The only software I'm aware of that was written in Modula-3 was "cvsup", used by e.g. FreeBSD Ports and NetBSD pkgsrc to efficiently stream updates to the source tree. The cvsup project itself maintained a subset of the compiler, as the upstream was no longer active.
Now I'm curious and searched around. Apparently three decades ago, an operating system "SPIN" written in Modula-3 was active:
softwarepreservation.computerh…With SPIN, applications can specialize the kernel by dynamically linking new code into the running system. Kernel extensions can add new kernel services, replace default policies, or simply migrate application functionality into the kernel address space. Sensitive kernel interfaces are secured via a restricted linker and the type-safe properties of the Modula-3 programming language.
24 years ago OS News posted about it, and comments declared it a dead research project. The papers about it from the first link are all dated 1996--7.
osnews.com/story/2456/the-spin…
clacke: exhausted pixie dream boy 🇸🇪ðŸ‡ðŸ‡°ðŸ’™ðŸ’›
npub1nj…zq92f
2026-04-27 16:26:02 UTC
in reply to nevent1q…ny0u
Author Public Key
npub1njzrf5yyyfwent50am07cl0anquqrtcce9qsvqv7lc7kvuu3h77qezq92fSeen on
wss://relay.ditto.pubPublished at
2026-04-27 16:26:02 UTCEvent JSON
{
"id": "a797cc7b9c94d0359b6f101c41ba08135d8d603b5e32a3c26f77028952c6fc6f",
"pubkey": "9c8434d084225d99ae8feedfec7dfd983801af18c94106019efe3d667391bfbc",
"created_at": 1777307162,
"kind": 1,
"tags": [
[
"p",
"89d48172eef32d20af9e11580d667d4f5ec195107a408bf9abbe0213d0b8aa1e",
"wss://relay.ditto.pub"
],
[
"e",
"f8db2dad0836546e9a852819a427934252751eeaec4235e83cac4b8d657e1aa0",
"wss://relay.ditto.pub",
"reply"
],
[
"proxy",
"https://libranet.de/objects/0b6b25a8-9969-ef8e-1a3e-c1e550229685",
"activitypub"
],
[
"client",
"Mostr",
"31990:6be38f8c63df7dbf84db7ec4a6e6fbbd8d19dca3b980efad18585c46f04b26f9:mostr",
"wss://relay.ditto.pub"
]
],
"content": "The only software I'm aware of that was written in Modula-3 was \"cvsup\", used by e.g. FreeBSD Ports and NetBSD pkgsrc to efficiently stream updates to the source tree. The cvsup project itself maintained a subset of the compiler, as the upstream was no longer active.\n\nNow I'm curious and searched around. Apparently three decades ago, an operating system \"SPIN\" written in Modula-3 was active:\n\nsoftwarepreservation.computerh…With SPIN, applications can specialize the kernel by dynamically linking new code into the running system. Kernel extensions can add new kernel services, replace default policies, or simply migrate application functionality into the kernel address space. Sensitive kernel interfaces are secured via a restricted linker and the type-safe properties of the Modula-3 programming language.\n\n24 years ago OS News posted about it, and comments declared it a dead research project. The papers about it from the first link are all dated 1996--7.\n\nosnews.com/story/2456/the-spin…",
"sig": "505b12acc0961176dbb1ebce03cf06c0ce382e24ca9c16307d6ca6d690a69a34c5ba780c9a818e30bb99961ccae386ad808e0d8e1bec8aa3f41fa55e06461b83"
}