Double hour (unit), a traditional Chinese unit of time also known as a Watch
operating system | Super Nintendo Entertainment System | Nintendo Entertainment System | Android (operating system) | Global Positioning System | Human Rights Watch | Solar System | X Window System | Third Watch | Korean Broadcasting System | System of a Down | Domain Name System | Seoul Broadcasting System | North Carolina Community College System | Mutual Broadcasting System | Bulletin board system | Black Watch | system | Turner Broadcasting System | Program and System Information Protocol | Geographic information system | Ubuntu (operating system) | Tokyo Broadcasting System | Federal Reserve System | Youth system | Embedded system | solar system | Seigneurial system of New France | Interstate Highway System | Fedora (operating system) |
Depending upon the watch system, two, or even three people may end up sharing the same bunk.