just curious

[Peter da Silva]

I think implementing support for multiple requests is much easier than
exporting it under a normal API.
Well, for "a normal API" read "a traditional UNIX API". I don't see any 
reason the Dragonfly API couldn't be used directly by applications.

However, there 
isn't really any support on clients for say stat file x - if it has 
changed read bytes i - j and then write z to byte k.
Ah, this is the same problem, basically, as out-of-order scheduling at 
the processor "microcode" level. If there's a dependency in the 
scheduling you get a bubble in the pipeline: in this case the read and 
write are dependant on the stat, so they can execute in parallel but 
they can't start until the stat completes... *or* you can schedule the 
read anyway and throw the data away if the stat fails... and the optimum 
strategy is different depending on the relative cost of the operations 
and how close to the critical path they are.