Are there concurrent designs where the actor model isn't good for?

Question

I've noticed that all designs I have come across can be multi-threaded using the actor mode - separating each work module into a different actor and using a message queue (for me a .NET ConcurrentQueue) to pass messages. What other good multi threaded models exist?

Answer 1

To add to my last, there are various other multi threading models beyond CSP. This Wikipedia page lists several others like CCS, ACP, and LOTOS. Reading those articles hints at a deep and dark cavern where academics roam, waiting to pounce on a stray software developer.

The problem is that academic obscurity often means a complete lack of tools and libraries at the practical, usable level. It takes a lot of effort to convert a sound, proven academic study into a set of libraries and tools. There's little real incentive for the wider software community to take up a theoretical paper and turn it into a practical reality.

I like CSP because it's actually dead simple to implement your own CSP library based on select() or pselect(). I've done that several times now (I must learn about code re-use), plus the nice people at Kent University put together JCSP for those who like Java. I don't recommend developing in Occam (though it's still just about possible); support and maintainability are going to be issues going forward. CSP is probably the easiest one to get into, and given its good characteristics it's well worthwhile.