  Serial Console Terminal Operations? 
 The Question is:
 
Hello Wizard,
 
I have two questions:
 
1) I have a VT420 connected to my server (server is a vax V5.5-1).
 The VT420 displays OPCOM messages besides the normal logging in to server.
If VT420 is spoilt (eg. no cursor showing), will this cause
my server (which is running applications) to crash? Why ?
If VT420 hangs but not spoilt, will my server crash?
Whether VT420 hangs or spoilt - are they two different situations?
If so, in what way are they different?
 
2) I have a printer connected to the VT420 (assuming VT420
is not spoilt). The printer prints system boot up messages and OPCOM
messages. If my printer jams
or becomes offline, will this in turn cause the server to crash?
How does the printer affect the server?
 
 
Thank you.
 
 The Answer is:
 
  Paper jams and other events which can cause an XOFF (a flow control
  signal) to be sent to the OpenVMS host from the console can cause the
  OpenVMS system to hang, waiting for the condition to be cleared.
 
  The OpenVMS Wizard would not generally expect these hangs to cause
  the OpenVMS system to crash, save for extreme resource starvation
  conditions in conjunction with the "crash" setting for the audit
  server.
 
  OpenVMS is generally completely oblivious to the display or settings
  on any serial line terminal, barring the reception of flow control
  signals from the terminal.  OpenVMS does not read back information,
  nor does it pay particular heed to the window or cursor settings.
  OpenVMS "merely" sends text for display on the terminal.
 
  If you are seeing system crashes, please directly contact the Compaq
  Customer Support Center for assistance in locating and resolving
  the failing software.
 
  You can disable OPCOM messages at the console using SYLOGICALS.COM
  or similar mechanism -- please see section DCL4 in the OpenVMS FAQ,
  though you would want to use REPLY/DISABLE for this purpose.
 
  The OpenVMS Wizard would recommend an upgrade to V5.5-2, or to V6.2,
  or to V7.1 or V7.2.  (Once you upgrade your OpenVMS VAX system to
  V6.0 or later, there is little reason not to upgrade to the current
  V7.2 release -- both the user-mode and the inner-mode environments
  are very similar in V6.0 and later, and few or no application problems
  are expected to be encountered, even with device drivers...)
 
