Re: Serial Connection -- shielding
Le 01/04/11 01:51, Stephen Powell a écrit :
Sorry forgot to mention that we are in Paris and the datacenter is in
Amsterdam. So no physical access to the servers.
On Thu, 31 Mar 2011 09:14:07 -0400 (EDT), MAROUNI Abbass wrote:
In a production environment, this what will happen :
Two servers connected with a single serial cable ( Which I need to
figure out how?! :) ), ttyS0 on server1 to ttyS0 on server2.
getty is always listening to the ttyS0 port on both servers (assured by
Server1 is inaccessible. login to server2 launch a script that will kill
getty and comment its entry from inittab then launch minicom toward
ttyS0 on server1 login to server1 and find what happened. Finally on
server2 quit minicom launch another small script that would put getty on
ttyS0 and uncomment its entry from inittab. This way if something wrong
happens to server2 I am sure that I have a getty on its ttyS0 and all I
need to do is to go to server1 follow the same procedure.
Reverse communication assured :)
Logical isn't? :)
I am still not convinced that the serial cable might have different ends
if it's a standard null modem cable, so I don't think that reversing the
ends between the two servers might help.
OK, now I think I understand. I have some more thoughts, but before I
share them I want to address your attitude.
Suppose you were a medical doctor. Suppose I came to you with a problem.
For the sake of example, let's say that I am complaining of a sore throat.
You use a tongue depressor and a flashlight and look at the back of my
throat. It's deep red and very swollen. You take my temperature. I have
a fever. You think the problem is strep throat. So you write me a
prescription for an antibiotic. I thank you and leave your office. Three
days later I come back in, complaining that my throat is worse than
before. You ask me if I have been taking the medicine that you prescribed
according to directions. I say, "No, in fact I didn't even bother to
fill the prescription." What would your reaction be? How motivated would
you be to continue trying to help me? I dare say, not very motivated.
If I had taken the medicine but the problem grew worse, you would be
even more motivated to help me. But if I wouldn't even try what you
suggested, I dare say your reaction would be, "Fill the prescription
and take the medicine according to my directions. If you don't feel
better in three days, come back and see me."
You are acting just like that. People ask you for specific information.
You don't provide it. Someone suggests that you try something, but you
don't try it because "you don't think" that that is the problem. Well,
if you're so smart, why are you asking for help? How hard is it to reverse
the cable, for diagnostic purposes, just to see if it makes a difference?
You won't try anything. Now I have an idea of what the problem might
be. It might be the solution. Or I might be barking up the wrong tree.
But I'm not going to share it with you until you try what I've already
Reverse the cable and see if makes any difference. Let me know the
results of the experiment. Then maybe I'll suggest something else to try.
But good news : I finally made it.
Apparently ttyS0 and ttyS1 are different. I had to use baudrate of
115200 with vt102 on ttyS0 and a bauderate of 9600 with vt100 on ttyS1.
is that a software or a hardware issue? I always thought that ttyS0 and
ttyS1 are the same.
Thanks for you all. Much appreciated.
Internet Memory Foundation