Reports of Perl 6 in production are slowly trickling in on the #perl6 IRC channel, but currently it's only a handful. Even I as a Perl 6 compiler developer don't recommend its production usage yet. But for learning the language and small one-off tasks it's already very nice, and getting nicer each month.

http://moritz.faui2k3.org/tmp/perl-cake.jpeg

I've worked two years on a PHD thesis involving all-optical signal processing (though I worked on all-optical signal regeneration, not logical gates), and one of my conclusions is that multi-level is an order of magnitude more challenging than two values. The reason is that if you do multiple processing steps, you usually get some random fluctations, so you need to have components that fix that, i.e. fix to a certain level. Now you have basically two options, you can encode your information in the phase or in the amplitude/power. In the case of power levels you can use something like nonlinear loop mirrors, but they have the problem that they change the power ratio level between the states. In the case of phase encoded signals, a you can use a saturated phase-sensitive amplifier (for example two symmetric pumps), but they require quite high powers, and you have to injection-lock the pumps to compensate phase drifts, and they still only work for two levels. There is exactly one scheme that works for multiple levels (see http://eprints.soton.ac.uk/336325/1.hasCoversheetVersion/Thesis.pdf for a PHD thesis about it), but it turns phase noise into amplitude noise, so you need an amplitude regenator after it. So, binary logic is plenty of challenge to get working; once that's establish, we can still think about multiple levels.

The US would have to prove ownership first, thus authenticating the leaked documents. Not quite what they want, is it?

I'm pretty sure there is room for both techniques. For irrigation you don't need the same quality as for drinking.

I know several persons who have drastically outlived their medical prognosis; none of them seem particularly driven compared to Hawking (but they do all enjoy to live). So the question is, are those predictions too pessimistic, or have all the other people with bad predictions died, and I can't meet them anymore?

To quote the paper on arxiv: The measurement also relies on a high-accuracy geodesy campaign that allowed measuring the 730 km CNGS baseline with a precision of 20 cm.

would have been much cheaper than a law suit, with the same effect :-)

The Perl community has more advent calendars than the one linked in TFA:

• Perl 6 advent calendar
• Catalyst advent calendar
• Perl Dancer advent calendar
• Plack advent calendar
• Uwe's CPAN advent calendar
• Ricardo's Perl advent calendar

(Catalyst, Plack and Dancer are web frameworks)

Good thing that Perl is dead. Just imagine how it'd overflow the internet with advent calendars if it were alive!