VOB tags and VOB access

Nearly every operation that accesses VOB data refers to the VOB by its tag.

A VOB tag holds the following information:

The name of the host on which the VOB's server processes run. The VOB's server processes run on the host where the VOB storage directory is located unless that directory is on a certified NAS device.
The VOB's replica UUID, copied from the VOB object.
A network pathname to the VOB storage directory, expressed in a form that is valid for all hosts that access the VOB. This pathname (called a global path) is used by client programs that need network access to the VOB storage directory.
Default mount options that are applied when the VOB is mounted for use with a dynamic view. For more information, see the mount reference page.
The Public attribute if the VOB was created as a public VOB. For more information about this attribute, see Public and private VOBs.
An optional description, which is displayed by various commands and GUIs.

A VOB must be mounted before it can be accessed by a dynamic view. All operations that mount a VOB refer to it by its tag. A VOB without a tag cannot be mounted.

A VOB does not need to be mounted before it can be accessed by a snapshot or Web view. However, the view's load rules reference VOB tags, and no elements can be loaded into a snapshot or Web view from a VOB that does not have a tag.

In all views, VOB tags are displayed as file-system directories. In a dynamic view, the tags are mounted as though they were network file systems. In snapshot and Web views, VOB tags name the top-level directories that are loaded into the view. Naming rules for VOB tags depend on the platforms that will access the VOBs.

Tags for VOBs accessed by Rational® ClearCase® clients on Windows have only a single leaf, which must begin with a backslash character (for example, \sources).
Tags for VOBs accessed by Rational ClearCase clients running Linux® or the UNIX® system typically have two parts, a mount point and a leaf name (for example, in the VOB tag /vobs/sources, /vobs is the name of the mount point and /sources is the leaf name). Each client host must create the mount point locally before it can mount any VOB.
Note: It is possible in this case to use VOB tags that have only a single leaf; however, limitations on the number of file systems that can be mounted on the root directories of computers running Linux or the UNIX system make such VOB tags impractical for most communities that use dynamic views. When single-leaf VOB tags are being used in a mixed environment of hosts running different supported operating systems, tags that differ only in their initial character—backslash or slash— are equivalent.