Re: OPA0 Console connection

In article <ops6diokhnzgicya@hyrrokkin>, "Tom Linden" <tom@xxxxxxxxxx> writes:
:Let me summarize what I have undercovered so far.
:
:firstly the COM1 port seems to be named TTA0 and the COM2 OPA0.
:Why not just call them COM1 and COM2?

Well, you can call them anything you want, of course. OpenVMS
has always called the console port OPA0:, meaning -- if we changed
it -- we'd tend to bust stuff. (And we tend not to like to do
that when we can avoid it.)

Even more interesting, COM1 and COM2 don't always map the same
way, as these can be an OP device or a TT device based on the
system firmware configuration.

:If you need to use the other names, make them an alias.

What's an "alias", in this context?

If I wanted other names for a device, then I would tend to define
site-specific logical names for the constructs -- but to define
these tends to cause as many problems as it solves, as we learned
back in MicroVAX days. (Do see the MICROVAX subroutine within
SYLOGICALS.TEMPLATE.) We still define these old logical names,
as there is stuff around that still uses them -- but the names
don't scale particularly well, and users and programmers then
eventually tend to use logical names or such to implement the
required mapping for the particular application requirements.

Things are really getting interesting with devices and device
naming and such, but that's fodder for another discussion --
and maybe one at the bootcamp.

:Secondly, suggested remedy in the FAQ, in fact
:disables login from that port, so that is not the right approach.

It is the correct approach. You have to disable the typahead to avoid
the bouncing logins, and you need to enable it to get the login -- and
having two ports back-to-back means you have to choose which one is the
one that will originate, and which will receive the connection.

So how to leave a console cable attached without crashing the system is
:still not solved. BTW if I leave it attached to a W2K problem does not
:occur.

You just haven't seen the problem yet. Anything that can or does
generate a framing error on the line will trigger the halt.

My preference here is a terminal server, as it does what you want,
and you can (relatively) secure it against unauthorized access,
and you don't need to worry about which end of the connection is
the initiating and which is the receiving. (The terminal server
always initiates the connection to the console, meaning you don't
have to worry about folks connecting into it.)



---------------------------- #include <rtfaq.h> -----------------------------
For additional, please see the OpenVMS FAQ -- www.hp.com/go/openvms/faq
--------------------------- pure personal opinion ---------------------------
Hoff (Stephen) Hoffman OpenVMS Engineering hoff[\0100]hp.com

.

Relevant Pages

  • Re: EFI is out to lunch
    ... > error (something has destabilized the firmware), ... > The consoles on I64 can have more than one connection, ... > another line acquire and access the console. ... The MP provides a serial port, a web port, and up to 15 ...
    (comp.os.vms)
  • Re: Connecting to a Cisco router via console port.
    ... alot of people are asking how to connect to a console ... port, and console port via USB, console port is easy using minicom, ... but they have console to USB adapters which I can't connect. ... legacy port) boxes - well I would try a direct USB connection first ...
    (Ubuntu)
  • Re: Using VT420 as Alpha System Console
    ... :port 1 - the right-hand one. ... COM1 is the console serial port when the CONSOLE environment ... Com1 is the upper PC-style DB9 connection, ...
    (comp.os.vms)
  • Re: Serial console connection problem
    ... fstat shows nothing on the port; ... The last one (console) does not appear on the 5.3 machines processlist, ... would it be safe to kill that one just like that with kill -9 238 (If ... The connection is ordinary serial cable, do you mean that should specify ...
    (freebsd-questions)
  • Re: Correction
    ... Normally to physically disconnect is just a matter of reaching for the ... >> I have an ADSL connection which polls my computer from time to time, ... > disallow each and every port with Windows Firewall? ...
    (microsoft.public.windowsxp.messenger)