The compression is also lossless, but the compression is not transparent to applications. The file compression and decompression libraries take an existing file or files and produce a file or files that are compressed versions of the originals. Obtaining the Size of a Compressed Fileįile Compression and Decompression Libraries.The following topics identify the NTFS file system file compression: If you compress a file that is larger than 30 gigabytes, the compression may not succeed. However, these files cannot be copied to another file system. Therefore, applications that open a compressed file can operate on it as if it were not compressed. The compressed bytes of the file are not accessible to applications they see only the uncompressed data. This means it can be used without requiring changes to existing applications. On the NTFS file system, compression is performed transparently.
Another compression algorithm, known as the Lempel-Ziv algorithm, converts variable-length strings into fixed-length codes that consume less space than the original strings. Another compression algorithm, called run-length encoding, generates a two-part value for repeated characters: the first part specifies the number of times the character is repeated, and the second part identifies the character.
#Compress file code#
For example, the Huffman encoding algorithm assigns a code to characters in a file based on how frequently those characters occur. Data compression creates a compressed version of a file by minimizing this redundant data.Įach type of data-compression algorithm minimizes redundant data in a unique manner. In a text file, redundant data can be frequently occurring characters, such as the space character, or common vowels, such as the letters e and a it can also be frequently occurring character strings. This is a lossless compression algorithm, which means that no data is lost when compressing and decompressing the file, as opposed to lossy compression algorithms such as JPEG, where some data is lost each time data compression and decompression occur.ĭata compression reduces the size of a file by minimizing redundant data. The file compression algorithm used by the NTFS file system is Lempel-Ziv compression. The NTFS file system volumes support file compression on an individual file basis.
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