I've seen two systems that deal with a huge volume of data where parallelism, speed and throughput were critical. One was a mobile network operator call billin

I've seen two systems that deal with a huge volume of data where parallelism, speed and throughput were critical. One was a mobile network operator call billing system, the other one a stock exchange. First one was written in C, the second one I'm not certain, but my understanding is that it was C too.