In computing, solid compression is a method for data compression of multiple files, wherein all the uncompressed files are concatenated and treated as a single data block. Such an archive is called a solid archive. It is used natively in the 7z and RAR formats, as well as indirectly in tar-based formats such as .tar.gz and .tar.bz2. By contrast, the ZIP format is not solid because it stores separately compressed files.
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