# Peios System Protocols Userspace (PSPU) > The foundational userspace protocols — public, stable contracts between the components a Peios system is built from, which third parties may implement. The whole book as one markdown file: [/peios/advanced-peios/pspu/print.md](/peios/advanced-peios/pspu/print.md) Contents: - 1 [Introduction](/peios/advanced-peios/pspu/introduction/scope.md) - 1.1 [Scope](/peios/advanced-peios/pspu/introduction/scope.md) - 1.2 [Conventions](/peios/advanced-peios/pspu/introduction/conventions.md) - 2 [Principal Source Interface](/peios/advanced-peios/pspu/principal-source-interface/scope-and-roles.md) - 2.1 [Scope and Roles](/peios/advanced-peios/pspu/principal-source-interface/scope-and-roles.md) - 2.2 [Terminology](/peios/advanced-peios/pspu/principal-source-interface/terminology.md) - 2.3 [Sources Dial In](/peios/advanced-peios/pspu/principal-source-interface/sources-dial-in.md) - 2.4 [Assert, Never Mint](/peios/advanced-peios/pspu/principal-source-interface/assert-never-mint.md) - 2.5 [A Superset of PGSS Logon](/peios/advanced-peios/pspu/principal-source-interface/a-superset-of-pgss-logon.md) - 2.6 [The Channel](/peios/advanced-peios/pspu/principal-source-interface/the-channel.md) - 2.7 [Message Framing](/peios/advanced-peios/pspu/principal-source-interface/message-framing.md) - 2.8 [Registration](/peios/advanced-peios/pspu/principal-source-interface/registration.md) - 2.9 [Establishing What a Source Is](/peios/advanced-peios/pspu/principal-source-interface/establishing-what-a-source-is.md) - 2.10 [The Domain Claim](/peios/advanced-peios/pspu/principal-source-interface/the-domain-claim.md) - 2.11 [Authenticate](/peios/advanced-peios/pspu/principal-source-interface/authenticate.md) - 2.12 [The Relayed Interrogation](/peios/advanced-peios/pspu/principal-source-interface/the-relayed-interrogation.md) - 2.13 [Assertion and Refusal](/peios/advanced-peios/pspu/principal-source-interface/assertion-and-refusal.md) - 2.14 [Abandon](/peios/advanced-peios/pspu/principal-source-interface/abandon.md) - 2.15 [Query](/peios/advanced-peios/pspu/principal-source-interface/query.md) - 2.16 [Enumeration](/peios/advanced-peios/pspu/principal-source-interface/enumeration.md) - 2.17 [Change Notification](/peios/advanced-peios/pspu/principal-source-interface/change-notification.md) - 2.18 [Identity Confinement](/peios/advanced-peios/pspu/principal-source-interface/identity-confinement.md) - 2.19 [Membership Scope](/peios/advanced-peios/pspu/principal-source-interface/membership-scope.md) - 2.20 [Numeric Scope](/peios/advanced-peios/pspu/principal-source-interface/numeric-scope.md) - 2.21 [Conformance](/peios/advanced-peios/pspu/principal-source-interface/conformance.md) - Appendix 2.A [Message Reference](/peios/advanced-peios/pspu/principal-source-interface/message-reference.md) - Appendix 2.B [Enumerations](/peios/advanced-peios/pspu/principal-source-interface/enumerations.md) - Appendix 2.C [What Is Shared with PGSS Logon](/peios/advanced-peios/pspu/principal-source-interface/what-is-shared-with-pgss-logon.md) - Appendix 2.D [Prior Art](/peios/advanced-peios/pspu/principal-source-interface/prior-art.md) - 3 [Observability Interfaces](/peios/advanced-peios/pspu/observability-interfaces/scope-and-roles.md) - 3.1 [Scope and Roles](/peios/advanced-peios/pspu/observability-interfaces/scope-and-roles.md) - 3.2 [Terminology](/peios/advanced-peios/pspu/observability-interfaces/terminology.md) - 3.3 [Three Channels](/peios/advanced-peios/pspu/observability-interfaces/three-channels.md) - 