In Sun Solaris 10, zones are a virtualization technology that provides isolation and a secure environment for applications. The global zone is the initial zone of the Solaris 10 operating system. This zone has full privileges and is the zone that is running when the system is booted. A non-global zone is a virtual machine that resides on top of the operating system proper, with its own host name, IP address, set of filesystems, and so on. A non-global zone is commonly called a zone.
A non-global zone can use either a full root (a separate copy of all the filesystems on the global zone) or it can have a sparse root (read-only access to some filesystems that are shared with the global zone (for example, /usr) and some zone-specific filesystems such as /etc and /var). A zone provides namespace and process space isolation, as well as separation from the physical devices and network interface names. This isolation provides a level of security by preventing processes in a non-global zone from monitoring or affecting either the global zone or another non-global zone.
This information is just a summary of the features provided by non-global zones. For details about how global and non-global zones are implemented and used in Sun Solaris 10, see the documentation on the Sun product Web site (http://www.sun.com).
Before you can install or run Rational ClearCase in a non-global zone, certain configuration steps are required.