Urbit Developers
  • Hoon

    • Overview
    • Cheat Sheet
    • Irregular forms
    • Hoon Errors
    • Hoon Style Guide
    • Basic Types
    • Advanced Types
    • Auras
    • Arvo
    • Standard Library

      • 1a: Basic Arithmetic
      • 1b: Tree Addressing
      • 1c: Molds and Mold-Builders
      • 2a: Unit Logic
      • 2b: List Logic
      • 2c: Bit Arithmetic
      • 2d: Bit Logic
      • 2e: Insecure Hashing
      • 2f: Noun Ordering
      • 2g: Unsigned Powers
      • 2h: Set Logic
      • 2i: Map Logic
      • 2j: Jar and Jug Logic
      • 2k: Queue Logic
      • 2l: Container from Container
      • 2m: Container from Noun
      • 2n: Functional Hacks
      • 2o: Normalizing Containers
      • 2p: Serialization
      • 2q: Molds and Mold-Builders
      • 3a: Modular and Signed Ints
      • 3b: Floating Point
      • 3c: Urbit Time
      • 3d: SHA Hash Family
      • 3e: AES encryption (Removed)
      • 3f: Scrambling
      • 3g: Molds and Mold-Builders
      • 4a: Exotic Bases
      • 4b: Text Processing
      • 4c: Tank Printer
      • 4d: Parsing (Tracing)
      • 4e: Parsing (Combinators)
      • 4f: Parsing (Rule-Builders)
      • 4g: Parsing (Outside Caller)
      • 4h: Parsing (ASCII Glyphs)
      • 4i: Parsing (Useful Idioms)
      • 4j: Parsing (Bases and Base Digits)
      • 4k: Atom Printing
      • 4l: Atom Parsing
      • 4m: Formatting Functions
      • 4n: Virtualization
      • 4o: Molds
      • 5a: Compiler Utilities
      • 5b: Macro Expansion
      • 5c: Compiler Backend & Prettyprinter
      • 5d: Parser
      • 5e: Molds and mold builders
      • 5f: Profiling support
      • Runes

        • Constants (Atoms and Strings)
        • + lus · Arms
        • | bar · Cores
        • $ buc · Structures
        • % cen · Calls
        • : col · Cells
        • . dot · Nock
        • / fas · Imports
        • ^ ket · Casts
        • ; mic · Make
        • ~ sig · Hints
        • = tis · Subject
        • ? wut · Conditionals
        • ! zap · Wild
        • --, == Terminators
        • Limbs and wings

          • Limbs
          • Wings
          • Zuse

            • 2d(1-5): To JSON, Wains
            • 2d(6): From JSON
            • 2d(7): From JSON (unit)
            • 2e(2-3): Print & Parse JSON
            • 2m: Ordered Maps
          • Arvo

            • Overview
            • Ames

              • Overview
              • Cryptography
              • API Reference
              • Scry Reference
              • Data Types
              • Behn

                • Overview
                • API Reference
                • Scry Reference
                • Examples
                • Clay

                  • Overview
                  • Architecture
                  • Using Clay
                  • Data Types
                  • Scry Reference
                  • API Reference
                  • Examples
                  • Marks

                    • Overview
                    • Writing Marks
                    • Using Marks
                    • Examples
                  • Dill

                    • Overview
                    • API Reference
                    • Scry Reference
                    • Data Types
                    • Eyre

                      • Overview
                      • External API Reference
                      • Internal API Reference
                      • Scry Reference
                      • Data Types
                      • Guide
                      • Gall

                        • Overview
                        • API Reference
                        • Data Types
                        • Threads Reference
                        • Iris

                          • Overview
                          • API Reference
                          • Data Types
                          • Example
                          • Jael

                            • Overview
                            • API Reference
                            • Scry Reference
                            • Data Types
                            • Examples
                            • Khan

                              • Overview
                              • API Reference
                              • Data Types
                              • Example
                              • Threads

                                • Overview
                                • HTTP API
                                • Reference
                                • Gall

                                  • Start Thread
                                  • Take Result
                                  • Take Facts
                                  • Stop Thread
                                  • Poke Thread
                                  • Examples

