Open System Services Management and Operations Guide (G06.30+, H06.08+, J06.03+)

OSS environment; these catalogs contain uniquely numbered data structures for each file and
directory, called inode numbers and link numbers.
Figure 1 shows that the OSS name servers resolve Guardian filenames and OSS pathnames to
each other, then provide the information used by the system on behalf of the application program
to communicate with the disk process, which provides access to the file on disk. Furthermore, each
OSS filename points to an underlying Guardian file ID, such as Z0000DV3 in the figure.
For further information about the OSS file system, see “Understanding the OSS File System”
(page 80)
The /G Directory
The /G directory provides OSS names for Guardian files on your local NonStop node. Each
Guardian filename has a corresponding OSS name of the form /G/volume/subvolume/fileID,
where volume, subvolume, and fileID are case-insensitive; for example,
$SYSTEM.SYS00.CONFLIST becomes /G/system/sys00/conflist.
The /G directory itself is reserved for HP use. You cannot put anything in this directory. You also
cannot add a directory at the /G/volume level of the directory hierarchy.
If you add or delete files below the /G/volume level of this directory, you increase or decrease
the amount of disk space used. However, the increase or decrease affects only the disk volumes
that contain the Guardian files, which can be different from the volumes that contain OSS files.
Therefore, if users delete files from the /G directory, they might not free space for OSS files and
can lose files that they intended to keep.
The /G directory is described in more detail in “Understanding the OSS File System” (page 80).
The /E Directory
The /E directory provides OSS names for OSS and Guardian files on remote NonStop nodes.
Each remote filename has a corresponding OSS name of the form:
• /E/nodename/pathname for OSS files
• /E/nodename/G/volume/subvolume/fileID for Guardian files
where nodename, volume, subvolume, and fileID are case-insensitive.
For example:
• The OSS file /tmp/datafile on \NODE2 becomes /E/node2/tmp/datafile
• The Guardian file $SYSTEM.SYS00.CONFLIST on \NODE2 becomes
/E/node2/G/system/sys00/conflist.
The /E directory itself is reserved for HP use. You cannot put anything in this directory.
If you add or delete Guardian files below the /G/volume level of this directory, you increase or
decrease the amount of disk space used on the corresponding NonStop node. However, the
increase or decrease affects only the disk volumes that contain the Guardian files—which can be
different from the volumes that contain OSS files.
If you add or delete OSS files below the /nodename level of this directory, you increase or
decrease the amount of disk space used on the corresponding NonStop node. However, the
increase or decrease affects only the disk volumes that contain the OSS files, which can be different
from the volumes that contain Guardian files.
Figure 2 shows how the /E directory on your local node allows remote file access through an
Expand network.
OSS File System Concepts 31