A minimal-heap supervisor spawns the compositor and shell as separate, capability-scoped processes. The compositor owns every rendering decision; the shell only decides what to draw.
No frame timer — page-flip events pace rendering. The display hardware itself drives the loop, giving zero jitter at any refresh rate including VRR.
Every major Linux compositor is written in C or C++ with a native rendering path. Sabas OS's whole graphics pipeline runs on the JVM instead.
| Sabas OS | GNOME Mutter / Linux |
KDE Plasma KWin / Linux |
Sway wlroots / Linux |
Windows 11 DWM / DirectX |
macOS Sequoia Quartz / Metal |
|
|---|---|---|---|---|---|---|
| Implementation language | Java 25 (Panama FFM) | C | C++ | C | C / C++ | C / Obj-C / Swift |
| Source available | fully open source | open source | open source | open source | proprietary | proprietary |
| Native glue / C shims | None | - | - | wlroots (C) | Win32 / COM | CoreGraphics (C) |
| GPU / display path | Direct Vulkan + DRM/KMS | OpenGL/Vulkan via Cogl | OpenGL/Vulkan via KWin | OpenGL via wlroots | DirectX 12 / DXGI | Metal / CoreAnimation |
| Zero-copy multi-GPU scanout | 6 selectable paths (A-F) | driver-dependent | driver-dependent | driver-dependent | driver-dependent | Apple Silicon only |
| Render-loop memory model | GC-free, pooled buffers | manual (C) | manual (C++) | manual (C) | manual (C++) | ARC / manual (C) |
| Shell / compositor isolation | 3 supervised JVMs | single process | single process | single process | kernel + csrss.exe | WindowServer (single) |
| Workspace namespace isolation | 7 Linux namespaces | none | none | none | partial (AppContainer) | partial (sandbox) |
| Telemetry / data collection | zero, none at all | minimal, opt-out | minimal, opt-out | none | extensive, opt-out | moderate, opt-out |
| Built-in AI subsystem | local Ollama + MCP | none | none | none | Copilot (cloud) | Apple Intelligence (cloud) |
| App toolkit | native Java render tree | GTK | Qt / QML | client-dependent | Win32 / WinUI 3 | AppKit / SwiftUI |
| Hardware vendor lock-in | none - any Vulkan GPU | none | none | none | x86-64 only | Apple hardware only |