Experiments
Implementation experiments in Airlock OS.
sys-clipboard: a Hermit unikernel
The default sys-clipboard VM runs the shared clipboard service on
Hermit, a Rust-based
unikernel. A unikernel links an application with the
operating-system runtime it needs into one executable. Here, that executable
runs directly on Xen, without Linux or a NixOS installation inside the VM.
The clipboard service keeps its contents in memory. It needs no persistent filesystem, root disk, or package manager. Running only the service and its runtime allows the VM to use much less RAM than a conventional general-purpose OS. The clipboard service and Hermit runtime are written in Rust.
The experiment is in using a dedicated runtime for a small system service while keeping a separate VM boundary. Nix still builds the executable, and the machine configuration connects the service to the desktop's participating VMs.
The service is integrated with the desktop: adapters in the participating VMs send and retrieve clipboard contents. Every admitted participant can read and replace the shared clipboard.
The clipboard implementation contains the service and its Hermit entry point. The Hermit–Xen integration provides the Xen support used by the VM.