3.4 [Loss and Backpressure](/peios/advanced-peios/pspu/observability-interfaces/loss-and-backpressure.md) - 3.5 [Encoding and Time](/peios/advanced-peios/pspu/observability-interfaces/encoding-and-time.md) - 3.6 [The Log Channel](/peios/advanced-peios/pspu/observability-interfaces/the-log-channel.md) - 3.7 [Log Records](/peios/advanced-peios/pspu/observability-interfaces/log-records.md) - 3.8 [Validating a Log Record](/peios/advanced-peios/pspu/observability-interfaces/validating-a-log-record.md) - 3.9 [The Metric Channel](/peios/advanced-peios/pspu/observability-interfaces/the-metric-channel.md) - 3.10 [The Metric Data Model](/peios/advanced-peios/pspu/observability-interfaces/the-metric-data-model.md) - 3.11 [Metric Records](/peios/advanced-peios/pspu/observability-interfaces/metric-records.md) - 3.12 [Validating a Metric Record](/peios/advanced-peios/pspu/observability-interfaces/validating-a-metric-record.md) - 3.13 [Series Identity](/peios/advanced-peios/pspu/observability-interfaces/series-identity.md) - 3.14 [The Query Channel](/peios/advanced-peios/pspu/observability-interfaces/the-query-channel.md) - 3.15 [Query Framing](/peios/advanced-peios/pspu/observability-interfaces/query-framing.md) - 3.16 [Responses](/peios/advanced-peios/pspu/observability-interfaces/responses.md) - 3.17 [Value Encoding](/peios/advanced-peios/pspu/observability-interfaces/value-encoding.md) - 3.18 [The Query Language](/peios/advanced-peios/pspu/observability-interfaces/the-query-language.md) - 3.19 [Lexical Rules and Literals](/peios/advanced-peios/pspu/observability-interfaces/lexical-rules-and-literals.md) - 3.20 [Comparison and Logic](/peios/advanced-peios/pspu/observability-interfaces/comparison-and-logic.md) - 3.21 [Ordering, Grouping and Distinct](/peios/advanced-peios/pspu/observability-interfaces/ordering-grouping-and-distinct.md) - 3.22 [Fields and Results](/peios/advanced-peios/pspu/observability-interfaces/fields-and-results.md) - 3.23 [Event Queries](/peios/advanced-peios/pspu/observability-interfaces/event-queries.md) - 3.24 [Log Queries](/peios/advanced-peios/pspu/observability-interfaces/log-queries.md) - 3.25 [Metric Queries](/peios/advanced-peios/pspu/observability-interfaces/metric-queries.md) - 3.26 [Cross-Type Filtering](/peios/advanced-peios/pspu/observability-interfaces/cross-type-filtering.md) - 3.27 [Streaming](/peios/advanced-peios/pspu/observability-interfaces/streaming.md) - 3.28 [What a Client Cannot See](/peios/advanced-peios/pspu/observability-interfaces/what-a-client-cannot-see.md) - 3.29 [Extension](/peios/advanced-peios/pspu/observability-interfaces/extension.md) - 3.30 [Conformance](/peios/advanced-peios/pspu/observability-interfaces/conformance.md) - Appendix 3.A [Limits](/peios/advanced-peios/pspu/observability-interfaces/limits.md) - Appendix 3.B [Query Language Reference](/peios/advanced-peios/pspu/observability-interfaces/query-language-reference.md) - Appendix 3.C [Prior Art](/peios/advanced-peios/pspu/observability-interfaces/prior-art.md) - 4 [Service Control and Notification](/peios/advanced-peios/pspu/service-control-and-notification/scope-and-roles.md) - 4.1 [Scope and Roles](/peios/advanced-peios/pspu/service-control-and-notification/scope-and-roles.md) - 4.2 [Terminology](/peios/advanced-peios/pspu/service-control-and-notification/terminology.md) - 4.3 [The Two Channels](/peios/advanced-peios/pspu/service-control-and-notification/the-two-channels.md) - 4.4 [The Control Channel](/peios/advanced-peios/pspu/service-control-and-notification/the-control-channel.md) - 