Chapter 4: Reuse device and database configurations

Follow the lessons in order; keep the application source for later exercises.

• Move device configuration into an iocshLoad fragment.
• Run independently configured request/reply simulators.
• Configure three device connections in one IOC.
• Stream 32 temperature channels from one simulator.
• Load records directly, at build time, or with substitutions.
• Explain the startup sequence and linked libraries.
• Read the Base initialization sequence.
• Locate each complete runnable example.

Chapter exercises

1. Copy the Chapter 3 st.cmd to st_break.cmd. Move iocInit() immediately before dbLoadRecords, start it, and inspect the startup error. Restore the original order and confirm normal communication.
2. In lesson 4.5, configure two TC32 simulators and verify all 64 PVs.
3. Explain which macros are resolved at build time and which remain for startup. Generating a flat database changes where expansion happens; it does not establish a measured startup-time advantage.

Before moving on

• jeonglee_Demo/ retains iocsh/training_device.iocsh, simulator/advanced_connection_handler.sh, and simulator/tc32_emulator.bash for Chapters 5 and 6.
• jeonglee_Demo/db/TC-32.db is rebuilt from restored sources so head -n 7 db/TC-32.db shows $(P)$(R)CH01 and $(PORT).
• Every jeonglee_Demo IOC is stopped with exit and every simulator is stopped with Ctrl+C.
• ss -ltn 'sport = :9399 or sport = :9400 or sport = :9401' reports no active TCP listeners.