Hi Don, Its been a while (Easter holiday/motorbikes/surfing). Lots of messages to chew through after a good break. There seems to be a lot of technical detail; platform specifics and implementation. All good but its really easy (for me) to lose sight of the ball. Some definitions; * asynchronous = absence of "blocking" calls in application code * I/O = exchange of data blocks between a process and and some part of the operating system * block stream = a sequence of data blocks; complete and orderly * manager = something that can be "opened" to initiate I/O and therefore processing of a block stream * controller = some entity within a process that is interested in a block stream and will therefore negotiate with a manager * 2-way block stream = simultaneous read and write (i.e. network connection) * codec = asynchronous coding and decoding of application data to and from a block stream (AKA marshalling, serialization) For me at least the major goals are prevention of blocking (asynchronous) and re-use of codec technology across all variants of block streams. Useful paths of discussion (IMO ;-)? * possible managers - winsock, filesystem * definition of interactions (between controllers and managers) open (controller -> manager) connected (controller <- manager) read (controller <- manager) read (controller <- manager) .. end (controller <- manager) * mechanisms for exchanging messages (i.e. as above) * should IPC mechanism (as above) be re-usable in other areas, i.e. not specific to asynchronicity? even pluggable? To help keep things murky.... I have implemented something with the above goals in mind. While thinking "pure async" I got fairly close but as others have pointed out the model for interaction WRT sockets manager does not overlay well onto the filesystem manager. Said another way - applying an async approach to what is normally sync processing of a file looks lame and unwieldy. But thats probably got more to do with the (dreaded) paradigm shift and is therefore not necessarily "wrong". Lastly, I have (re-)used the codec technology in sync operations, e.g.having received an async message across a network connection, in my responding state machine I sometimes record a new state image in a file with a single blocking call. What's with that!? Well either I was just being lazy or its perfectly valid to make such judgement calls. While expending great effort to remove blocking calls it doesnt mean that they are verboten. Confused? :-) Cheers, Scott ps: did mean to send to your new subject