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This has allowed other authors to fork the PAQ compression engine and add new features such as a graphical user interface or better speed (at the expense of compression ratio). Notable PAQ derivatives include: WinUDA 0.291, based on PAQ6 but faster [7] UDA 0.301, based on PAQ8I algorithm [7] KGB, based on PAQ6 [8] (beta version is based on PAQ7).
Thus, a representation that compresses the storage size of a file from 10 MB to 2 MB yields a space saving of 1 - 2/10 = 0.8, often notated as a percentage, 80%. For signals of indefinite size, such as streaming audio and video, the compression ratio is defined in terms of uncompressed and compressed data rates instead of data sizes:
Most compression programs won't be able to take advantage of this redundancy, and thus might achieve a much lower compression ratio than rzip can achieve. The intermediate interface between the two stages is made of a byte-aligned data stream of which there are two commands, a literal ("add") with length and data:
DEFLATE is a variation on LZ optimized for decompression speed and compression ratio, [7] but compression can be slow. In the mid-1980s, following work by Terry Welch, the Lempel–Ziv–Welch (LZW) algorithm rapidly became the method of choice for most general-purpose compression systems.
This leads to Deflate64 having a longer compression time, and potentially a slightly higher compression ratio, than Deflate. [7] Several free and/or open source projects support Deflate64, such as 7-Zip, [8] while others, such as zlib, do not, as a result of the proprietary nature of the procedure [9] and the very modest performance increase ...
Executable compression used to be more popular when computers were limited to the storage capacity of floppy disks, which were both slow and low capacity media, and small hard drives; it allowed the computer to store more software in the same amount of space, without the inconvenience of having to manually unpack an archive file every time the ...
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For example, if the static compression ratio is 10:1, and the dynamic compression ratio is 7.5:1, a useful value for cylinder pressure would be 7.5 1.3 × atmospheric pressure, or 13.7 bar (relative to atmospheric pressure). The two corrections for dynamic compression ratio affect cylinder pressure in opposite directions, but not in equal strength.