The Question is:
We want to use terminal port (TTA0: or TTB0:) to exchange data using our
private protocol. Of course we use QIO system services. The problem is when we
restart system (we install our software on AlphaStation 500). If second side
sends data to Alpha during
booting procedure, VMS grabs terminal port and runs LOGIN.EXE. So the second
side could see "Welcome to OpenVMS..."
How can we permanently grab terminal?
The Answer is :
In SYSTARTUP_VMS.COM, issue the DCL command:
SET TERMINAL/NOTYPEAHEAD/PERMANENT ddcu:
This will prevent any unsolicited terminal input on ddcu:, and
this unsolicited input is what triggers JOB_CONTROL to start up
LOGINOUT on the terminal. Once LOGINOUT starts up on the serial
line, you can see interesting behaviour (eg: audits, process
creations, etc) as LOGINOUT tries to "chat" with whatever device
is hooked onto the remote end of the serial line.