TAR.Z (TZ) to TAR.7Z (T7Z) Converter

TAR.Z is a compound archive format combining TAR archiving with Unix compress, one of the earliest general-purpose data compression tools available on Unix systems. The compress utility, originally written by Spencer Thomas, Joe Orost, and others around 1985, implements adaptive LZW (Lempel-Ziv-Welch) compression — a dictionary-based algorithm that builds a translation table during compression and decompression. The TAR layer bundles files with full Unix metadata into a single stream, and compress reduces the stream size typically by 40-60%. TAR.Z was the standard compressed archive format on Unix systems throughout the 1980s and early 1990s, before gzip emerged as a patent-free replacement. The LZW algorithm used by compress was subject to patent claims by Unisys (holders of the LZW patent through Sperry), which motivated the development of gzip as an unencumbered alternative. One advantage is universal legacy compatibility — TAR.Z files can be extracted on any Unix system, including very old installations where newer compression tools may not be available. The format's historical ubiquity means that decades of archived software, documentation, and system backups exist as TAR.Z files. While TAR.GZ and TAR.XZ have replaced TAR.Z for new archives, the uncompress/zcat tools remain standard on all Unix-like systems, ensuring continued accessibility of legacy archives.