7 Zip 9.21 Full Version

7 Zip 9.21 Full Version Free Download

Description:

• Formats

By default, 7-Zip creates 7z format archives with a .7z file extension. Each archive can contain multiple directories and files. As a container format, security or size reduction are achieved using a stacked combination of filters. These can consist of pre-processors, compression algorithms, and encryption filters.
The core .7z compression uses a variety of algorithms, the most common of which are bzip2, LZMA2, and LZMA. Developed by Pavlov, LZMA is a relatively new system, making its debut as part of the 7z format. LZMA consists of a large LZ-based sliding dictionary up to 4 GB in size, backed by a range coder.
The native 7z file format is open and modular. All filenames are stored as Unicode.
TopTenReviews found that the 7z compression is at least 17% better than ZIP, and 7-Zip's own site reports that while compression ratio results are very dependent upon the data used for the tests, "usually, 7-Zip compresses to 7z format 30-70% better than to zip format, and 7-Zip compresses to zip format 2-10% better than most of other zip compatible programs."
The official 7z file format specification is distributed with the program's source code, in the 'doc' subdirectory.

•  Features

7-Zip supports:

• The 256-bit AES cipher. Encryption can be enabled for both files and the 7z directory structure. When the directory structure is encrypted, users are required to supply a password to see the filenames contained within the archive. WinZip-developed zip file AES encryption standard is also available in 7-Zip to encrypt ZIP archives with AES 256-bit, but it does not offer filename encryption as in 7z archives.
• Volumes of dynamically variable sizes, allowing use for backups on removable media such as writable CDs and DVDs.
• Usability as a basic orthodox file manager when used in 2-panel mode.
• Multiple-core CPU threading settings can be configured.
• The ability to attempt to open EXE files as archives, allowing the decompression of data from inside many "Setup" or "Installer" or "Extract" type programs without having to launch them.
• The ability to unpack archives with corrupted filenames, renaming the files as required.
• The ability to create self-extracting single- (but not multi-) volume archives.
• Command-line interface.

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