The Remote Magnetic Tape (RMT) client and Remote Compact Disc (RCD) client provide access to tape drives and CD-ROM drives, respectively, on remote TCP/IP systems. This chapter describes how to set up RMT and RCD on your OpenVMS system so that you can use the commands typically associated with tape and CD-ROM drives, such as BACKUP, MOUNT, COPY, and EXCHANGE.
To use a remote tape or CD-ROM, you must first "connect" to the server system with the RMTSETUP command, which creates a pseudo device. You can then use OpenVMS commands such as BACKUP, MOUNT, COPY, and EXCHANGE. These are the same commands issued directly to the physical tape or CD-ROM device on the server. When you conclude the activity, you can discard the pseudo device using the DEALLOCATE command.
Note that not all tape drives or CD-ROM drives can fully support use of the RMT client and RCD client. For example, quarter-inch tape drives on UNIX systems typically support only fixed-length, 512-byte records. You cannot use these tapes with the OpenVMS COPY or BACKUP commands because the latter require variable-length records.
An attempt to perform an unsupported operation to a remote device results in a %SYSTEM-E-UNSUPPORTED error message.
You can lose the TCP/IP connection between the RMT or RCD client and server if:
· An RMT or RCD server receives a command that it does not recognize. Rather than returning an error message, it simply closes the connection.
· A bug in an RMT or RCD server causes it to crash.
· If the RMT or RCD server (or its system) crashes or is shut down.
In these situations, the RMT client or RCD client detects the loss of the TCP/IP connection and returns the following error message for all subsequent commands:
%SYSTEM-F-LINKABORT, network partner aborted logical link
The only alternative at this point is to deallocate the existing device and reconnect to the server (when it becomes available) by running RMTSETUP again.
Configures an RMT or RCD pseudo device, _RMTn: or _RCDn:, respectively, on your local OpenVMS system. In this way you can perform functions on remote magnetic tape or CD-ROM drives connected to an RMT or RCD server. The remote RMT or RCD server must support the rmt protocol.
Connecting to a remote CD-ROM drive requires the /CD qualifier. You can connect to the remote host with a different username by specifying the optional /USERNAME qualifier on the command line.
RMTSETUP host remote-device [logical]
host
Name or internet address of the host on which the remote tape or CD-ROM drive resides. This host must have an RMT server available.
remote-device
Name of the remote tape device (such as MKB500:) or CD-ROM device (such as DKA200:) on the RMT server. If sending the device and any server options to a non-TCPware server, you must enclose this information in double quotes, such as "/dev/rst0" for a UNIX server with "read-only" privileges.
logical
Optional OpenVMS logical assigned to the newly created pseudo device. If omitted, RMTSETUP uses the logical name TCPWARE_TAPE for tapes and TCPWARE_DISK for disks.
Not all RMT servers support the following RMT Client qualifiers as options or qualifiers. For UNIX servers, for example, you must include options as part of remote-device as a quoted string. For example, "/dev/mt0" is a stream device and "/dev/rmt0" is a non-stream device. With a TCPware RMT server, where remote-device is not a quoted string, the client qualifiers that are also server qualifiers are sent to the server.
/ASSIST
/NOASSIST
Action to take when the device cannot mount on the remote system. With /ASSIST (the default), operator messages appear on the remote system indicating corrective action to take (if supported). With /NOASSIST, only a local message appears. Not allowed when used with /CD.
/BLOCKSIZE=size
Default block size of the remote tape device. Not allowed when used with /CD.
/CD
Indicates that the remote device is a CD-ROM device.
/COMMENT="string"
Used with the /ASSIST qualifier to send a message to the remote operator when a mount operation fails. Not allowed when used with /CD.
/DENSITY=density
Density, in bits per inch, at which to write the remote tape. Not allowed when used with /CD.
/LOG
/NOLOG
/LOG displays log information during RMTSETUP execution. /NOLOG, the default, does not.
/MOUNT
/NOMOUNT
/MOUNT, the default, allows the user exclusive access to the device. /NOMOUNT disables exclusive access to the device. /NOMOUNT also prevents a remote tape from rewinding when deallocating the pseudo device on the client. Not allowed when used with /CD.
You cannot combine /NOMOUNT with /ASSIST, /BLOCKSIZE, /COMMENT, or /DENSITY.
Use /NOMOUNT carefully since it allows multiple users access to the same device.