                                    • Fetch JSON
                                    • Child Thread
                                    • Main-loop
                                    • Poke Agent
                                    • Scry
                                    • Take Fact
                                  • Concepts

                                    • Scries
                                    • Subscriptions
                                    • Tutorials

                                      • Move Trace
                                      • Reference

                                        • Cryptography
                                        • Filesystem Hierarchy
                                      • Nock

                                        • Nock Definition
                                        • Explanation
                                        • Example
                                        • Implementations
                                        • Vere

                                          • C Runtime System
                                          • Land of Nouns
                                          • API overview by prefix
                                          • C in Urbit
                                          • Writing Jets
                                          • Cryptography
                                          • Azimuth

                                            • Overview
                                            • Urbit HD Wallet
                                            • Azimuth Data Flow
                                            • Azimuth.eth
                                            • Ecliptic.eth
                                            • Advanced Azimuth Tools
                                            • Life and Rift
                                            • Layer 2

                                              • Layer 2 Overview
                                              • Layer 2 Actions
                                              • Transaction Format
                                              • Rollers
                                              • Roller HTTP RPC-API
                                              • Custom Roller Tutorial
                                            • Glossary

                                              • Agent
                                              • Ames
                                              • API
                                              • Aqua
                                              • Arm
                                              • Arvo
                                              • Atom
                                              • Aura
                                              • Aural ASCII
                                              • Azimuth
                                              • Battery
                                              • Behn
                                              • Bowl
                                              • Bridge
                                              • Bunt
                                              • Card
                                              • Case
                                              • Cask
                                              • Cell
                                              • Censures
                                              • Claims
                                              • Clay
                                              • Cold atom
                                              • Comet
                                              • Commit
                                              • Cons
                                              • Context
                                              • Cord
                                              • Core
                                              • Delegated Sending
                                              • Desk
                                              • Dill
                                              • Document Proposal
                                              • Dojo
                                              • Door
                                              • Double-boot
                                              • Dry Gate
                                              • Duct
                                              • Ecliptic
                                              • Entropy
                                              • Event Log
                                              • Eyre
                                              • Face
                                              • Fact
                                              • Foo Bar Baz
                                              • Galaxy
                                              • Gall
                                              • Garden
                                              • Gate
                                              • Generator
                                              • Gift
                                              • Glob
                                              • HD Wallet
                                              • Helm
                                              • Hood
                                              • Hoon
                                              • Invite Tree
                                              • Iris
                                              • Jael
                                              • Jet
                                              • Kelvin versioning
                                              • Kelvin versioning
                                              • Keyfile
                                              • Keywords
                                              • Khan
                                              • Kiln
                                              • Landscape
                                              • Leg
                                              • List
                                              • Loobean
                                              • Lull
                                              • Mark
                                              • Metals
                                              • Mold
                                              • Monad
                                              • Moon
                                              • Move
                                              • Nock
                                              • Noun
                                              • ~
                                              • OTA Updates
                                              • Path Prefix
                                              • Path
                                              • @p
                                              • Payload
                                              • Peek
                                              • pH
                                              • Pier
                                              • Pill
                                              • Planet
                                              • Poke
                                              • Proxies
                                              • Replay
                                              • Factory Reset
                                              • Roller
                                              • Naive rollups
                                              • Rune
                                              • Runtime
                                              • Sail
                                              • Sample
                                              • Scry
                                              • Senate
                                              • Ship
                                              • Slam
                                              • Spider
                                              • Sponsor
                                              • Star
                                              • String
                                              • Subject Oriented Programming
                                              • Subject
                                              • Subscription
                                              • Tape
                                              • Thread
                                              • Trap
                                              • Udon
                                              • Upgrade Proposal
                                              • Userspace
                                              • Vane
                                              • Vase
                                              • Vere
                                              • Voting
                                              • Warm atom
                                              • Wet Gate
                                              • Wing
                                              • Wire
                                              • Wrapper
                                              • ~zod
                                              • Zuse
                                              • Additional

                                                • Cryptography
                                                • Mips (Maps of Maps)
                                                • Software Distribution

