ZCOM Subsystem
ZCOM Concepts
Figure | Definition and Features of ZLUs |
Terminal 2
Terminal 1
Terminal | Terminal 3 |
ZLU=231 |
|
Terminal
ZLU=57
Terminal
ZLU=101
Mux card
Program
ZLU=500
Application
Program B
Program
ZLU=502
Application
Program A
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 to a queue that contains all messages, including timeout and status messages, that were delivered to the program ZLU. These pointers 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.
18 | Chapter 1 |