6cy – Experimental streaming archive format with per-block codecs
Hi HN, I’ve been experimenting with archive format design and built 6cy as a research project. The goal is not to replace zip/7z, but to explore: • block-level codec polymorphism (different compression per block) • streaming-first layout (no global seek required) • better crash recovery characteristics • plugin-based architecture so proprietary codecs can exist without changing the format Right now this is an experimental v0.x format. The specification may still change and compatibility is not guaranteed yet. I’m mainly looking for feedback on the format design rather than performance…
6cy – Experimental streaming archive format with per-block codecs launched on February 17, 2026 with 35 votes, #639 of 16,627 launches that month and more than 95% of that year's launches.
In plain words
6cy is an experimental archive format designed to explore alternative approaches to data compression and storage. It features block-level codec flexibility, allowing different compression methods per block, and prioritizes streaming without requiring global seek operations. The format includes improved crash recovery and a plugin architecture for custom codecs. Currently at version 0.x, the specification remains subject to change. It targets researchers and developers interested in archive format design rather than serving as a replacement for established formats like zip or 7z.
written from the facts on this page · September 2026
From the sources
High-performance, streaming-first container format with per-block codec polymorphism and robust data recoverability. Reference implementation in Rust. - byte271/6cy
# Pack files into an archive 6cy pack -o archive.6cy -i file1.txt file2.txt # List archive contents 6cy list archive.6cy # Extract files 6cy unpack archive.6cy -C ./output_dir # View archive info 6cy info archive.6cy # Create encrypted archive 6cy pack -o secure.6cy -i sensitive.dat --password " mypassword " # Use FEC for error recovery (10 data shards, 4 parity shards) 6cy pack -o resilient.6cy -i data/ --fec 10/4 # Use content-defined chunking for deduplication 6cy pack -o dedup.6cy -i data/ --cdc --merkle # Recover from damaged archive 6cy recover damaged.6cy -o recovered.6cy # Merge archives 6cy merge archive1.6cy archive2.6cy -o merged.6cy CLI Commands Command Description pack Create…from github.com
In the maker’s words, at launch
Hi HN, I’ve been experimenting with archive format design and built 6cy as a research project. The goal is not to replace zip/7z, but to explore: • block-level codec polymorphism (different compression per block) • streaming-first layout (no global seek required) • better crash recovery characteristics •…
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