stimulating reply about the convolution of the competition for the shared resources in the external state machine.
Apparently the concurrency problem is potentially convolved with external state in much more convoluted and intertwinded spaghetti: http://lambda-the-ultimate.org/node/2048#comment-51673 http://lambda-the-ultimate.org/node/3637#comment-51649 Multi-core is coming! Wouldn't it be better if the mainstream scripting (i.e. composability) language was also pure FP (and the composable modules were pure FP). If it costs 4X slower (lose 3/4 of) performance (and I doubt it would be any where near that bad) on keeping some of the thunks closures around so that scripting doesn't require masters degree in profiling, but we can remain in pure FP and minimize our STM usage (which also purportedly costs 4X), then if we hit 8+ cores then perfomance has improved, not to mention all the other benefits. Okay I realize that napkin calculation can't possibly encompass the details, but just make a conceptual point.