on sun NUMBER sep NUMBER bill stoddard wrote red hat linux advanced server provides many high end features such as support for asynchronous i o now read i o no longer needs to stall your application while waiting for completion can you provide a reference i could find it myself but i m too lazy well i saw it on the compaq testdrive site then had to seriously dig on the redhat site it s in one of their whitepapers URL could it be after NUMBER years without this feature unix finally catches up to windows and has i o that doesnt totally suck for nontrivial apps no way do dev poll and freebsd s kq event driven apis count imho true async io as implemented by windows NUMBER NUMBER and beyond is pretty slick but the programming model is substantially more complex than programming to an event api like dev poll and true async does not buy much if the system call overhead is low as it is with linux i havent used the fbsd poll as it s not portable select and poll still not NUMBER are all that exist in the unix world redhat of course doesnt count as portable either but it s nice they are trying the windows i o model does definately blow the doors off the unix one but then they had select to point at in it s suckiness and anything would have been an improvement unix is just now looking at it s i o model and adapting to a multiprocess multithreaded world so it s gonna be years yet before a posix api comes out of it bottom line is the do stuff when something happens model turned out to be right and the unix look for something to do and keep looking till you find it no matter how many times you have to look is not really working so great anymore adam l duncan beberg URL beberg URL 