Pessimistic STM

This paper may interest those who follow E and other event loop systems. 
Some recent results in the STM world indicate that single-threaded 
pessimistic STM is competitive with optimistic STMs due to the lower 
incidence of aborts and reduced thread sync required:

http://transact2012.cse.lehigh.edu/papers/matveev.pdf

Event loops are similarly single threaded due to the possibility of 
writes. A language that tracks side-effects could implement an E-style 
event loop and execute all enqueued read-only messages in parallel.

Sandro