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Display ​

The Nexus display stack provides sovereign graphics composition without X11, Wayland protocol complexity, or traditional window manager baggage. It follows the same isolation principle as the rest of the system — display composition runs in userland, not the kernel.

Components ​

  • Surface Manager — Sovereign compositor with zero-copy rendering
  • HUD — Visual filesystem interface

Architecture ​

┌──────────────────────────────────┐
│  Applications (NPK)             │  Submit surfaces via SSP
├──────────────────────────────────┤
│  Surface Manager                │  Composites surfaces, 120Hz
│  (Userland Fiber)               │  Zero-copy, per-surface pledge
├──────────────────────────────────┤
│  HUD (/Bus/hud/)                │  Visual filesystem endpoints
├──────────────────────────────────┤
│  ION Ring (Display Channel)     │  Frame delivery
├──────────────────────────────────┤
│  GPU Driver (NPL)               │  Framebuffer access
└──────────────────────────────────┘

Design Philosophy ​

The display stack follows the Plan 9 Rio model: everything is a file-like endpoint. Windows are surfaces. Surfaces are resources in /Bus/hud/. Applications submit frames through the Surface Submission Protocol (SSP) over ION Rings.

The Surface Manager decides what goes on screen. Applications have no direct access to the framebuffer. A compromised application cannot:

  • Read other applications' display content
  • Overlay fake UI elements
  • Capture screenshots
  • Access the GPU directly

This is display isolation without the overhead of running each application in a separate virtual machine (the Qubes OS approach).