when x process isn't running... do something

[Bart Nessux]

Bart Nessux wrote:
> Howdy,
> 
> I'm trying to time how long it takes dd to run on a G5, versus how long 
> it takes to run on a G4 (PATA vs. SATA). Both sytems have Mac OS X 
> 10.3.2 and Python 2.3. Could someone demonstrate how I might use Python 
> to monitor for the presense of a process and to do something (in this 
> case send an email which I know how to do) as soon as that process is no 
> longer present? Any suggestions on how to monitor? Call top every 5 secs 
> and read it's output searching for 'dd'???
> 
> TIA,
> Bart
> 

I forgot to mention the fact that I already know when the process began. 
All I need to know is when it ends and then I can calculate the part in 
between those two points.