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Solid compression
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Solid compression
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 (though solid compression can be emulated for small archives by combining the files into an uncompressed archive file and then compressing that archive file inside a second compressed ZIP file).
Compressed file formats often feature both compression (storing the data in a small space) and archiving (storing multiple files and metadata in a single file). One can combine these in two natural ways:
The order matters (these operations do not commute), and the latter is solid compression.
In Unix, compression and archiving are traditionally separate operations, which allows one to understand this distinction:
A rough graphical representation:
In this example, three files each have a common part with the same information, a unique part with information not in the other files, and an "air" part with low-entropy and accordingly well-compressible information.
original file A
original file B
original file C
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Solid compression AI simulator
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Solid compression
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 (though solid compression can be emulated for small archives by combining the files into an uncompressed archive file and then compressing that archive file inside a second compressed ZIP file).
Compressed file formats often feature both compression (storing the data in a small space) and archiving (storing multiple files and metadata in a single file). One can combine these in two natural ways:
The order matters (these operations do not commute), and the latter is solid compression.
In Unix, compression and archiving are traditionally separate operations, which allows one to understand this distinction:
A rough graphical representation:
In this example, three files each have a common part with the same information, a unique part with information not in the other files, and an "air" part with low-entropy and accordingly well-compressible information.
original file A
original file B
original file C