4.5 [Framing and Encoding](/peios/advanced-peios/pspu/service-control-and-notification/framing-and-encoding.md) - 4.6 [Peer Identity](/peios/advanced-peios/pspu/service-control-and-notification/peer-identity.md) - 4.7 [Authorising a Command](/peios/advanced-peios/pspu/service-control-and-notification/authorising-a-command.md) - 4.8 [Requests](/peios/advanced-peios/pspu/service-control-and-notification/requests.md) - 4.9 [Responses](/peios/advanced-peios/pspu/service-control-and-notification/responses.md) - 4.10 [Errors](/peios/advanced-peios/pspu/service-control-and-notification/errors.md) - 4.11 [Lifecycle Commands](/peios/advanced-peios/pspu/service-control-and-notification/lifecycle-commands.md) - 4.12 [Command Outcomes by State](/peios/advanced-peios/pspu/service-control-and-notification/command-outcomes.md) - 4.13 [Wait Semantics](/peios/advanced-peios/pspu/service-control-and-notification/wait-semantics.md) - 4.14 [Query Commands](/peios/advanced-peios/pspu/service-control-and-notification/query-commands.md) - 4.15 [System Commands](/peios/advanced-peios/pspu/service-control-and-notification/system-commands.md) - 4.16 [The Notification Channel](/peios/advanced-peios/pspu/service-control-and-notification/the-notification-channel.md) - 4.17 [Datagram Framing](/peios/advanced-peios/pspu/service-control-and-notification/datagram-framing.md) - 4.18 [Sender Authentication](/peios/advanced-peios/pspu/service-control-and-notification/sender-authentication.md) - 4.19 [Notification Fields](/peios/advanced-peios/pspu/service-control-and-notification/notification-fields.md) - 4.20 [The Descriptor Store](/peios/advanced-peios/pspu/service-control-and-notification/the-descriptor-store.md) - 4.21 [Extension](/peios/advanced-peios/pspu/service-control-and-notification/extension.md) - 4.22 [Conformance](/peios/advanced-peios/pspu/service-control-and-notification/conformance.md) - Appendix 4.A [Limits and Defaults](/peios/advanced-peios/pspu/service-control-and-notification/limits.md) - Appendix 4.B [Wire Vocabulary](/peios/advanced-peios/pspu/service-control-and-notification/vocabulary.md) - 5 [Package Format and Repository Protocol](/peios/advanced-peios/pspu/package-format-and-repository-protocol/scope-and-roles.md) - 5.1 [Scope and Roles](/peios/advanced-peios/pspu/package-format-and-repository-protocol/scope-and-roles.md) - 5.2 [Terminology](/peios/advanced-peios/pspu/package-format-and-repository-protocol/terminology.md) - 5.3 [Package Names](/peios/advanced-peios/pspu/package-format-and-repository-protocol/package-names.md) - 5.4 [Virtual Names](/peios/advanced-peios/pspu/package-format-and-repository-protocol/virtual-names.md) - 5.5 [Versions](/peios/advanced-peios/pspu/package-format-and-repository-protocol/versions.md) - 5.6 [Comparing Versions](/peios/advanced-peios/pspu/package-format-and-repository-protocol/comparing-versions.md) - 5.7 [Version Constraints](/peios/advanced-peios/pspu/package-format-and-repository-protocol/version-constraints.md) - 5.8 [Architectures](/peios/advanced-peios/pspu/package-format-and-repository-protocol/architectures.md) - 5.9 [Document Conventions](/peios/advanced-peios/pspu/package-format-and-repository-protocol/document-conventions.md) - 5.10 [The Container](/peios/advanced-peios/pspu/package-format-and-repository-protocol/the-container.md) - 5.11 [Determinism](/peios/advanced-peios/pspu/package-format-and-repository-protocol/determinism.md) - 5.12 [Internal