Is there a unique ID associated with each task?

[Joel Welling]

Hi folks;
  I'm writing a Hadoop Pipes application, and I need to generate a bunch
of integers that are unique across all map tasks.  If each map task has
a unique integer ID, I can make sure my integers are unique by including
that integer ID.  I have this theory that each map task has a unique
identifier associated with some configuration parameter, but I don't
know the name of that parameter.
  Is there an integer associated with each task?  If so, how do I get
it?  While we're at it, is there a way to get the total number of map
tasks?

Thanks,
-Joel