844c1ab092
The 2015 LGPL re-release was initiated by Vladislav Sagunov's request
to Nico de Vries; de Vries personally re-released the source. Earlier
CREDITS.md (and the inherited license-audit.md) misattributed this to
Danny Bezemer. Bezemer was a co-developer of UC2 during the original
1992-1996 work, per de Vries's release notes.
Add docs/blog/uc2-revival-writeup.md (1200 words) drafted from the
codex-reviewed revision: tightened scoping language ('byte-bitstream-
compatible' rather than ambiguous 'byte-compatible'), removed
overclaims about borg/restic/Kopia equivalence, dropped speculative
PQ/Filecoin/ZK details, and trimmed the demo to one compatibility
example + one OTS example.
Closes git-bug 98904d0.
3.2 KiB
Credits
Original UltraCompressor II
Nico de Vries created UltraCompressor II (1992--1996), a DOS archiver
with LZ77+Huffman compression, master-block deduplication, and file
versioning. The original source code is preserved in original/UC2_source/.
2015 LGPL Source Release
In December 2015, Vladislav Sagunov asked Nico de Vries whether
the UC2 source could be re-released under a free licence. De Vries
agreed and personally re-published the full UC2 source under the GNU
LGPL-3.0 (with a small Borland C/C++ runtime carve-out for DOS-specific
code). The release notes are preserved verbatim in
original/UC2_source/Read Me First.txt.
Portable Decompressor (unuc2 / libunuc2)
Jan Bobrowski wrote a clean-room portable decompressor (2020--2021) that
forms the foundation of this project's decompression engine. The library
(libunuc2) is licensed under LGPL-3.0; the CLI tool (unuc2) is licensed
under GPL-3.0-or-later.
The following files in this repository derive directly from Bobrowski's
work and retain his licence (see docs/license-audit.md for the full
provenance table):
lib/src/decompress.c(LGPL-3.0-only) -- derived fromlibunuc2.clib/src/list.h(LGPL-3.0-only) -- byte-identical to upstreamlib/include/uc2/libuc2.h(LGPL-3.0-only) -- derived fromlibunuc2.hcli/src/main.c(GPL-3.0-or-later) -- derived fromunuc2.c, with substantial additions for archive creation, OTS, and benchmarkingcli/src/compat/compat_win32.c(LGPL-3.0-only)cli/src/compat/compat_dos.c(LGPL-3.0-only, DOS adaptation by Valetov)
The SuperMaster dictionary (lib/src/super.bin) is bit-identical to the
copy shipped in original/unuc2-0.6/ and to the data extracted from
de Vries's 1992 binaries.
- Website: http://torinak.com/~jb/unuc2/
- Original source preserved in
original/unuc2-0.6/
Additional Contributors
- Danny Bezemer -- co-authored UC2 with de Vries during the original 1992-1996 development.
- Jan-Pieter Cornet -- early testing, archive samples, and format documentation contributions to the unuc2 project.
UC2 v3.0.0 Revival
Eremey Valetov -- project revival, including:
- CMake build system and cross-platform porting (Linux, macOS, MSVC, DJGPP)
- LZ77+Huffman compression engine (compatible with original UC2 Pro)
- rANS entropy coder (method 10, levels 6--9)
- Content-defined chunking (CDC) with Gear rolling hash
- Merkle DAG content addressing
- Cross-archive block store for shared deduplication
- SimHash near-duplicate detection
- Delta compression for binary patching
- Content-aware preprocessing (BCJ, BWT, delta filter)
- LZ4 ultra-fast compression
- BLAKE3 cryptographic hashing
- SHA-256 (FIPS 180-4) implementation
- OpenTimestamps integration (proof parser, walker, archive trailer)
- Dictionary metadata for cross-archive sharing
- Backward compatibility with original UC2 Pro (verified via DOSBox-X)
- Automated test infrastructure (19 unit tests, DOSBox-X cross-tool testing)
All files under "UC2 v3.0.0 Revival" are licensed GPL-3.0-or-later by
Eremey Valetov (2026). See docs/license-audit.md for the per-file
provenance table and the LGPL-3.0 / GPL-3.0 chain rationale.
- GitHub: https://github.com/evvaletov/uc2