Layout](/peios/advanced-peios/pspu/package-format-and-repository-protocol/internal-layout.md) - 5.13 [Payload Paths](/peios/advanced-peios/pspu/package-format-and-repository-protocol/payload-paths.md) - 5.14 [Install Destinations](/peios/advanced-peios/pspu/package-format-and-repository-protocol/install-destinations.md) - 5.15 [The Architecture Triplet](/peios/advanced-peios/pspu/package-format-and-repository-protocol/the-architecture-triplet.md) - 5.16 [Payload Entries](/peios/advanced-peios/pspu/package-format-and-repository-protocol/payload-entries.md) - 5.17 [Symlinks](/peios/advanced-peios/pspu/package-format-and-repository-protocol/symlinks.md) - 5.18 [The Manifest](/peios/advanced-peios/pspu/package-format-and-repository-protocol/the-manifest.md) - 5.19 [Installation Roots](/peios/advanced-peios/pspu/package-format-and-repository-protocol/installation-roots.md) - 5.20 [Security Descriptor Overrides](/peios/advanced-peios/pspu/package-format-and-repository-protocol/security-descriptor-overrides.md) - 5.21 [Relationships](/peios/advanced-peios/pspu/package-format-and-repository-protocol/relationships.md) - 5.22 [Derived Capabilities](/peios/advanced-peios/pspu/package-format-and-repository-protocol/derived-capabilities.md) - 5.23 [Claim Declarations](/peios/advanced-peios/pspu/package-format-and-repository-protocol/claim-declarations.md) - 5.24 [Side-Effect Declarations](/peios/advanced-peios/pspu/package-format-and-repository-protocol/side-effect-declarations.md) - 5.25 [The Files Manifest](/peios/advanced-peios/pspu/package-format-and-repository-protocol/the-files-manifest.md) - 5.26 [Verifying a Package](/peios/advanced-peios/pspu/package-format-and-repository-protocol/verifying-a-package.md) - 5.27 [Decompression Bounds](/peios/advanced-peios/pspu/package-format-and-repository-protocol/decompression-bounds.md) - 5.28 [Package Signatures](/peios/advanced-peios/pspu/package-format-and-repository-protocol/package-signatures.md) - 5.29 [Keys and Fingerprints](/peios/advanced-peios/pspu/package-format-and-repository-protocol/keys-and-fingerprints.md) - 5.30 [Verifying a Signature](/peios/advanced-peios/pspu/package-format-and-repository-protocol/verifying-a-signature.md) - 5.31 [The Repository Descriptor](/peios/advanced-peios/pspu/package-format-and-repository-protocol/the-repository-descriptor.md) - 5.32 [Signing Key Status and Rotation](/peios/advanced-peios/pspu/package-format-and-repository-protocol/signing-key-status-and-rotation.md) - 5.33 [The Active Index](/peios/advanced-peios/pspu/package-format-and-repository-protocol/the-active-index.md) - 5.34 [Freshness and Rollback Protection](/peios/advanced-peios/pspu/package-format-and-repository-protocol/freshness-and-rollback-protection.md) - 5.35 [The Archive Index](/peios/advanced-peios/pspu/package-format-and-repository-protocol/the-archive-index.md) - 5.36 [URL Conventions](/peios/advanced-peios/pspu/package-format-and-repository-protocol/url-conventions.md) - 5.37 [Establishing Trust in a Repository](/peios/advanced-peios/pspu/package-format-and-repository-protocol/establishing-trust-in-a-repository.md) - 5.38 [Extension](/peios/advanced-peios/pspu/package-format-and-repository-protocol/extension.md) - 5.39 [Conformance](/peios/advanced-peios/pspu/package-format-and-repository-protocol/conformance.md) - Appendix 5.A [Limits and Defaults](/peios/advanced-peios/pspu/package-format-and-repository-protocol/limits-and-defaults.md) - Appendix 5.B [Enumerated Values](/peios/advanced-peios/pspu/package-format-and-repository-protocol/enumerated-values.md)