                                                  • Overview
                                                  • Docket File
                                                  • Glob
                                                Urbit Developers
                                                • Hoon

                                                  • Overview
                                                  • Cheat Sheet
                                                  • Irregular forms
                                                  • Hoon Errors
                                                  • Hoon Style Guide
                                                  • Basic Types
                                                  • Advanced Types
                                                  • Auras
                                                  • Arvo
                                                  • Standard Library

                                                    • 1a: Basic Arithmetic
                                                    • 1b: Tree Addressing
                                                    • 1c: Molds and Mold-Builders
                                                    • 2a: Unit Logic
                                                    • 2b: List Logic
                                                    • 2c: Bit Arithmetic
                                                    • 2d: Bit Logic
                                                    • 2e: Insecure Hashing
                                                    • 2f: Noun Ordering
                                                    • 2g: Unsigned Powers
                                                    • 2h: Set Logic
                                                    • 2i: Map Logic
                                                    • 2j: Jar and Jug Logic
                                                    • 2k: Queue Logic
                                                    • 2l: Container from Container
                                                    • 2m: Container from Noun
                                                    • 2n: Functional Hacks
                                                    • 2o: Normalizing Containers
                                                    • 2p: Serialization
                                                    • 2q: Molds and Mold-Builders
                                                    • 3a: Modular and Signed Ints
                                                    • 3b: Floating Point
                                                    • 3c: Urbit Time
                                                    • 3d: SHA Hash Family
                                                    • 3e: AES encryption (Removed)
                                                    • 3f: Scrambling
                                                    • 3g: Molds and Mold-Builders
                                                    • 4a: Exotic Bases
                                                    • 4b: Text Processing
                                                    • 4c: Tank Printer
                                                    • 4d: Parsing (Tracing)
                                                    • 4e: Parsing (Combinators)
                                                    • 4f: Parsing (Rule-Builders)
                                                    • 4g: Parsing (Outside Caller)
                                                    • 4h: Parsing (ASCII Glyphs)
                                                    • 4i: Parsing (Useful Idioms)
                                                    • 4j: Parsing (Bases and Base Digits)
                                                    • 4k: Atom Printing
                                                    • 4l: Atom Parsing
                                                    • 4m: Formatting Functions
                                                    • 4n: Virtualization
                                                    • 4o: Molds
                                                    • 5a: Compiler Utilities
                                                    • 5b: Macro Expansion
                                                    • 5c: Compiler Backend & Prettyprinter
                                                    • 5d: Parser
                                                    • 5e: Molds and mold builders
                                                    • 5f: Profiling support
                                                    • Runes

                                                      • Constants (Atoms and Strings)
                                                      • + lus · Arms
                                                      • | bar · Cores
                                                      • $ buc · Structures
                                                      • % cen · Calls
                                                      • : col · Cells
                                                      • . dot · Nock
                                                      • / fas · Imports
                                                      • ^ ket · Casts
                                                      • ; mic · Make
                                                      • ~ sig · Hints
                                                      • = tis · Subject
                                                      • ? wut · Conditionals
                                                      • ! zap · Wild
                                                      • --, == Terminators
                                                      • Limbs and wings

                                                        • Limbs
                                                        • Wings
                                                        • Zuse

                                                          • 2d(1-5): To JSON, Wains
                                                          • 2d(6): From JSON
                                                          • 2d(7): From JSON (unit)
                                                          • 2e(2-3): Print & Parse JSON
                                                          • 2m: Ordered Maps
                                                        • Arvo

                                                          • Overview
                                                          • Ames

                                                            • Overview
                                                            • Cryptography
                                                            • API Reference
                                                            • Scry Reference
                                                            • Data Types
                                                            • Behn

                                                              • Overview
                                                              • API Reference
                                                              • Scry Reference
                                                              • Examples
                                                              • Clay

                                                                • Overview
                                                                • Architecture
                                                                • Using Clay
                                                                • Data Types
                                                                • Scry Reference
                                                                • API Reference
                                                                • Examples
                                                                • Marks

                                                                  • Overview
                                                                  • Writing Marks
                                                                  • Using Marks
                                                                  • Examples
                                                                • Dill

