Exchange/SNA Manual

Exchange/SNA Components
Introduction
104700 Tandem Computers Incorporated 1–7
The Line Server and the Programmatic Interface
The Exchange/SNA line server provides a programmatic interface. When you write a
program that uses Exchange/SNA, you use standard system procedure calls to
communicate with the line server. Your program passes records to and receives
records from the line server, which in turn handles the communications with the host
system.
Multiple Users
A single line server can be used simultaneously by several different Exchange/SNA
command interpreters and application programs. Each line server may have the
following number of openers:
Up to seven command interpreter openers
One opener for each defined console subdevice opener (the console subdevice can
have several openers)
One opener for each printer subdevice defined
One opener for each punch subdevice defined
One opener for each card-reader subdevice defined
Each line server can handle up to six data streams simultaneously—one data stream
for each LU defined. You may define up to six LUs per line server.
The Trace Server The Exchange/SNA trace server is a diagnostic tool that captures the messages
transmitted between the line server and the host system and records those messages in
a file called the trace file. You can then format and examine the contents of the trace
file to assist in program development and to determine the source of communication
problems.
You can use the trace server with both the command interpreter and the programmatic
interface. However, in both cases, you must start the trace server using the command
interpreter.