Urbit
An operating function
...It has an identity layer (Azimuth), virtual machine (Vere), and operating system (Arvo). A running Urbit "ship" is designed to operate with other ships peer-to-peer. Urbit is a general-purpose, peer-to-peer computer and network. Urbit is for everyone, but sometimes it is easy to get lost in this universe. It solves the hard problems of implementing a peer-to-peer network (including identity, NAT traversal, and exactly-once delivery) in the kernel so app developers can focus on business logic. The entire OS is a single pure function that provides application developers with strong guarantees: automated persistence and memory management, repeatable builds, and support for hot code reloading. ...