Exchange/SNA Manual

Step 4: Perform the Operation
Using the Exchange/SNA Command Interpreter
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The line server to host LU-LU sessions remain as long as the line server remains. An
Exchange/SNA line server maintains a continuous connection with the host system.
None of the sessions are terminated until the line server is stopped. To stop the line
server, use the STOP command.
When a line server is started, it records the accessor ID (user ID) of the command
interpreter that started it. Thereafter, any command interpreter with the same accessor
ID is said to be privileged with respect to that line server. Certain Exchange/SNA
commands, such as the STOP command, require that the command interpreter be
privileged with respect to the line server to execute the command. The individual
command descriptions in Section 3 identify those commands that require a privileged
command interpreter.
Connecting to an Existing Line Server
When you use the CONNECT command to establish a connection with an existing line
server, you must specify, in the NAME configuration parameter, the line server you
want to use. If you use the CONNECT command with the exclamation point
(CONNECT !), you do not need to specify any other configuration parameters. See
Step 2 for more information on the configuration parameters.
When connecting to an existing line server, you are connecting to an established set of
LU-LU sessions with a particular host system. You cannot change the configuration of
the line server or alter the connection with the host system.
The main advantage of using existing line servers is that it avoids the overhead of
starting a new line server and establishing the LU-LU sessions with the host system
each time you want to communicate with the host system.
Step 4: Perform the
Operation
This is the step where you communicate with the host system. This step can consist of
sending files, receiving files, or both. Additionally, this step can include sending
commands to the host RJE subsystem and receiving any output produced by the
commands.
Sending Files
Each SEND command uses a particular card-reader subdevice (the subdevice specifies
the source of the data sent to the host). The card-reader is identified to the host by the
media and subaddress fields in the type 1 function management header that begins the
flow of data to the host.
The SEND command can be used to send a single file to the host or to send several
files to the host as a single stream of data. The following paragraphs briefly describe
each use of the SEND command. For more information on the SEND command and
its parameters, see Section 3.
Sending a Single File. To send a single file to the host, use the SEND command with the
END IMMED parameter. This sends an end-of-file character to the host at the end of
the send operation.