Re: same output display repeatedly

[Ed Blackman]

On Tue, Mar 16, 2010 at 07:34:23PM -0400, Software Groups wrote:
> I was using screen on solaris for few year with any issue. Recently I
> have moved to Redhat Linux 4 its running under vmware.  Whenever
> command displays more lines of output (like cat, dmesg etc), same
> output scrolling repeatedly on that window, I have to kill that window
> and re-open the connection to remote host.

Are you sure this only happens in screen?  I experienced a problem with 
the same symptoms years ago when I had a primitive VPN that was setting 
the MTU to be higher than the link could actually support.  If this only 
occurs in screen, then ignore the following.

Check out http://en.wikipedia.org/wiki/Maximum_transmission_unit and 
note the sentence "One often detects such blocking in the cases where a 
connection works for low-volume data but hangs as soon as 
a host sends a large block of data at a time".

You can test this with a short Perl command line.  Run this on the 
remote system while connected to the remote host directly (not in 
screen):
  perl -e '$| = 1; $i = 0; while($i++ < 10000) { print "\n$i\n"; print("A" x 
$i); sleep 1; }'

If it gets all the way to 10000 (note, it will take almost three hours 
to do so), your network is configured correctly.  If it hangs, it will 
have printed the number that is one more than the actual largest packet 
size on that link.  You can then describe your symptoms, network 
configuration, and the perl test on a Redhat list and should be able to 
get help with configuring your network so the above test will pass.

Ed

signature.txt
Description: Digital signature