MPE/iX Shell and Utilities Reference Manual, Vol 2

• A group directory does not contain explicit dot (.) and dot-dot (..) directories; however, dot and
dot-dot directory behavior is supported. You can open the dot and dot-dot directories just like any
other hierarchical directory. You can use file information routines to return information about
these directories.
• You cannot modify the user ID (UID) and group ID (GID) associated with a group directory through
MPE/iX Shell and Utilities.
• The ability to create files under a group directory (including hierarchical directories and files at all
levels under a group directory) is also determined by the
MPE/iX save files (SF) capability, which
must be assigned to the
MPE/iX user attempting to create an object at any level under a group direc-
tory.
• A group directory must have MPE/iX save access assigned to it before you can create files or
directories under it. For more information about MPE/iX save access, refer to the manual Control-
ling System Activity (32650-90155).
Hierarchical Directory Features
• You cannot rename hierarchical directories through MPE/iX Shell and Utilities. You can only
remove hierarchical directories when they are empty (containing only the dot (.) and dot-dot (..)
directory entries).
• Users can define and modify access permissions for hierarchical directories through MPE/iX Shell
and Utilities.
• A hierarchical directory inherits its group ID (GID) from its parent directory and its user ID (UID)
from the user who created it. You can use chown to modify the
UID and GID of a hierarchical
directory.
• Hierarchical directories (and all objects under them) that are not under
MPE/iX account and group
directories are restricted to the MPE/iX system volume set.
• Names of hierarchical directories and files located directly under the root directory, an account, or
a group cannot exceed 16 characters in length.
• Names of hierarchical directories that are not directly under either the root directory or group
directories cannot exceed 255 characters in length.
• MPE/iX accounting limits for disk space apply to both hierarchical directories and files located at
all levels under group directories.
• Hierarchical directories contain explicit dot (.) and dot-dot (..) directory entries.
Dot (.) and Dot-Dot (..) Directory Features
When mkdir first creates a hierarchical directory, it places two special directory entries in the hierar-
chical directory: dot (.) and dot-dot (..).
A-12 MPE/iX Implementation Considerations