HP OpenVMS Systems Documentation

HP OpenVMS DCL Dictionary

Connects your terminal (through the current host processor) to another processor, called the remote processor. The command requires that:

• You must have an account on the remote system to log in.
• The NETMBX (network mailbox) privilege is set.

Format

SET HOST node-name

Parameter

node-name

Specifies the node name of the remote processor to which you will connect.

Description

The SET HOST command connects you to another processor on a network. (The SHOW NETWORK command lists the names of nodes accessible to your node.) Once the connection is made, the remote processor prompts for a user name and password. You must have an account on the remote processor to log in.

Once you have connected to the remote processor and have logged in, you can use DCL commands just as you would on your local processor. You can even use the SET HOST command to connect to another remote processor.

For example, if your local node is BOSTON, you can use the command SET HOST ALBANY to connect to the node ALBANY. You can then use the command SET HOST AKRON to connect (still through BOSTON and ALBANY) to the node AKRON.

Use the LOGOUT command to log out of the last processor you have logged in to and return to the previous processor. For example, when you use the LOGOUT command, you have logged out of (and disconnected from) the processor at node AKRON, but you are still logged in (and connected) to the processor at ALBANY. A second LOGOUT command logs you out of node ALBANY, and disconnects you from it. A third LOGOUT command logs you out of the local processor, BOSTON.

You can also abort operations and return directly to the original host processor, if necessary. Press Ctrl/Y at least two times in rapid succession. The following message is displayed:

Are you repeating ^Y to abort the remote session?

If you respond Y or YES, control returns to the original node. Other responses, such as N or NO, do not abort the connection. This technique is useful when you want to exit quickly without entering a series of LOGOUT commands, or when part of the network becomes disconnected and you want to return to the host.

Note that SET HOST, unlike the OpenVMS terminal driver, buffers output data from an executing program. Buffering improves performance in wide-area networks; however, in the case of programs providing output only, the buffering causes a discrepancy between what is happening in the remote program and what is displayed on the local terminal. That is, a program might finish executing before you see the output on the local terminal.

This discrepancy can be particularly confusing when you use the Ctrl/Y or the Ctrl/C function, or out-of-band abort characters to abort the execution of a program. For example, when you press Ctrl/Y or Ctrl/C (or enter out-of-band abort characters) during the execution of a captive command procedure, SET HOST immediately stops the display on the local terminal. It also aborts the current read and write operations and any pending write operations, including all buffered write operations.¹ Therefore, although it seems that the remote program aborts at the point in the program at which the display on the local terminal is stopped, the program might have executed beyond that point already---and might have finished executing---before you pressed Ctrl/Y.

Note that several SET HOST qualifiers, such as /MOP, /VTP, and /X29, are available only if DECnet-Plus is installed on your system. For information about using these qualifiers, type the following command:

$ HELP DECnet-Plus

Qualifiers

/APPLICATION_PROTOCOL[=protocol]

Specifies the protocol connection, CTERM (CTDRIVER) or RTERM (RTTDRIVER) on the specified node. CTERM protocol is the default if no connection is specified.

/BUFFER_SIZE=n

Changes the packet size of the protocol message sent between the terminal and the remote processor if a connection to the remote processor is already established. The default buffer size is 1010 bytes; however, the buffer size n can range from 140 bytes to 1024 bytes. The value of the parameter n is reset to 140 bytes if a value below 140 is specified; a value for n above 1024 bytes is reset to 1024.

You can force the host node to write to the terminal in smaller packets, thereby ensuring that write operations to the terminal are displayed at more frequent intervals, by setting n to a value just above the minimum of 140 bytes. On slow DECnet links, setting the buffer size to a smaller value may decrease pauses between write operations when large amounts of data are being scrolled to the screen.

/LOG[=filespec]

/NOLOG (default)

Controls whether a log file of the entire session is kept. If you use the /LOG qualifier without the file specification, the log information is stored in the file SETHOST.LOG.

/RESTORE

/NORESTORE (default)

Saves current terminal characteristics before a remote terminal session is begun and restores them when the remote session is terminated.

Examples

$ SET HOST/APPLICATION_PROTOCOL=CTERM DAKOTA
      

The /APPLICATION_PROTOCOL qualifier specifies the CTERM protocol (the default) on node DAKOTA in this command line.

$ SET HOST ITALIC
Username:  GRESO
Password: <PASSWORD>
    Welcome to OpenVMS VAX Version 7.3 on node ITALIC
   .
   .
   .
$  LOGOUT
GRESO logged out at 19-DEC-2001 15:04:25.27
%REM-S-END, Control returned to node _CASLON::

      

In this example, the name of the local node is CASLON. This SET HOST command connects the user terminal to the processor at the network node named ITALIC. The remote processor then prompts for user name and password. Use the normal login procedure to log in to the remote processor.

Once you are logged in at a remote node, you can use the SET HOST command to establish communication with another node. After logging in to node ITALIC, you could type SET HOST BODONI.

You would again be prompted for a user name and password. If you then supply a valid user name and password, you will be logged in to node BODONI.

Note that when you log out of node BODONI, control is returned to node ITALIC. You must log out of node ITALIC to return to your local node, CASLON.

$  SET TERMINAL/WIDTH=80
$  SET HOST/RESTORE GENEVA
Username: Jones
Password: <PASSWORD>
$  SET TERMINAL/WIDTH=132
   .
   .
   .
$  logout
JONES   logged out at 19-DEC-2001 11:04:51.45
%REM-S-END, control returned to node _ORACLE

      

This example shows user JONES on node ORACLE logging in to remote node GENEVA and specifies that the original terminal screen width be restored to 80 characters when the remote session is terminated.