                                                                  • Overview
                                                                  • API Reference
                                                                  • Scry Reference
                                                                  • Data Types
                                                                  • Eyre

                                                                    • Overview
                                                                    • External API Reference
                                                                    • Internal API Reference
                                                                    • Scry Reference
                                                                    • Data Types
                                                                    • Guide
                                                                    • Gall

                                                                      • Overview
                                                                      • API Reference
                                                                      • Data Types
                                                                      • Threads Reference
                                                                      • Iris

                                                                        • Overview
                                                                        • API Reference
                                                                        • Data Types
                                                                        • Example
                                                                        • Jael

                                                                          • Overview
                                                                          • API Reference
                                                                          • Scry Reference
                                                                          • Data Types
                                                                          • Examples
                                                                          • Khan

                                                                            • Overview
                                                                            • API Reference
                                                                            • Data Types
                                                                            • Example
                                                                            • Threads

                                                                              • Overview
                                                                              • HTTP API
                                                                              • Reference
                                                                              • Gall

                                                                                • Start Thread
                                                                                • Take Result
                                                                                • Take Facts
                                                                                • Stop Thread
                                                                                • Poke Thread
                                                                                • Examples

                                                                                  • Fetch JSON
                                                                                  • Child Thread
                                                                                  • Main-loop
                                                                                  • Poke Agent
                                                                                  • Scry
                                                                                  • Take Fact
                                                                                • Concepts

                                                                                  • Scries
                                                                                  • Subscriptions
                                                                                  • Tutorials

                                                                                    • Move Trace
                                                                                    • Reference

                                                                                      • Cryptography
                                                                                      • Filesystem Hierarchy
                                                                                    • Nock

                                                                                      • Nock Definition
                                                                                      • Explanation
                                                                                      • Example
                                                                                      • Implementations
                                                                                      • Vere

                                                                                        • C Runtime System
                                                                                        • Land of Nouns
                                                                                        • API overview by prefix
                                                                                        • C in Urbit
                                                                                        • Writing Jets
                                                                                        • Cryptography
                                                                                        • Azimuth

                                                                                          • Overview
                                                                                          • Urbit HD Wallet
                                                                                          • Azimuth Data Flow
                                                                                          • Azimuth.eth
                                                                                          • Ecliptic.eth
                                                                                          • Advanced Azimuth Tools
                                                                                          • Life and Rift
                                                                                          • Layer 2

                                                                                            • Layer 2 Overview
                                                                                            • Layer 2 Actions
                                                                                            • Transaction Format
                                                                                            • Rollers
                                                                                            • Roller HTTP RPC-API
                                                                                            • Custom Roller Tutorial
                                                                                          • Glossary

