{"slug": "ironclad", "name": "Ironclad", "category": "os", "category_name": "Operating systems and desktop", "description": "", "recommenders": 5, "commenters": 8, "warners": 1, "score": 4.039, "rising": 1.02, "first": "2025-11-08", "latest": "2026-10-02", "why": "What I like most about ironclad is that it is fully posix-compliant", "why_is_quote": true, "has_verdict": false, "sentiment": {"recommend": 5, "neutral": 2, "compare": 0, "warn": 1}, "spark": [3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2], "listed": true, "loved": [], "caveat": "", "short_quote": "What I like most about ironclad is that it is fully posix-compliant", "kind": "", "icon": true, "domain": "ironclad-os.org", "github_repo": null, "official_url": "https://ironclad-os.org", "pricing": "", "aliases": ["Ironclad", "Ironclad OS"], "verdict": null, "praise": [{"label": "", "summary": "", "quotes": [{"id": 733887536, "item_id": 45867971, "url": "https://news.ycombinator.com/item?id=45867971", "by": "ajdude", "date": "2025-11-09", "version": null, "stance": "recommend", "quote": "What I like most about ironclad is that it is fully posix-compliant", "excerpt": "What I like most about ironclad is that it is fully posix-compliant, meaning that you can run a lot of UNIX programs on it already, like what \"Gloire\" does: https://github.com/Ironclad-Project/Gloire", "context": "", "use_case": "", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}, {"id": 733832416, "item_id": 45864526, "url": "https://news.ycombinator.com/item?id=45864526", "by": "Rochus", "date": "2025-11-09", "version": null, "stance": "recommend", "quote": "Ironclad has a POSIX API, so yes, in principle it should be possible.", "excerpt": "Ironclad has a POSIX API, so yes, in principle it should be possible. There is an OS on top of Ironclad (https://github.com/Ironclad-Project/Gloire) which uses GNU tools.", "context": "", "use_case": "OS kernel", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}, {"id": 733804768, "item_id": 45862798, "url": "https://news.ycombinator.com/item?id=45862798", "by": "rurban", "date": "2025-11-08", "version": null, "stance": "recommend", "quote": "The MAC's are good", "excerpt": "The MAC's are good: https://ironclad-os.org/manual/Mandatory-access-control-_0028MAC_0029.html", "context": "", "use_case": "", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}]}], "caveats": [{"label": "", "summary": "", "quotes": [{"id": 733806801, "item_id": 45862925, "url": "https://news.ycombinator.com/item?id=45862925", "by": "AlotOfReading", "date": "2025-11-08", "version": null, "stance": "warn", "quote": "I don't see any interesting specifications in the repo, just basic stuff like this MD5 spec [0] that doesn't verify whether the MD5 implementation is correct.", "excerpt": "That really depends on what formal verification means in context. I don't see any interesting specifications in the repo, just basic stuff like this MD5 spec [0] that doesn't verify whether the MD5 implementation is correct. This is one of the areas where formal verification is listed as completed/gold level. It's common for the interesting OS proofs to take more code than the kernel itself. Take a look at the seL4 p", "context": "", "use_case": "", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}]}], "who": [], "tags": [], "use_cases": ["os kernel"], "compared": [{"slug": "sel4", "name": "seL4", "co": 2, "switched_from": 0, "switched_to": 0}], "makers": [], "threads": [{"url": "https://news.ycombinator.com/item?id=45860843", "title": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel", "mentions": 6}, {"url": "https://news.ycombinator.com/item?id=49928121", "title": "Several vulnerabilities have been discovered in the Linux kernel", "mentions": 2}], "sentiment_by_month": {"2025-11": {"neutral": 2, "recommend": 3, "warn": 1}, "2025-12": {}, "2026-01": {}, "2026-02": {}, "2026-03": {}, "2026-04": {}, "2026-05": {}, "2026-06": {}, "2026-07": {}, "2026-08": {}, "2026-09": {}, "2026-10": {"recommend": 2}}, "versions": [], "version_unnamed": 0, "family_ref": null, "runs_on": null, "lines": [], "quotes": [{"id": 