ACC Programmer's Reference Guide

18 Chapter1
ZCOM Subsystem
ZCOM Concepts
Figure 1-3 Definition and Features of ZLUs
To communicate to another program or to a terminal, a program uses
ZCOM library calls to write to a program or terminal ZLU. Each program
ZLU points t o a queue that contains a ll messages, including timeout and
statusmessages, that were delivered to the program ZLU. Thesepointers
are maintained automatically by the ZCOM Subsystem. When a message
is sent to a ZLU, the data is moved to a system buffer first and the
address of the message is moved to the attached input queue.
Application
Program A
Application
Program B
Ter minal 1
Ter minal 2
Ter minal 3
Mux card
Program
ZLU=502
Program
ZLU=500
Ter minal
ZLU=101
Ter minal
ZLU=231
Ter mi na l
ZLU=57