/PASSWORD[=password]
/NOPASSWORD
/PASSWORD sets the password to access the remote system and causes the RMT server to use the rexec rather than the rshell service. The password is converted to lowercase unless you enclose it in quotes. /NOPASSWORD uses the rexec service with a blank password. Without either qualifier, access to the remote tape device is controlled through the TCPWARE:HOST.EQUIV and SYS$LOGIN:.RHOSTS files. Use together with /USERNAME.
Using the password value can pose a security risk. Also, using a null password for which you have to be prompted can cause an error in a command procedure.
/REWIND
/NOREWIND
/REWIND, on by default, rewinds a tape before its initial use. /NOREWIND causes the tape to stay in an arbitrary position after running RMTSETUP. Not allowed when used with /CD.
/STREAM
/NOSTREAM
A tape is normally written as a series of records. /STREAM ignores record boundaries and returns data read from the tape as a stream of bytes (the UNIX model). Not allowed when used with /CD.
Most OpenVMS utilities expect tape drives to operate in non-stream mode, so take care in overriding the /NOSTREAM default.
/TRUNCATE_USERNAME[=length]
Truncates the username sent to the RMT server to the specified length to accommodate requirements of some non-OpenVMS systems. The default length is 8.
/UNLOAD
/NOUNLOAD
/UNLOAD, the default, unloads the remote device when deallocating the local RMT pseudo device. /NOUNLOAD disables this. Note that a DCL MOUNT or DISMOUNT with /UNLOAD or /NOUNLOAD overrides the RMTSETUP /UNLOAD or /NOUNLOAD. Not allowed when used with /CD.
/USERNAME=username
Username for access to the remote system. If omitted, the username of the client process is sent to the server (subject to truncation by /TRUNCATE_USERNAME). username is converted to lowercase unless you enclose it in quotes. Use together with /PASSWORD.
/WRITE
/NOWRITE
Writing to the remote tape is usually enabled with the default /WRITE. /NOWRITE is a precautionary measure to prevent a remote tape from being written. Not allowed when used with /CD.
1. This example uses tape drive MKB500: on remote
OpenVMS system IRIS to back up all the TCPware data files that start with SM. The tape is left loaded in the drive after its use
(/NOUNLOAD). MYTAPE is
the logical name for the _RMT9: device created.
$ RMTSETUP IRIS MKB500: MYTAPE /NOUNLOAD /LOG
Connecting to RMT server on host IRIS through port 514 (rsh)
Opening MKB500:/NOSTREAM/NOUNLOAD
_RMT9: created
$ BACKUP /LOG
TCPWARE:SM*.DAT MYTAPE:TCPWARE.BCK /SAVE_SET
%MOUNT-I-MOUNTED, TEST1 mounted on _RMT9:
%BACKUP-S-COPIED, copied SYS$SPECIFIC:[TCPWARE]SM.DAT;1
%BACKUP-S-COPIED, copied SYS$SPECIFIC:[TCPWARE]SM_BAK.DAT;1
$ DISMOUNT MYTAPE
/NOUNLOAD
$ DEALLOCATE MYTAPE
2. This example requests access to tape drive /dev/rst0 on a remote UNIX system, using a username and password. The initialize command was unrecognized by the tape drive on the UNIX system and rejected. The tar utility examines the contents of the tape, which was written from the UNIX system. (tar is available over the network and is an alternative to the EXCHANGE utility).
$ rmtsetup sigma.nene.com "/dev/rst0" -
_$ /username=system
/password
Password for root on host SIGMA.EXAMPLE.COM: ******
$ initialize
tcpware_tape test
%INIT-F-UNSUPPORTED, unsupported operation or function
$ mount /foreign
/record_size=512 tcpware_tape
$ tar -ftv tcpware_tape
644 4069 Jun 1 16:29:21 2021 /etc/hosts
End of Tar file found.
Do you wish to move past the EOF mark (y/n)? n
$ dismount tcpware_tape
$ deallocate tcpware_tape
3. This example requests access to CD-ROM drive DKA100: on remote host roman, mounts the CD-ROM using MY_CD as the logical name, and requests a directory listing:
$ rmtsetup /cd /log roman dka100: my_cd
Connecting to RCD server on host ROMAN through port 514 (rsh)
Opening DKA100:
_RCD1: created
$ mount my_cd
/override=id
%MOUNT-I-WRITELOCK, volume is write locked
%MOUNT-I-MOUNTED, OPENVMS062 mounted on _ALTARF$RCD1:
$ dir my_cd:[0,0]