In order to allow easy installation and configuration of third-party software into all systems, GNO/ME provides a feature called named prefixes. These prefixes are defined in the /etc/namespace file. Basically, since all UNIX systems have /bin, /usr, /etc, and other similar standard partitions, but Apple IIgs systems generally do not have these partitions, named prefixes provide a way to simulate the UNIX directories without forcing GNO/ME users to rename their partitions (an arduous and problem-filled task).
Named prefixes are handled by the GNO kernel in the same GS/OS calls described in Chapter 3 Pathnames and Prefixes. The format of the /etc/namespace file can be found in the namespace(5) manual page.
Note that if you have a physical partition that matches the name of a logical partition defined in the /etc/namespace file, then the physical parition will not be visible while running GNO.