OS X Mavericks :: Terminal Utility Window Go To Sleep

One issue though is that occasionally, a terminal utility window will go to sleep (or become Zombified) and won't wake up again.

This happens when I am running a long numerical calculation from one of the tabs in the terminal window. 

Normally, the numerical calculation does not print much, but will occasionally print out information about the progress of the program and sometimes error messages.  In past MAC-OSX, I had just started the numerical calculation in one tab and went on working (vim editing e.g.) in another tab in the same window, occasionally going back to check for error messages and progress. 

In Mavericks OSX though at some point, the long run-time of the numerical calculation causes the whole terminal window to sleep including the tab in which I am doing the editing. 

It is an interesting sleep.  The numeric calculation keeps running, so I just set the window aside to let the program finish. 

Other terminal utility windows are fine but all tabs on the same window are in the sleep mode.

The sleeping windows can actually be updated to their most recent, directly visible content by hitting the yellow dot at the top left,

sending the window down to the Dock, and then reopening from the Dock.

Even after reopening the terminal window from dock, the whole window (every tab) remains asleep. Scrolling does not work, continued updating of the screen output by the numerical calculation does not work, but you can see the most recent content by using the Dock update trick. 

I can work around this and change the numerical calculation to send the output and error messages to a file instead of the screen and then run the programs in background.  (Don't know if background programs will still zombify the terminal window.)

Also, I can do the editing from a separate terminal window, but at first the unexpected irreversible sleep caught me off-guard.   

I realise that such automatic sleeping might be part of the reason for the large increase in speed, which is actually more important to me than maintaining the viability of each terminal window. 

I am wondering though if there is some way to reanimate the sleeping terminal windows to inspect error messages more easily (i.e. scroll up to old ones).