HUD — Heads-Up Display

Planned

The HUD is a visual filesystem interface mounted at /Bus/hud/. It provides a structured way for applications and system services to expose status information, controls, and notifications through the display system.

Concept

Instead of each application implementing its own status bar, notification system, or system tray, the HUD provides a unified endpoint:

/Bus/hud/
├── system/
│   ├── cpu          # CPU utilization
│   ├── memory       # Memory usage
│   ├── network      # Network status
│   └── battery      # Battery level (if applicable)
├── notifications/
│   └── <id>         # Active notifications
└── surfaces/
    └── <surface-id> # Active surface metadata

Applications write to HUD endpoints. The Surface Manager reads them and composites them into the display.

Integration

The HUD is tightly integrated with:

• Surface Manager — renders HUD data as overlays
• ProvChain — system health events are logged
• Kinetic Economy — budget warnings appear in the HUD

Why a Filesystem Interface?

Following the Plan 9 philosophy: if it has state, it's a file. The HUD filesystem approach means:

• Any programming language can write HUD data (just write to a file)
• Remote monitoring works through standard file protocols
• Access control uses the same capability system as everything else
• No custom IPC protocols, no D-Bus, no notification daemons