7Z is an open source parent free compressed archive file format designed by Igor Pavlov and released in conjunction with the 7-Zip archive program on 1999-07-19. The format supports multiple lossless compression algorithms, spans multiple files at once, preserves directory structure in Unicode, multiple encryption algorithms, and a few other features. Because the format's dictionary spans multiple files, it results in noticeably smaller archives than older formats like ZIP or ARJ, and, because it uses a more powerful compression algorithm, it compresses data better than even proprietary formats like RAR or ACE.
The format supports the following compression algorithms: LZMA, LZMA2, Bzip2, PPMd, and DEFLATE, and the following encryption algorithms: AES-256 and ZipCrypto.
Although it seems some competition from RAR, 7Z has become the standard compression format for large Internet archives. Though ZIP still remains more popular in general.
In my quest to always find a superior format, I moved from ZIP to RAR, but, when I discovered that 7Z not only had all the features of RAR, but was also free and compressed better, I quickly adopted it. I use the format for all my personal archiving and only use ZIP when I suspect the person I'll be sharing my files with won't have 7-Zip installed. Although 7Z is not the best possible compression format on the market, it is close, and has a very simple UI through 7-Zip which I prefer over other compression programs, so, I continue to use it.
|7-Zip||Linux, Windows||Free, Open||Compress, Decompress, Edit||Native 7Z archiver.|
|PeaZip||BSD, Linux, Windows||Free, Open||Compress, Decompress, Edit||Not recommended. Poor UI.|
|WinRAR||Windows||Crippleware||Decompress||Not recommended. Can't create.|
|WinZip||Macintosh, Windows||Crippleware||Decompress||Not recommended. Can't create.|