TAR.7Z to RAR Converter

A TAR.7Z file is a compound archive that first encapsulates files into a TAR container to preserve Unix file permissions and directory structures, followed by compression using the 7z format's LZMA or LZMA2 algorithm. This two-step process addresses the limitation of the 7z format, which does not inherently store Unix owner/group permissions, while leveraging 7-Zip's high compression ratios and solid compression capabilities. The resulting file requires decompression of the 7z layer followed by unpacking of the TAR stream.

Opening this format requires a utility capable of handling the 7z compression algorithm. On Windows, 7-Zip is the primary tool for this specific dual-extension format. macOS users can utilize Keka or The Unarchiver, while Linux users typically employ the p7zip package via command line to first decompress the 7z layer, then extract the underlying TAR.

RAR (Roshal Archive) is a proprietary archive file format developed by Eugene Roshal that supports data compression, error recovery, and file spanning. It utilizes a variation of the LZSS algorithm with a sliding window size of up to 4 MB (in RAR4) or 1 GB (in RAR5), combined with Huffman coding. Key technical features include support for AES-256 encryption, BLAKE2sp hash algorithms for file integrity, and specialized recovery records that allow for the reconstruction of damaged data. The format structure supports solid archiving, where multiple files are treated as a single continuous data stream to improve compression ratios.

Due to the proprietary nature of the RAR licensing, creating RAR files requires licensed software (WinRAR), though extraction is supported by various free tools. Windows users typically use WinRAR or 7-Zip to extract contents. macOS users can utilize The Unarchiver or Keka. On Linux, the non-free unrar package or the open-source 7z (p7zip-full) package provides extraction capabilities via the command line.