> Note that I said 'high-performance'.
> 
> Point #1: select() and anything based on it (I believe Equeue still is 
> though I haven't looked at it for quite a while) is woefully inadequate 
> for high performance I/O except in very specific circumstances.
> 
I was planning on a select() based system. Which architecture would you
recommend? I like the idea of the ring buffer. Especially for switch
type applications which are going in one port and out the other. For a
standard system that could involve 2-3 different copies when 1 would be
adequate. 

> Point #2: It is not customary for UI applications to require  
> particularly high-performance I/O, thus rendering the non-composability 
> issue moot.
> 
> I'm _not_ recommending libevent for general use, just if you want high 
> performance with an easily switchable backend implementation.

I haven't fully looked at the libevent system, but any such framework
would seem like overkill to me, when really I just need a lightweight
"deferred" class which maintains a simple callback list. In fact.. I
could leave that out of this library entirely as it may be out of the
scope of my simple project. 

The medusa/asyncore project is 847 lines of c++ code including a test
case and demo. I was hoping to stay around that number. 

Thanks, everyone for your input so far, I am rather new to ocaml and all
the resources that have been pointed out to me have been enlightening on
more subjects than this.