UC2: UltraCompressor II¶
A cross-platform revival of UltraCompressor II, the DOS-era archiver by Nico de Vries (1992-1996). UC2 was notable for its advanced deduplication (“master blocks”), file versioning, and competitive compression ratios on the hardware of its day.
UC2 v3 brings it back as a modern, portable C99 tool with both decompression and compression, targeting Linux, macOS, Windows, and DOS.
Open an archive in your browser to inspect stored versions,
verify checksums and download selected file versions as a ZIP. Save the reader
for offline use while connected. Archive data stays on your device.
For collections, uc2-preserve inventories and migrates UC2 archives to
verified ZIP/tar exports. See the preservation guide.
uc2 snapshot in the Python package creates incremental directory versions
with shared chunks, verified restores, explicit retention and replica repair. See the snapshot guide.
The optional --chunked writer shares payload chunks across named files and
stored versions; see the chunk-sharing guide for compatibility.
The native CLI also supports tar ingestion with separate entries and data-only SAS/UC2SEA reads. See the tar guide and volume guide.