7Z, 7z compressed archive file (.7z)
The 7Z Archive file format
Released in 1999 (developed by Igor Pavlov) using the 7-Zip program, the 7Z file extension can support various types of data compression, encryption, and pre-processing algorithms. It is considered “future proof” since it has been able to work with various new archiving programs. Currently, 7Z is an open source extension available to the public domain since 2008. Compression methods which support 7Z include LZMA, PPMD, BCJ, BZip2, and Deflate. The open architecture allows compression, conversion, and encryption methods to be stacked. This type is used for the storage and sending/receiving of especially large files or groups of files. Want to use this versatile archive file yourself? Check it out, you can convert to 7z here.
Technical details of 7Z files
Files up to 16 billion GB (16 exbibytes) can be compressed using the 7-Zip system with its high compression ratios, solid compressing, and strong AES-256 encryption. Dictionary sizes are capable of being up to 4 GB. Compression speed is 1 MB/s and decompression is accomplished at up to 20 MB/s (both on a 2 GHz CPU). The code size for decompressing is roughly 5 KB. 7Z files can support multi-part archives, which can then be combined later. The 7Z format does not support the storage of filesystem permissions (like those from UNIX or NTFG ACLs) so the use of 7Z for backing up and archiving can be a problem though there are ways to work around that.