Exchange/SNA Manual

Step 4: Perform the Operation
Using the Exchange/SNA Command Interpreter
104700 Tandem Computers Incorporated 2–9
Sending Multiple Files. To send multiple files to the host as a single stream of data, use
the SEND command with the END DEFER parameter. This suppresses the sending of
an end-of-file character to the host at the end of the send operation. A separate SEND
command is then used to send each separate file to the host. Each SEND command
must use the same subdevice. All SEND commands must also use the END DEFER
parameter, except for the last SEND command. The last SEND command must use the
END IMMED parameter, which sends an end-of-file character to the host and indicates
the end of the data stream.
Note that when sending multiple files as a single data stream, the first SEND
command determines the values for the COMPRESS and RECSIZE parameters. All
subsequent SEND commands in the same data stream should contain the values
specified in the first SEND command.
If you specify a different COMPRESS parameter, you receive a warning message. You
also receive a warning message if you specify the COMPRESS parameter in the first
SEND command, but eliminate the value in a subsequent command.
If you specify a different RECSIZE parameter, the records are sent to the host as
specified within each SEND command. However, the host uses the record size
specified by the first SEND command. If a subsequent RECSIZE parameter is greater
than the original RECSIZE parameter, the host may split the records; you do not
receive a warning message when this happens.
Receiving Files
Each RECEIVE command uses a particular printer or punch subdevice. When you
specify a particular subdevice in a RECEIVE command, you are specifying that you
want to receive the data from the host whose destination is that subdevice. For
example, if the host has the output of a job ready to send whose destination is printer
unit number 1, you must specify printer subdevice unit number 1 in the RECEIVE
command to receive that file.
In general, the host system assigns a destination subdevice to each file spooled for
output. To receive a given file, you must execute a RECEIVE command that uses the
destination subdevice specified by the host for that file. The destination subdevice is
identified in the media and subaddress fields in the type 1 function management
header that begins the flow of data from the host. You can use host RJE subsystem
commands to list and control the files spooled for output and their destination
assignments. See the host RJE subsystem documentation for information on host RJE
subsystem commands.
The RECEIVE command can be used to receive a single file from the host or to receive
several files from the host with the same destination subdevice. The following
paragraphs briefly describe each use of the RECEIVE command. For more information
on the RECEIVE command and its parameters, see Section 3.