Martin,

> I compiled the VM for Linux from 3.1a sources and it gives me an
> option --enable-jit and the compiled executable has the options -jit
> and -spy, the latter of which I don't quite understand.

These are basically hooks for J3. I think --enable-jit just tries to
look for the jit entry point in the executable, -jit turns it on (if
present) and -spy gives status information in some X window.

> But my main question is: all these options have no noticable
> effect. Are these just blanks or is the jit up and running. Did I miss
> anything ?

Yes. You miss j3 ;-) It was never completely finished although the
version that were available worked quite well (there were a few issues
here and there). I don't remember the URLs but you should look at Ian's
site - there should be a tar ball for j3 somewhere.

> Is there a way I can tell that a jit is doing its work ?

Run "0 tinyBenchmarks". If those values don't go through the roof, it is
_not_ working (most likely not present).

> Also: The image will never contain compiled code, right ?

Right.

Cheers,
  - Andreas