Q1) Does anyone familiar with the Java Disruptor pattern know the size of messages they benchmarked their results against? I am writing a similar system (out of pure interest) and when I read the description of their testing there is no mention of the message size sent?
http://code.google.com/p/disruptor/wiki/PerformanceResults
Q2) Is the disruptor for computer to computer communications, or inter-process? I originally had the impression it was for computer to computer but their work is labelled "inter thread" messaging library?
Disruptor is not just within the same machine, it is withing a single process. When they say "inter-thread", they mean that it is for sending messages between threads of one process.
The message size is actually almost irrelevant because the messages don't get copied. The messages are all fixed at the beginning and reused, so it doesn't really matter how big they are.