TOPS-20 Commands Reference Manual
Connects your terminal to another system.
@SET HOST node-name:: /switch
(Omitting the node name on the command line allows you to define an interrupt sequence)
@SET HOST /switch Two character interrupt sequence (^\,<RET>): interrupt-sequence Node name: node-name::
|node-name::||is the name of the remote host that you want to connect your terminal to. Two colons (::) following the node name are optional.|
|/switch||is an optional keyword that selects the service used to connect your
terminal to a remote node.
Default - /CTERM
|interrupt-sequence||is the characters that switch control of the terminal back to the local
host. You are prompted for an interrupt sequence only if you give the
Default - CTRL\,<RET>
SET HOST Command Switches
|/CTERM||connects your terminal to the remote node by running the CTERM
communications program. Both processors must be running DECnet Phase 4
software (available under a separate license). The SET HOST command runs
the CTERM communications program by default. If the remote node does not
support the CTERM protocol, SET HOST attempts the connection again. In the
second attempt however, SET HOST runs the communications program defined by
the logical name NRT: (Network Remote Terminal).
|/NRT||runs the communications service program defined by the logical name NRT: (Network Remote Terminal). NRT: can be a system or job logical name. When both exist, the job definition takes precedence.|
Logging into the Remote Node
Once your terminal is connected to the remote node, the system responds by identifying itself and prompting you to log in. You can then log in to the system.
Path of Terminal Input and Output
The SET HOST command passes terminal input through the local host to the remote host. Output from the remote host passes through the local host to your terminal.
Making a Series of Host Connections
Once you have logged in to a remote node, you can give EXEC commands and run programs just as you would on your local node. You can then establish a connection to another remote node. For example, if your local host is AURORA, you can give the command SET HOST BOSTON to connect to the node BOSTON; after logging in to BOSTON, you can use the command SET HOST DENVER to connect to node DENVER.
Returning to Your Local Host
To return your terminal to your local host, type the interrupt sequence to temporarily break the connection to the remote host. Note that the connection to the remote host remains intact until you reset the CTERM program. You can reconnect your terminal to the remote host by giving the CONTINUE command.
When you log out of the remote host, the connection is broken and you are returned to your local host.
If you have established a series of connections, the interrupt character defined in your first SET HOST command returns you to your local host. For example, your local host is AURORA and you SET HOST to BOSTON, specifying the CTRL\<RET> interrupt sequence to return to AURORA. Then from BOSTON you connect to DENVER. Typing the CTRL\<RET> interrupt to DENVER returns you to AURORA, not BOSTON.
Specifying the Interrupt Sequence
- The interrupt sequence can be a combination of two characters or control characters. For example, KL ^KL, K^L, and ^K^L are valid interrupt sequences.
- If you specify only one interrupt character, the second character is ^J. For example if you specify only ^N as the interrupt sequence, the actual interrupt sequence is ^N^J. If you type only F, the interrupt sequence is F^J.
- Each interrupt character must be different. For example, ^K^K is invalid, while ^KK is a valid interrupt sequence.
- Do not type a comma or a space between interrupt characters as it will be interpreted as the second character in the sequence.
- The RETURN key can only be used in the default interrupt sequence, ^\<RET>.
- The interrupt sequence cannot contain predefined TOPS-20 control characters. For example, if you attempt to specify an interrupt sequence as ^T^I, the ^T will print the run status and the ^I will print a tab. See Appendix D in this manual for a list of TOPS-20 control characters.
Controlling Scrolling on a Remote Host
On your local host, <CTRL/S> and <CTRL/Q> are the default control characters that pause and continue scrolling. Typing <CTRL/Q> continues scrolling whether scrolling paused because you typed <CTRL/S> or the output paused on an end-of-page.
However, CTERM does not pass these characters to the remote host. When using <CTRL/S> and <CTRL/Q>, it is the local host that actually controls scrolling. Therefore if output from the remote host has paused on an end-of-page, <CTRL/Q> will not continue scrolling. Other pause and continue characters are passed to the remote host. You can use <CTRL/A> to both pause and resume scrolling or you can use the TERMINAL PAUSE command to assign any two characters of your choosing to control scrolling. For consistency, it is recommended that you define the same pause and continue characters on your local and remote node.
Listing Available Nodes
Use the INFORMATION DECNET command to display the names of DECnet nodes accessible to your node.
Effect on Terminal
The SET HOST command connects your terminal to the remote system. After the remote system's herald message is printed, you can log in.
|CONTINUE||for resuming a connection that was broken with an escape sequence.|
|INFORMATION DECNET||for displaying the names of nodes reachable from your node.|
|INFORMATION JOB-STATUS||for displaying the name of the host node and other information about your job.|
|INFORMATION LOGICAL-NAMES NRT:||for displaying the name of the communications program run by /NRT.|
|SYSTAT||for displaying (in the ORIGIN column) the name of the local system (the system you connected to before connecting to the current remote system).|
- Connect your terminal to a remote TOPS-20 node named AURORA and then
@SET HOST AURORA [Attempting a connection, connect OK, ] [Remote host is a TOPS-20 system] [TYPE ^\,<RET> to return to node ROMAX] AURORA - Claims Tracking System, TOPS-20 Monitor 7(21002) @LOGIN RSMITH Job 4 on TTY315 15-Nov-87 09:35:03, Last Login 15-Nov-87 08:18:48
- Give the INFORMATION DECNET command to find out if node BOSTON is
reachable from your host node. Then give the SET HOST command without
typing the node name on the command line. Omitting the node name causes
the system to prompt you for an interrupt sequence. After typing your own
interrupt sequence, the system prompts you for the name of the remote node.
@INFORMATION DECNET BOSTON Node BOSTON is reachable @SET HOST Two character interrupt sequence (^\,<RET>): ^ED Node name: BOSTON [Attempting a connection, connect OK, ] [Remote host is a TOPS-20 system] [TYPE ^E,D to return to node AURORA] BOSTON, AI Engineering Center, TOPS-20 Monitor 7(21002) @
- Connect to a remote node named TEAL. After logging in and doing some
work on TEAL, type the ^\<RET> interrupt sequence to return to your
@SET HOST TEAL [Attempting a connection, connect OK, ] [Remote host is a TOPS-20 system] [TYPE ^\,<RET> to return to node FLYWAY] TEAL - Migratory Bird Banding, TOPS-20 Monitor 7(21002) @LOGIN LOWELL Job 4 on TTY315 15-Nov-87 09:35:03, Last Login 15-Nov-87 08:18:48 . . ^\<RET> (Interrupt sequence not displayed on terminal) [Connection interrupted, back at node FLYWAY, Type CONTINUE to resume connection]
After working on node FLYWAY, type the CONTINUE command to reconnect your terminal to node TEAL. Then give the INFORMATION JOB-STATUS command to verify that you are connected to TEAL.
@CONTINUE @INFORMATION JOB-STATUS Host TEAL Job 17, TTY4, User LOWELL, REPORTS:<LOWELL> Account 341
- Attempt a connection using the CTERM program. The system attempts the
connection and finds that the remote node does not support CTERM. It then
attempts another connection using the program defined by NRT:
@SET HOST ROMAX [Attempting a connection, Connect failed - Host did not accept CTERM connection, trying NRT: [Attempting a connection, connect OK] [Remote host is a TOPS-20 system] [TYPE ^P to return to node AURORA] ROMAX - Acme's Timesharing System, TOPS-20 Monitor 7(21002) @