798968017, "item_id": 49935501, "url": "https://news.ycombinator.com/item?id=49935501", "by": "abathologist", "date": "2026-10-02", "version": null, "stance": "recommend", "quote": "", "excerpt": "https://sel4.systems/ is relevant in this space!", "context": "", "use_case": "", "switched_from": "", "story": "Several vulnerabilities have been discovered in the Linux kernel"}, {"id": 798880784, "item_id": 49930049, "url": "https://news.ycombinator.com/item?id=49930049", "by": "csrse", "date": "2026-10-02", "version": null, "stance": "recommend", "quote": "", "excerpt": "There is also LionsOS https://lionsos.org/ (SeL4-based).", "context": "", "use_case": "", "switched_from": "", "story": "Several vulnerabilities have been discovered in the Linux kernel"}, {"id": 733887536, "item_id": 45867971, "url": "https://news.ycombinator.com/item?id=45867971", "by": "ajdude", "date": "2025-11-09", "version": null, "stance": "recommend", "quote": "What I like most about ironclad is that it is fully posix-compliant", "excerpt": "What I like most about ironclad is that it is fully posix-compliant, meaning that you can run a lot of UNIX programs on it already, like what \"Gloire\" does: https://github.com/Ironclad-Project/Gloire", "context": "", "use_case": "", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}, {"id": 733851232, "item_id": 45865702, "url": "https://news.ycombinator.com/item?id=45865702", "by": "beanjuiceII", "date": "2025-11-09", "version": null, "stance": "neutral", "quote": "(partially) formally verified says right on the page", "excerpt": "(partially) formally verified says right on the page https://ironclad-os.org/formalverification.html", "context": "", "use_case": "", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}, {"id": 733832416, "item_id": 45864526, "url": "https://news.ycombinator.com/item?id=45864526", "by": "Rochus", "date": "2025-11-09", "version": null, "stance": "recommend", "quote": "Ironclad has a POSIX API, so yes, in principle it should be possible.", "excerpt": "Ironclad has a POSIX API, so yes, in principle it should be possible. There is an OS on top of Ironclad (https://github.com/Ironclad-Project/Gloire) which uses GNU tools.", "context": "", "use_case": "OS kernel", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}, {"id": 733806801, "item_id": 45862925, "url": "https://news.ycombinator.com/item?id=45862925", "by": "AlotOfReading", "date": "2025-11-08", "version": null, "stance": "warn", "quote": "I don't see any interesting specifications in the repo, just basic stuff like this MD5 spec [0] that doesn't verify whether the MD5 implementation is correct.", "excerpt": "That really depends on what formal verification means in context. I don't see any interesting specifications in the repo, just basic stuff like this MD5 spec [0] that doesn't verify whether the MD5 implementation is correct. This is one of the areas where formal verification is listed as completed/gold level. It's common for the interesting OS proofs to take more code than the kernel itself. Take a look at the seL4 p", "context": "", "use_case": "", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}, {"id": 733804768, "item_id": 45862798, "url": "https://news.ycombinator.com/item?id=45862798", "by": "rurban", "date": "2025-11-08", "version": null, "stance": "recommend", "quote": "The MAC's are good", "excerpt": "The MAC's are good: https://ironclad-os.org/manual/Mandatory-access-control-_0028MAC_0029.html", "context": "", "use_case": "", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}, {"id": 733801376, "item_id": 45862586, "url": "https://news.ycombinator.com/item?id=45862586", "by": "anta40", "date": "2025-11-08", "version": null, "stance": "neutral", "quote": "For typical end users, kernel on its own is useless. So this an example of OS which uses Ironclad kernel:", "excerpt": "For typical end users, kernel on its own is useless. So this an example of OS which uses Ironclad kernel: https://codeberg.org/Ironclad/Gloire", "context": "", "use_case": "", "switched_from": "", "story": "Ironclad \u2013 formally verified, real-time capable, Unix-like OS kernel"}]}