data compression algorithms

• Lossless compression algorithms
  Lossless data compression algorithms usually exploit statistical redundancy to represent data without losing any information, so that the process is reversible. Lossless compression is possible because most real-world data exhibits statistical redundancy.
• Lossy compression algorithms
  Lossy data compression is the converse of lossless data compression. In these schemes, some loss of information is acceptable. Dropping nonessential detail from the data source can save storage space. Lossy data compression schemes are designed by research on how people perceive the data in question. For example, the human eye is more sensitive to subtle variations in luminance than it is to the variations in color.

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1. tar是Linux常见的一种归档文件（原生不包括压缩功能）
2. gzip是gnu/Linux的一种压缩文件工具，算法是基于 DEFLATE，文件是gz，可以和tar组合。
3. zip是一种规范开放的压缩文件，算法不定，但主要是用 DEFLATE
4. rar的算法专有，但发行时附送解码器允许解码器再开发，编码器专有
5. 7zip和zip差不多，算法不定，主要用bzip2和lzma，而且完全开源。
6. zip和7z更像是压缩容器，因为算法不是格式固定，允许支持其他压缩算法

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1. Lossless compression algorithms
2. Lossy compression algorithms
3. Data compression