                                                                                            • Agent
                                                                                            • Ames
                                                                                            • API
                                                                                            • Aqua
                                                                                            • Arm
                                                                                            • Arvo
                                                                                            • Atom
                                                                                            • Aura
                                                                                            • Aural ASCII
                                                                                            • Azimuth
                                                                                            • Battery
                                                                                            • Behn
                                                                                            • Bowl
                                                                                            • Bridge
                                                                                            • Bunt
                                                                                            • Card
                                                                                            • Case
                                                                                            • Cask
                                                                                            • Cell
                                                                                            • Censures
                                                                                            • Claims
                                                                                            • Clay
                                                                                            • Cold atom
                                                                                            • Comet
                                                                                            • Commit
                                                                                            • Cons
                                                                                            • Context
                                                                                            • Cord
                                                                                            • Core
                                                                                            • Delegated Sending
                                                                                            • Desk
                                                                                            • Dill
                                                                                            • Document Proposal
                                                                                            • Dojo
                                                                                            • Door
                                                                                            • Double-boot
                                                                                            • Dry Gate
                                                                                            • Duct
                                                                                            • Ecliptic
                                                                                            • Entropy
                                                                                            • Event Log
                                                                                            • Eyre
                                                                                            • Face
                                                                                            • Fact
                                                                                            • Foo Bar Baz
                                                                                            • Galaxy
                                                                                            • Gall
                                                                                            • Garden
                                                                                            • Gate
                                                                                            • Generator
                                                                                            • Gift
                                                                                            • Glob
                                                                                            • HD Wallet
                                                                                            • Helm
                                                                                            • Hood
                                                                                            • Hoon
                                                                                            • Invite Tree
                                                                                            • Iris
                                                                                            • Jael
                                                                                            • Jet
                                                                                            • Kelvin versioning
                                                                                            • Kelvin versioning
                                                                                            • Keyfile
                                                                                            • Keywords
                                                                                            • Khan
                                                                                            • Kiln
                                                                                            • Landscape
                                                                                            • Leg
                                                                                            • List
                                                                                            • Loobean
                                                                                            • Lull
                                                                                            • Mark
                                                                                            • Metals
                                                                                            • Mold
                                                                                            • Monad
                                                                                            • Moon
                                                                                            • Move
                                                                                            • Nock
                                                                                            • Noun
                                                                                            • ~
                                                                                            • OTA Updates
                                                                                            • Path Prefix
                                                                                            • Path
                                                                                            • @p
                                                                                            • Payload
                                                                                            • Peek
                                                                                            • pH
                                                                                            • Pier
                                                                                            • Pill
                                                                                            • Planet
                                                                                            • Poke
                                                                                            • Proxies
                                                                                            • Replay
                                                                                            • Factory Reset
                                                                                            • Roller
                                                                                            • Naive rollups
                                                                                            • Rune
                                                                                            • Runtime
                                                                                            • Sail
                                                                                            • Sample
                                                                                            • Scry
                                                                                            • Senate
                                                                                            • Ship
                                                                                            • Slam
                                                                                            • Spider
                                                                                            • Sponsor
                                                                                            • Star
                                                                                            • String
                                                                                            • Subject Oriented Programming
                                                                                            • Subject
                                                                                            • Subscription
                                                                                            • Tape
                                                                                            • Thread
                                                                                            • Trap
                                                                                            • Udon
                                                                                            • Upgrade Proposal
                                                                                            • Userspace
                                                                                            • Vane
                                                                                            • Vase
                                                                                            • Vere
                                                                                            • Voting
                                                                                            • Warm atom
                                                                                            • Wet Gate
                                                                                            • Wing
                                                                                            • Wire
                                                                                            • Wrapper
                                                                                            • ~zod
                                                                                            • Zuse
                                                                                            • Additional

                                                                                              • Cryptography
                                                                                              • Mips (Maps of Maps)
                                                                                              • Software Distribution

                                                                                                • Overview
                                                                                                • Docket File
                                                                                                • Glob
                                                                                              Reference

                                                                                              Arvo

                                                                                              Resources about the Urbit OS.

                                                                                              Overview

                                                                                              Arvo is Urbit's functional operating system, written in Hoon. It's composed of modules called vanes, each of which has its own folder:

                                                                                              Ames

                                                                                              Ames is the name of our network and the vane that communicates over it. It's an encrypted P2P network composed of instances of the Arvo operating system.

                                                                                              Behn

                                                                                              Behn is our timer. It allows vanes and applications to set and timer events, which are managed in a simple priority queue.

                                                                                              Clay

                                                                                              Clay is our filesystem and revision-control system.

                                                                                              Dill

                                                                                              Dill is our terminal driver. Unix sends keyboard events to dill from the terminal, and dill produces terminal output.

                                                                                              Eyre

                                                                                              Eyre is our HTTP server. Unix sends HTTP messages to %eyre, and %eyre produces HTTP messages in response.

                                                                                              Gall

                                                                                              Gall is the vane for controlling userspace apps.

                                                                                              Iris

                                                                                              Iris is our HTTP client.

                                                                                              Jael

                                                                                              Jael manages keys and Azimuth state.

                                                                                              Khan

                                                                                              Khan is our thread dispatcher.

                                                                                              Concepts

                                                                                              Explanations of design decisions that are pervasive throughout Arvo.

                                                                                              Tutorials

                                                                                              Walkthroughs that teach you more about how Arvo works.

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                                                                                              Last modified March 17, 2023