Thursday, August 31, 2006

Erlang concurrency discussion

Joe Armstrong has a good and interesting discussion of concurrency in Erlang. One point being, if the multiple/concurrent processes don't share memory but instead only send messages to each other, concurrency is easy and robust. Certainly, it's race conditions and incorrect locking of shared resources that makes concurrency difficult in languages which share memory.

Recently too, Joel had a discussion of MapReduce which, apparently, is something google uses to parallelize massively. Which is related to the Armstrong's article since the concurrent processes don't share memory either, they just work independently allowing massive concurrency scaling pretty much linearly as the resources.

I saw a blog post that said that Google doesn't work that way (and that discussed how map/reduce actually works in terms of the, I think, C++ API). I've lost that link though. I don't know if I ever bookmarked it, and if I did, well, I work on around 5 computers. So it's somewhere, but I don't know where it is. I could use Google Browser sync I guess. But I'm not convinced. I'm a bit paranoid about it (mainly about keeping passwords in there). I'm told that that's optional (a feature I'd expect from such an excellent company as google, certainly. But I'm still thinking about it. Oh, I'm sure I'll capitulate, eventually. But there's going to be at least one tulog before I do so.

Alright. and that's quite enough randomness already.

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