Chromium OS

Chromium OS is a Linux distribution designed by Google to work primarily with web applications. It is the open source development version of Chrome OS.
Overview
Architecture
In preliminary design documents, Google describes a three-tier architecture: firmware, web browser and window manager, and system-level software and userland services.

• The firmware contributes to fast boot time by not probing for hardware, such as floppy disk drives, that are no longer common on computers, especially netbooks. The firmware also contributes to security by verifying each step in the boot process and incorporating system recovery.
• System-level software includes the Linux kernel that has been patched to improve boot performance. Userland software has been trimmed to essentials, with management by Upstart, which can launch services in parallel, re-spawn crashed jobs, and defer services in the interest of faster booting.
• The window manager handles user interaction with multiple client windows much like other X window managers.