EXCHANGE MOUNT — VMS 5.5
Makes a foreign volume and the files or data it contains available for
processing by EXCHANGE. The EXCHANGE MOUNT command enters the device
into internal tables maintained by EXCHANGE. Note that the device
must previously have been mounted on VMS with the DCL MOUNT command.
Format
EXCHANGE> MOUNT device-name
EXCHANGE> MOUNT /VIRTUAL device-name file-name
Prompts
For MOUNT /FOREIGN:
Device: device-name
For MOUNT /VIRTUAL:
Virtual device: device-name
Filename: file-name
Additional information available:
ParametersDescriptionQualifiersExamples
Parameters
device-name
Specifies the physical device name or logical name of the device
on which the volume is to be mounted. For MOUNT /VIRTUAL, the
device-name parameter supplies a name by which the virtual-device
will be known.
file-name
For MOUNT /VIRTUAL only, the file-name parameter gives the name
of the file containing the image of the foreign volume.
Description
The EXCHANGE MOUNT command enters the description of the foreign
volume in internal tables maintained by EXCHANGE. It is separate
and distinct from the DCL MOUNT command, which enters the device
in tables maintained by the VMS operating system. A volume must
also be mounted on VMS to be accessible to EXCHANGE.
If another EXCHANGE command is given on an unmounted foreign
volume, EXCHANGE will attempt to execute an implied
MOUNT /FOREIGN /WRITE /NODATACHECK on the device. In particular,
this feature is necessary so that EXCHANGE can operate in the
single command DCL mode.
A virtual volume must be explicitly mounted with the
MOUNT /VIRTUAL command.
If a MOUNT /FOREIGN (either implied or explicit) command is given
for a foreign device which has not been mounted on the VMS
system, EXCHANGE will issue the equivalent of the DCL command
$ MOUNT /FOREIGN and attempt to make the volume known to the
operating system. Any volume so mounted by the EXCHANGE MOUNT
command will remain mounted after EXCHANGE exits.
When EXCHANGE issues this $ MOUNT /FOREIGN command, the system
checks:
o That the device has not been allocated to another user
o That a volume is physically loaded on the device specified
o For tapes, the volume accessibility field of the VOL1 label
For more information on managing volumes using MOUNT command
qualifiers, see the VAX/VMS System Management and Operations
Guide. Additional information on mounting is also available in
the VAX/VMS Command Language User's Guide, the VAX/VMS System
Services Reference Manual ($MOUNT system service) and the VAX/VMS
Magnetic Tape User's Guide.
Qualifiers
Additional information available:
/DATA_CHECK/FOREIGN/MESSAGE/VIRTUAL/VOLUME_FORMAT
/WRITE
/DATA_CHECK
/DATA_CHECK=(READ,WRITE)
/NODATA_CHECK
The /DATA_CHECK qualifier determines whether EXCHANGE performs a
second operation after every I/O operation to verify that the
data was correctly transferred.
If /DATA_CHECK=WRITE is specified, after every write operation
EXCHANGE will reread the data just written and compare it against
the original data. If /DATA_CHECK=READ is specified, EXCHANGE
will read each block of data twice and verify that both reads
received identical data.
The /DATA_CHECK qualifier without any options is equivalent to
/DATA_CHECK=WRITE.
It is usually more efficient to use the /DATA_CHECK option on the
VMS MOUNT command than to use the option on the EXCHANGE MOUNT
command. If a device is mounted with the
$ MOUNT /FOREIGN /DATA_CHECK command, VMS is able to use special
features in the device hardware and device driver to perform the
redundant I/O operations. The EXCHANGE data checks are done in
the EXCHANGE software, which results in more overhead.
The RX01 and RX02 floppy diskette drives do not contain the
necessary features for the operating system to perform data
checking. If the $ MOUNT /DATA_CHECK command is given on a
floppy, the system is not able to perform data checking, even
though no warning message is given. EXCHANGE is able to
recognize, however, that a floppy was mounted with data checking.
When it sees this, EXCHANGE will perform the software data
checking inside of EXCHANGE even though no explicit MOUNT
/DATA_CHECK command was given to EXCHANGE.
/FOREIGN
Indicates that the volume is not in the standard format used by
the VAX/VMS operating system; that is, a tape volume is not in
the standard ANSI format, or a disk volume is not in Files-11
format.
The EXCHANGE MOUNT command will only mount foreign volumes. The
/FOREIGN qualifier is the default. Use the DCL command MOUNT to
mount native volumes.
The default protection applied to foreign volumes is RWLP (Read,
Write, Logical I/O, Physical I/O) for the system and owner. If
you mount a volume currently in Files-11 format with the /FOREIGN
qualifier, you must have the user privilege to override volume
protection (VOLPRO), or your UIC must match the UIC on the
volume.
/MESSAGE
/MESSAGE
/NOMESSAGE
The /MESSAGE qualifier controls whether or not EXCHANGE
prints a message which says that the volume was mounted.
The default is determined by the /MESSAGE qualifier on the
EXCHANGE verb when EXCHANGE was activated.
/VIRTUAL
The /VIRTUAL qualifier is used to mount a Files-11 file as a
virtual-device. When /VIRTUAL is used, the MOUNT command takes
two parameters. The first parameter is a device-name which will
be assigned as the name of the virtual-device. The second
parameter is the name of the Files-11 file which is the image of
a foreign volume.
See section 8 for more information on virtual-devices.
/VOLUME_FORMAT
/VOLUME_FORMAT=option
The /VOLUME_FORMAT qualifier defines the physical format of the
volume to be processed. The default format qualifier is
dependent on the device type. The default is /VOLUME_FORMAT=RT11
for block-addressable devices mounted foreign, and
/VOLUME_FORMAT=DOS11 for magnetic tape devices mounted foreign.
Option Function
RT11 Identifies an RT-11 formatted block-
addressable volume
DOS11 Identifies a DOS-11 formatted magnetic tape
volume
See section 6.0 for a complete description of the /VOLUME_FORMAT
qualifier and the defaults.
/WRITE
/WRITE
/NOWRITE
Controls whether the volume can be written.
By default, a volume is considered read/write when it is mounted.
You can specify /NOWRITE to provide read-only access to protect
files. It is equivalent to write-locking the device.
If /WRITE is specified (either explicitly or by default) and the
volume itself is write-locked, EXCHANGE will print a message
explaining that the volume is write-locked.
Examples
1. EXCHANGE> MOUNT MT:
%EXCHANGE-I-MOUNTED, MATH06 mounted on _MTA0:
The MOUNT command requests that the magnetic tape that is
loaded on the device MTA0 be mounted foreign. The tape label
is displayed, since the tape has been previously initialized
as an ANSI labelled tape with the label MATH06. This tape
cannot be accessed as a Files-11 tape, presumably it will be
reinitialized as a DOS-11 tape during the current EXCHANGE
session.
2. EXCHANGE> MOUNT DMA1:
%EXCHANGE-I-WRITELOCK, volume is write-locked
%EXCHANGE-S-MOUNTED, volume DMA1: mounted
The command mounts the foreign volume spinning in the RK07
device DMA1:, making it available to subsequent EXCHANGE
commands. EXCHANGE has recognized that the volume itself is
write-locked, and has printed a message.