Technical data

NFS Client
21.4 Mounting Files and Directories
This mount request increments the mount count by 1. You must specify the
/SHARE qualifier with the same host name and path as used in the initial mount
to ensure that the mount is seen as a shared mount instead of as a new mount
request.
With a shared mount, the mount requests increment the mount count by 1 under
the following circumstances:
• With an initial /SYSTEM or /GROUP mount.
• With a DCL command MOUNT/SHARE or a TCP/IP management command
MOUNT/SHARE that completes without an error. (This contrasts with
overmount, where the previous mounting point is dismounted. This condition
can increment or decrement the mount count or leave it unchanged.)
In this way, if the main process of the job logs out, the job mount is deallocated,
and the volume mount count decrements by 1 (if zero, the device is dismounted).
OpenVMS handles dismounting differently based on whether you use the TCP/IP
management command DISMOUNT or the DCL command DISMOUNT. These
differences are as follows:
• With the TCP/IP command DISMOUNT, the NFS ACP dismounts one or (in
the case of /ALL) more mount points. If the mount point being dismounted is
the only or last one for the device, the device is dismounted for all users who
mounted it, and the mount count is decremented to zero. If more that one
mount point exists, the mount point is dismounted along with a specifically
shared mount.
• With the DCL command DISMOUNT, the OpenVMS operating system
checkes for job mounts first. If a job mount for the specified device exists, the
/JOB mount is dismounted, any logical name associated with the /JOB mount
is deallocated, and the mount count is decremented by one. If no JOB mount
exists, OpenVMS checks for /SYSTEM and /GROUP mounts. If one exists,
and the user has the required privilege, the /SYSTEM or /GROUP mount is
dismounted, any associated logical name is deallocated, and the mount count
is decremented by 1. No mount points are dismounted until the mount count
reaches zero.
If the user does not have the required SYSNAM or GRPNAM privilege, the
following error message is returned:
SYSTEM-F-NO-PRIVILEGE, operation requires privilege
If no /SYSTEM or /GROUP mount exists, the following error message is
returned:
%DISM-W-CANNOTDMT, NFSn: cannot be dismounted
%SYSTEM -F -DEVNOTMOUNT, device is not mounted
Consider the mount counts in the following sample MOUNT/DISMOUNT
sequence:
1. TCPIP> MOUNT DNFS1:/HOST=BART /PATH="/DKA0/ENG"/
Mount count: 1 system mount, not incremented
2.
TCPIP> MOUNT DNFS1:[A] /HOST=BART /PATH="/DKA0/ENG" /SHARE
Mount count: 2 (incremented)
3.
$ MOUNT/SHARE DNFS1:
Mount count: 3 (incremented)
NFS Client 21–9