Lifo
Try Demo

The kernel

The Kernel owns a box's durable state — the filesystem, process table, virtual network, ports, and boot-time setup.

The Kernel is the bottom of the stack — the object that owns everything persistent about a box. Sandbox.create() builds one for you, but you can also construct a Kernel directly for lower-level use.

import { Kernel } from "@lifo-sh/core";

const kernel = new Kernel(/* optional persistence backend */);

What the kernel owns

  • vfs — the virtual filesystem, an in-memory tree with pluggable providers.
  • processRegistry — the process table (PIDs, status, abort controllers).
  • networkStack — the virtual network: interfaces, sockets, DNS, routes, tunnels.
  • portRegistry — a Map<number, handler> of listening ports; how an in-VM server is reached (and how previews find it).
  • portBridge — routes virtual requests to the handler registered for a port.
  • persistence — a PersistenceManager that saves the VFS to a backend (IndexedDB in the browser, in-memory otherwise).
  • serviceManager — a systemd-lite that runs unit files (systemctl).

Boot-time setup

Constructing a kernel lays down a believable base system:

  • Mounts synthetic providers: /proc (process info) and /dev.
  • Writes /etc/motd, /etc/hostname (lifo), /etc/profile, and ~/.liforc (Lifo's .bashrc).
  • Seeds /etc/hosts and loads it into the network stack's DNS resolver.
  • Installs a set of sample files.

When persistence is enabled, the kernel watches the VFS and schedules a save on every change, so a box's disk survives a page reload.

Note

The kernel is intentionally thin. It holds state and wires subsystems together; the behavior lives in the shell, the commands, and the Node runtime that run on top of it.

Requests and handlers

The kernel exposes a small request/response contract used by the network and preview layers:

  • VirtualRequest / VirtualResponse — a minimal HTTP-like message pair.
  • VirtualRequestHandler — what a listening port registers so incoming requests reach it.

This is the seam the service worker bridge and tunnels plug into to expose an in-VM port to the outside world.