Created attachment 257982 [details]
Shows how the terminal truly freezes

What Was Expected:
gnome-terminal would simply display output until program terminated or ended.

What Happens:
When running an application in terminal, either as a launcher or simply opening a terminal directly , the screen output randomly freezes and the generating / running application freezes. To resume, one must double-click the open terminal window and/or use terminal reset & clear. Some type of user input seems to resume. The problem makes running almost any application with terminal screen output unusable and unstable--for example, running a machine learning algorithm. Note, by freeze I mean the terminal output itself freezes--the terminal window remains active (buttons and menus work) as do all other applications. The screen output simply freezes.

The problem affects both mate-terminal and gnome-terminal. The bug does not affect a simple x-terminal instance. xterm and uxterm are not affected and are a temporary kludge to get around the issue.

Affected Applications:
gnome-terminal
mate-terminal
but not xterm or uxterm.

Because of the random character, this is a real problem. For example, running a machine learning algorithm or modelling system becomes impossible to run reliably using gnome-terminal or mate-terminal. (For example, you set a batch to run over night and return to find the terminal output frozen only ten minutes after you left for the evening.) The only workaround I have found, using a desktop, is using xterm or uxterm instead.

Test Code:
The following simple Python3 code demonstrates the issue.

----BEGIN CODE----
import time
starttime = time.time()
i = 0
while(True):
    i = i + 1
    print("Still working " , i, " " , time.time() - starttime)
---END CODE---
When running this code in a mate-terminal or gnome-terminal instance, the code displays a simple message along with the time. After a random period, sometimes seconds, sometimes minutes, sometimes hours the bug arises and the terminal instance screen simply freezes. That is, display output just stops in mid-stream. You can resume but only by double-clicking or using reset & clear. apparently, some type of user input is required to continue running. after user input, the application resumes as if nothing happened.

Bug can arise at any time. I have seen the bug arise after a few seconds, about ten minutes, or after six hours. NOTE: I have extensively tested this over a period of several weeks. The freezing /stopping is truly random. 

The bug affects at least Python and Java applications that display output  to the terminal.

Approximate Number of Tests:
Well over 50 and narrowed the issue to the terminal instances.

Hardware:
i7 4770
32GB RAM
(new) Nvidia 760 Video (note: the problems occurs with Nouveau or any proprietary Nvidia driver versions 3.04 through 3.25, that is, all were tested to see if this was just a video driver issue and none resolved the issue)

OS:
Ubuntu 13.04 (with all updates)
Ubuntu 13.10 (with all updates)

Desktops:
Confirmed the bug occurs under Ubuntu Default/Unity, GNOME3, and MATE desktops. Same odd error in all.

13.04
apt-cache policy gnome-terminal
gnome-terminal:
  Installed: 3.6.1-0ubuntu4
  Candidate: 3.6.1-0ubuntu4
  Version table:
 *** 3.6.1-0ubuntu4 0
        500 http://us.archive.ubuntu.com/ubuntu/ raring/main amd64 Packages
        100 /var/lib/dpkg/status

apt-cache policy mate-terminal
mate-terminal:
  Installed: 1.6.1-1.1+raring
  Candidate: 1.6.1-1.1+raring
  Version table:
 *** 1.6.1-1.1+raring 0
        500 http://packages.mate-desktop.org/repo/ubuntu/ raring/main amd64 Packages
        100 /var/lib/dpkg/status

13.10
apt-cache policy gnome-terminal
gnome-terminal:
  Installed: 3.6.1-0ubuntu6
  Candidate: 3.6.1-0ubuntu6
  Version table:
 *** 3.6.1-0ubuntu6 0
        500 http://us.archive.ubuntu.com/ubuntu/ saucy/main amd64 Packages
        100 /var/lib/dpkg/status

apt-cache policy mate-terminal
mate-terminal:
  Installed: 1.6.1-1.1+raring
  Candidate: 1.6.1-1.1+raring
  Version table:
 *** 1.6.1-1.1+raring 0
        100 /var/lib/dpkg/status

Also Reported:
Originally, I thought there was sme type of buffer being filled. See http://forums.mate-desktop.org/viewtopic.php?f=2&t=2005&p=6899#p6899 and especially notation that at least one other app exhibiting similar behaviour. Quote: "Terminator (fork of Gnome-Terminal) under another user account where htop would freeze and only resume when user input was encountered (clicking the tasks)." 

Originally, I thought this was a Ubuntu-specific issue and reported at https://bugs.launchpad.net/ubuntu/+source/gnome-terminal/+bug/1234453 .

I also heavily tested video card options (thinking this might be a video issue but I am less inclined to think that is the source due to testing.