Serial console: Ctrl-C doesn't work
Bernd Dammann
[ Author was Bernd Dammann ]
[ Posted on 9 Jun 2000 08:33:19 GMT ]
Hi,
I've set up a diskless and headless machine with a serial console that
I access from the server through a null-modem cable (using kermit as
terminal emulator). Everything works fine, except for one thing:
Ctrl-C (intr) and Ctrl-Z (susp) don't work! All other Ctrl- sequences
like Ctrl-U (kill) and Ctrl-W (werase) do work.
Where is the problem? The console settings (see below), or the
terminal emulation? I've tried several terminal emulation programs
(i.e. kermit, minicom, ...), but the problem is the same.
Here are the console stty settings:
speed 38400 baud; rows 24; columns 80; line = 0;
intr = ^C; quit = ^\; erase = ^H; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W;
lnext = ^V; flush = ^O; min = 1; time = 0;
-parenb -parodd cs8 hupcl -cstopb cread clocal crtscts
-ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff
-iuclc ixany -imaxbel
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig icanon -iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt
-echoctl -echoke
TERM is set to vt100.
Any hint? TIA,
Bernd
--
# Bernd Dammann <be...@fki.dtu.dk> | "Why stop now,
# Department of Physical Chemistry | just when I am hating it?"
# The Technical University of Denmark |---------------------------------
# Building 206 | phone: (+45) 45 25 24 81
# DK-2800 Lyngby, Denmark | http://www.fki.dtu.dk/~bernd/
--
# Bernd Dammann <be...@fki.dtu.dk> | "Why stop now,
# Department of Physical Chemistry | just when I am hating it?"
# The Technical University of Denmark |---------------------------------
# Building 206 | phone: (+45) 45 25 24 81
# DK-2800 Lyngby, Denmark | http://www.fki.dtu.dk/~bernd/
Frank da Cruz
Bernd Dammann <be...@lipid.fki.dtu.dk> wrote:
: I've set up a diskless and headless machine with a serial console that
: I access from the server through a null-modem cable (using kermit as
: terminal emulator). Everything works fine, except for one thing:
:
: Ctrl-C (intr) and Ctrl-Z (susp) don't work! All other Ctrl- sequences
: like Ctrl-U (kill) and Ctrl-W (werase) do work.
:
: Where is the problem? The console settings (see below), or the
: terminal emulation? I've tried several terminal emulation programs
: (i.e. kermit, minicom, ...), but the problem is the same.
So it's evidently something with your Linux configuration, having nothing
to do with the terminal emulator.
: Here are the console stty settings:
:
: speed 38400 baud; rows 24; columns 80; line = 0;
: intr = ^C; quit = ^\; erase = ^H; kill = ^U; eof = ^D; eol = <undef>;
^^^^^^^^^
: eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W;
: ^^^^^^^^^
These are set right. Nothing is obviously (to me) wrong.
Perhaps the problem is on your "server", whatever you mean by that. If you
start Kermit on your server, then at the C-Kermit> prompt, what happens if
you type Ctrl-C? If you see:
C-Kermit> ^C...
C-Kermit>
this means C-Kermit sees your Ctrl-C, and therefore when in CONNECT mode it
would also pass it along to the other computer, just as it would any other
character except its escape character (normally Ctrl-\), which must be entered
twice to send one copy. If you don't see "^C..." this means that something on
your server is filtering it out before Kermit gets it.
- Frank
Bernd Dammann
: In article <8i7c8n$11ro$1...@news.net.uni-c.dk>,
: Bernd Dammann <be...@lipid.fki.dtu.dk> wrote:
: : I've set up a diskless and headless machine with a serial console that
: : I access from the server through a null-modem cable (using kermit as
: : terminal emulator). Everything works fine, except for one thing:
: :
: : Ctrl-C (intr) and Ctrl-Z (susp) don't work! All other Ctrl- sequences
: : like Ctrl-U (kill) and Ctrl-W (werase) do work.
: :
: : Where is the problem? The console settings (see below), or the
: : terminal emulation? I've tried several terminal emulation programs
: : (i.e. kermit, minicom, ...), but the problem is the same.
: :
: So it's evidently something with your Linux configuration, having nothing
: to do with the terminal emulator.
You are right, I found out what went wrong:
Linux has the following devices
crw------- 1 root root 5, 1 Jun 16 16:32 /dev/console
crw------- 1 root tty 4, 64 Jun 14 17:15 /dev/ttyS0
and I had set up getty on /dev/console (which worked for me before on
an older Linux system (kernel < 2.0):
con:2345:respawn:/sbin/getty console DT38400 vt100
The right thing to do is:
con:2345:respawn:/sbin/getty ttyS0 DT38400 vt100
since /dev/console is a device for its own in newer Linux systems.
That solved the problem.